,,transcriber',s ,,note3 ,italic text is denoted by underscores and bold text by equal signs4 ,,the ,,philosophy ,,of ,,health2 ,,or1 ,,an ,,exposition ,,of ,,the ,,physical ,,and ,,mental ,,constitution ,,of ,,man1 ,,with ,a ,,view ,,to ,,the ,,promotion ,,of ,,human ,,longevity ,,and ,,happiness4 ,,by ,,southwood ,,smith1 ,m4,d41 ,physician to the ,london ,fever ,hospital1 to the ,eastern ,dispensary1 and to the ,jews' ,hospital4 ,,in ,,two ,,volumes4 ,,vol4 ,i4 ,,third ,,edition4 ,,london3 ,c4 ,,cox1 #ab1 ,,king ,,william ,,street1 ,,strand4 #ahdg4 ,london3 ,printed by ,w4 ,,clowes and ,,sons1 ,stamford ,street4 ,,contents ,,of ,,vol4 ,i4 ,,introduction ,page #a ,,chapter ,i4 ,characters by which living beings are distinguished from inorganic bodies--,characters by which animals are distinguished from plants--,actions common to plants and animals--,actions peculiar to animals--,actions included in the ,,organic circle--,actions included in the ,,animal circle--,organs and functions defined--,action of physical agents on organized structures--,processes of supply1 and processes of waste--,reasons why the structure of the animal is more complex than that of the plant #ac ,,chapter ,,ii4 ,two distinct lives combined in the animal--,characters of the apparatus of the organic life--,characters of the apparatus of the animal life--,characteristic differences in the action of each--,progress of life--,progress of death #ea ,,chapter ,,iii4 ,ultimate object of organization and life--,sources of pleasure--,special provision by which the organic organs influence consciousness and afford pleasure--,point at which the organic organs cease to affect consciousness and why--,the animal appetites3 the senses3 the intellectual faculties3 the selfish and sympathetic affections3 the moral faculty--,pleasure the direct1 the ordinary1 and the gratuitous result of the action of the organs--,pleasure conducive to the development of the organs1 and to the continuance of their action--,progress of human knowledge--,progress of human happiness #gc ,,chapter ,,iv4 ,relation between the physical condition and happiness1 and between happiness and longevity--,longevity a good1 and why--,epochs of life--,the age of maturity the only one that admits of extension--,proof of this from physiology--,proof from statistics--,explanation of terms--,life a fluctuating quantity--,amount of it possessed in ancient ,rome3 in modern ,europe3 at present in ,england among the mass of the people and among the higher classes #ajf ,,chapter ,v4 ,ultimate elements of which the body is composed-- ,proximate principles--,fluids and solids--,primary tissues-- ,combinations--,results--,organs1 systems1 apparatus-- ,form of the body--,division into head1 trunk1 and extremities--,structure and function of each--,regions-- ,seats of the more important internal organs #adh ,,chapter ,,vi4 ,of the blood--,physical characters of the blood3 colour1 fluidity1 specific gravity1 temperature2 quantity--,process of coagulation--,constituents of the blood2 proportions --,constituents of the body contained in the blood--,vital properties of the blood--,practical applications #ccd ,,chapter ,,vii4 ,of the circulation--,vessels connected with the heart2 chambers of the heart--,position of the heart--,pulmonic circle2 systemic circle--,structure of the heart1 artery1 and vein--,consequences of the discovery of the circulation to the discoverer--,action of the heart2 sounds occasioned by its different movements--,contraction2 dilatation--,disposition and action of the valves--,powers that move the blood--,force of the heart--,action of the arterial tubes2 the pulse2 action of the capillaries2 action of the veins--,self-moving power of the blood--,vital endowment of the capillaries2 functions--,practical applications #ceg ,,footnotes4 #djh ,,introduction4 ,the object of the present work is to give a brief and plain account of the structure and functions of the body1 chiefly with reference to health and disease4 ,this is intended to be introductory to an account of the constitution of the mind1 chiefly with reference to the development and direction of its powers4 ,there is a natural connexion between these subjects1 and an advantage in studying them in their natural order4 ,structure must be known before function can be understood3 hence the science of physiology is based on that of anatomy4 ,the mind is dependent on the body3 hence an acquaintance with the physiology of the body should precede the study of the physiology of the mind4 ,the constitution of the mind must be understood before its powers and affections can be properly developed and directed3 hence a knowledge of the physiology of the mind is essential to a sound view of education and morals4 ,in the execution of the first part of this work1 that which relates to the organization of the body1 a formidable difficulty presents itself at the outset4 ,the explanation of structure is easy when the part described can be seen4 ,the teacher of anatomy finds no difficulty in communicating to the student a clear and exact knowledge of the structure of an organ2 because1 by the aid of dissection1 he resolves the various complex substances1 of which it is built up1 into their constituent parts1 and demonstrates the relation of these elementary parts to each other4 ,but the case is different with him who attempts to convey a knowledge of the structure of an organ merely by the description of it4 ,the best conceived and executed drawing is a most inadequate substitute for the object itself4 ,it is impossible wholly to remove this difficulty3 what can be done1 by the aid of plates1 to lessen it1 is here attempted4 ,a time may come when the objects themselves will be more generally accessible3 meanwhile1 the description now given of the chief organs of the body may facilitate the study of their structure to those who have an opportunity of examining the organs themselves1 and will1 it is hoped1 enable every reader at once to understand much of their action4 ,physical science has become the subject of popular attention1 and men of the highest endowments1 who have devoted their lives to the cultivation of this department of knowledge1 conceive that they can make no better use of the treasures they have accumulated1 than that of diffusing them4 ,of this part of the great field of knowledge1 to make the rough places plain1 and the crooked places straight1 is deemed a labour second in importance only to that of extending the boundaries of the field itself4 ,but no attempt has hitherto been made to exhibit a clear and comprehensive view of the phenomena of life2 the organization upon which those phenomena depend2 the physical agents essential to their production1 and the laws1 as far as they have yet been discovered1 according to which those agents act4 ,the consequence is1 that people in general1 not excepting the educated class1 are wholly ignorant of the structure and action of the organs of their own bodies1 the circumstances which are conducive to their own health1 the agents which ordinarily produce disease1 and the means by which the operation of such agents may be avoided or counteracted2 and they can hardly be said to possess more information relative to the connexion between the organization of the body and the qualities of the mind1 the physical condition and the mental state2 the laws which regulate the production1 combination1 and succession of the trains of pleasurable and painful thought1 and the rules deducible from those laws1 having for their object such a determination of voluntary human conduct1 as may secure the pleasurable and avoid the painful4 ,yet nothing would seem a fitter study for man than the nature of man in this sense of the term4 ,a knowledge of the structure and functions of the body is admitted to be indispensable to whoever undertakes1 as the business of his profession1 to protect those organs from injury1 and to restore their action to a sound state when it has become disordered2 but surely some knowledge of this kind may be useful to those who have no intention to practise physic1 or to perform operations in surgery2 may be useful to every human being1 to enable him to take a rational care of his health1 to make him observant of his own altered sensations1 as indications of approaching sickness2 to give him the power of communicating intelligibly with his medical adviser respecting the seat and the succession of those signs of disordered function1 and to dispose and qualify him to co-operate with his physician in the use of the means employed to avert impending danger1 or to remove actual disease4 ,but if to every human being occasions must continually occur1 when knowledge of this kind would be useful1 the possession of it seems peculiarly necessary to those who have the exclusive care of infancy1 almost the entire care of childhood1 a great part of the care of the sick1 and whose ignorance1 not the less mischievous because its activity is induced by affection1 constantly endangers1 and often defeats1 the best concerted measures of the physician4 ,the bodily organization and the mental powers of the child depend mainly on the management of the infant2 and the intellectual and moral aptitudes and qualities of the man have their origin in the predominant states of sensation1 at a period far earlier in the history of the human being than is commonly imagined4 ,the period of infancy is divided by physiologists into two epochs2 the first1 commencing from birth1 extends to the seventh month3 the second1 commencing from the seventh month1 extends to the end of the second year1 at which time the period of infancy ceases1 and that of childhood begins4 ,the first epoch of infancy is remarkable for the rapidity of the development of the organs of the body3 the processes of growth are in extreme activity2 the formative predominates over the sentient life1 the chief object of the action of the former being to prepare the apparatus of the latter4 ,the second epoch of infancy is remarkable for the development of the perceptive powers4 ,the physical organization of the brain1 which still advances with rapidity1 is now capable of a greater energy1 and a wider range of function4 ,sensation becomes more exact and varied2 the intellectual faculties are in almost constant operation2 speech commences1 the sign1 and1 to a certain extent1 the cause of the growing strength of the mental powers2 the capacity of voluntary locomotion is acquired1 while passion1 emotion1 affection1 come into play with such constancy and energy1 as to exert over the whole economy of the now irritable and plastic creature a prodigious influence for good or evil4 ,if it be1 indeed1 possible to make correct moral perception1 feeling1 and conduct1 a part of human nature1 as much a part of it as any sensation or propensity--if this be possible for every individual of the human race1 without exception1 to an extent which would render all more eminently and consistently virtuous than any are at present 7and of the possibility of this1 the conviction is the strongest in the acutest minds which have studied this subject the most profoundly71 preparation for the accomplishment of this object must be commenced at this epoch4 ,but if preparation for this object be really commenced1 it implies1 on the part of those who engage in the undertaking1 some degree of knowledge2 knowledge of the physical and mental constitution of the individual to be influenced2 knowledge of the mode1 in which circumstances must be so modified in adaptation to the nature of the individual being1 as to produce upon it1 with uniformity and certainty1 a given result4 ,the theory of human society1 according to its present institutions1 supposes that this knowledge is possessed by the mother2 and it supposes1 further1 that this adaptation will actually take place in the domestic circle through her agency4 ,hence the presumed advantage of having the eye of the mother always upon the child2 hence the apprehension of evil so general1 ,i had almost said instinctive1 whenever it is proposed to take the infant1 for the purpose of systematic physical and mental discipline1 from beyond the sphere of maternal influence4 ,but society1 which thus presumes that the mother will possess the power and the disposition to do this1 what expedients has it devised to endow her with the former1 and to secure the formation of the latter8 ,i appeal to every woman whose eye may rest on these pages4 ,i ask of you1 what has ever been done for you to enable you to understand the physical and mental constitution of that human nature1 the care of which is imposed upon you8 ,in what part of the course of your education was instruction of this kind introduced8 ,over how large a portion of your education did it extend8 ,who were your teachers8 ,what have you profited by their lessons8 ,what progress have you made in the acquisition of the requisite information8 ,were you at this moment to undertake the guidance of a new-born infant to health1 knowledge1 goodness1 and happiness1 how would you set about the task8 ,how would you regulate the influence of external agents upon its delicate1 tender1 and highly-irritable organs1 in such a manner as to obtain from them healthful stimulation1 and avoid destructive excitement8 ,what natural and moral objects would you select as the best adapted to exercise and develope its opening faculties8 ,what feelings would you check1 and what cherish8 ,how would you excite aims2 how would you apply motives8 ,how would you avail yourself of pleasure as a final end1 or as the means to some further end8 ,and how would you deal with the no less formidable instrument of pain8 ,what is your own physical1 intellectual1 and moral state1 as specially fitting you for this office8 ,what is the measure of your own self-control1 without a large portion of which no human being ever yet exerted over the infant mind any considerable influence for good8 ,there is no philosopher1 however profound his knowledge1 no instructor1 however varied and extended his experience1 who would not enter upon this task with an apprehension proportioned to his knowledge and experience2 but knowledge which men acquire only after years of study1 habits which are generated in men only as the result of long-continued discipline1 are expected to come to you spontaneously1 to be born with you1 to require on your part no culture1 and to need no sustaining influence4 ,but1 indeed1 it is a most inadequate expression of the fact1 to say that the communication of the knowledge1 and the formation of the habits which are necessary to the due performance of the duties of women1 constitute no essential part of their education3 the direct tendency of a great part of their education is to produce and foster opinions1 feelings1 and tastes1 which positively disqualify them for the performance of their duties4 ,all would be well if the marriage ceremony1 which transforms the girl into the wife1 conferred upon the wife the qualities which should be possessed by the mother4 ,but it is rare to find a person capable of the least difficult part of education1 namely1 that of communicating instruction1 even after diligent study1 with a direct view to teaching2 yet an ordinary girl1 brought up in the ordinary mode1 in the ordinary domestic circle1 is intrusted with the direction and control of the first impressions that are made upon the human being1 and the momentous1 physical1 intellectual1 and moral results that arise out of those impressions6 ,i am sensible of the total inadequacy of any remedy for this evil1 short of a modification of our domestic institutions4 ,mere information1 however complete the communication of it1 can do little beyond affording a clearer conception of the end in view1 and of the means fitted to secure it4 ,even this little1 however1 would be something gained2 and the hope of contributing1 in some degree1 to the furtherance of this object1 has supplied one of the main motives for undertaking the present work4 ,meantime1 women are the earliest teachers2 they must be nurses2 they can be neither1 without the risk of doing incalculable mischief1 unless they have some understanding of the subjects about to be treated of4 ,on these grounds ,i rest their obligation to study them2 and ,i look upon that notion of delicacy1 which would exclude them from knowledge calculated1 in an extraordinary degree1 to open1 exalt1 and purify their minds1 and to fit them for the performance of their duties1 as alike degrading to those to whom it affects to show respect1 and debasing to the mind that entertains it4 ,though each part of this work will be made as complete in itself as the author is capable of rendering it1 and to that extent independent of any other part1 yet there will be found to be a strict connexion between the several portions of the whole2 and greatly as the topics included in the latter differ from those which form the earlier subjects1 the advantage of having studied the former before the latter are entered on1 will be felt precisely as the word study can be justly applied to the operation of the mind on such matters4 ,in the expository portion of the work ,i have not been anxious to abstain from the employment of technical terms1 when a decidedly useful purpose was to be obtained by the introduction of them2 but ,i have been very careful to use no such term without assigning the exact meaning of it4 ,a technical term unexplained is a dark spot on the field of knowledge2 explained1 it is a clear and steady light4 ,in order really to understand the states of health and disease1 an acquaintance with the nature of organization1 and of the vital processes of which it is the seat and the instrument1 is indispensable3 it is for this reason that the exposition of structure and function1 attempted in this first part of the work1 is somewhat full2 but there cannot be a question that1 if it accomplish its object1 it will not only enable the account of health and disease in the subsequent part of it to be much more brief1 but that it will1 at the same time1 render that account more intelligible1 exact1 and practical4 ,s4 ,s4 ,,the ,,philosophy ,,of ,,health4 ,,chapter ,i4 ,characters by which living beings are distinguished from inorganic bodies--,characters by which animals are distinguished from plants--,actions common to plants and animals--,actions peculiar to animals--,actions included in the organic circle--,actions included in the animal circle--,organs and functions defined--,action of physical agents on organized structures--,processes of supply1 and processes of waste--,reasons why the structure of the animal is more complex than that of the plant4 ,the distinction between a living being and an inorganic body1 between a plant and a stone1 is1 that the plant carries on a number of processes which are not performed by the stone4 ,the plant absorbs food1 converts its food into its own proper substance1 arranges this substance into bark1 wood1 vessels1 leaves1 and other organized structures2 grows1 arrives at maturity1 and decays2 generates and maintains a certain degree of heat2 derives from a parent the primary structure and the first impulse upon which these varied actions depend2 gives origin to a new being similar to itself1 and1 after a certain time1 terminates its existence in death4 ,no such phenomena are exhibited by the stone2 it neither absorbs food1 nor arranges the matter of which it is composed into organized structure2 nor grows1 nor decays1 nor generates heat1 nor derives its existence from a parent1 nor gives origin to a new being1 nor dies4 ,nothing analogous to the processes by which these results are produced1 is observable in any body that is destitute of life2 all of them are carried on by every living creature4 ,these processes are1 therefore1 denominated vital1 and1 being peculiar to the state of life1 they afford characters by which the living being is distinguished from the inorganic body4 ,in like manner the distinction between an animal and a plant is1 that the animal possesses properties of which the plant is destitute4 ,it is endowed with two new and superior powers1 to which there is nothing analogous in the plant2 namely1 the power of sensation1 and the power of voluntary motion2 the capacity of feeling1 and the capacity of moving from place to place as its feeling prompts4 ,the animal1 like the plant1 receives food1 transforms its food into its own proper substance1 builds this substance up into structure1 generates1 and maintains a certain temperature1 derives its existence from a parent1 produces an offspring like itself1 and terminates its existence in death4 ,up to this point the vital phenomena exhibited by both orders of living creatures are alike3 but at this point the vital processes of the plant terminate1 while those of the animal are extended and exalted by the exercise of the distinct and superior endowments of sensation and voluntary motion4 ,to feel1 and to move spontaneously1 in accordance with that feeling1 are properties possessed by the animal1 but not by the plant2 and therefore these properties afford characters by which the animal is distinguished from the plant4 ,the two great classes of living beings perform1 then1 two distinct sets of actions3 the first set is common to all living creatures2 the second is peculiar to one class3 the first set is indispensable to life2 the second is necessary only to one kind of life1 namely1 the animal4 ,the actions included in the first set1 being common to all living or organized creatures1 are called ,,organic2 the actions included in the second class1 belonging only to one part of living or organized creatures1 namely1 animals1 are called ,,animal4 ,the ,,organic actions consist of the processes by which the existence of the living being is maintained1 and the perpetuation of its species secured3 the ,,animal actions consist of the processes by which the living being is rendered percipient1 and capable of spontaneous motion4 ,the ,,organic processes comprehend those of nutrition1 respiration1 circulation1 secretion1 excretion1 and reproduction2 the first five relate to the maintenance of the life of the individual being2 the last to the perpetuation of its species4 ,the ,,animal processes comprehend those of sensation and of voluntary motion1 often denominated processes of relation1 because they put the individual being in communication with the external world4 ,there is no vital action performed by any living creature which may not be included in one or other of these processes1 or in some modification of some one of them4 ,there is no action performed by any inorganic body which possesses even a remote analogy to either of these vital processes4 ,the line of demarcation between the organic and the inorganic world is1 therefore1 clear and broad2 and the line of demarcation between the two great divisions of the organic world1 between the inanimate and the animate1 that is1 between plants and animals1 is no less decided3 for1 of the two sets of actions which have been enumerated1 the one1 as has just been stated1 is common to the whole class of living beings1 while the second set is peculiar to one division of that class4 ,the plant performs only the organic actions3 all the vital phenomena it exhibits are included in this single circle2 it is1 therefore1 said to possess only organic life3 but the animal performs both organic and animal actions1 and is therefore said to possess both organic and animal life4 ,both the organic and the animal actions are accomplished by means of certain instruments1 that is1 organized bodies which possess a definite structure1 and which are moulded into a peculiar form4 ,such an instrument is called an organ1 and the action of an organ is called its function4 ,the leaf of the plant is an organ1 and the conversion of sap by the leaf into the proper juice of the plant1 by the process called respiration1 is the function of this organ4 ,the liver of the animal is an organ2 and the conversion of the blood that circulates through it into bile1 by the process of secretion1 is its function4 ,the brain is an organ2 the sentient nerve in communication with it is also an organ4 ,the extremity of the sentient nerve receives an impression from an external object1 and conveys it to the brain1 where it becomes a sensation4 ,the transmission of the impression is the function of the nerve2 the conversion of the impression into a sensation is the function of the brain4 ,the living body consists of a congeries of these instruments or organs3 the constituent matter of these organs is always partly in a fluid and partly in a solid state4 ,of the fluids and solids which thus invariably enter in combination into the composition of the organs1 the fluids may be regarded as the primary and essential elements1 for they are the source and the support of the solids4 ,there is no solid which is not formed out of a fluid2 no solid which does not always contain1 as a constituent part of it1 some fluid1 and none which is capable of maintaining its integrity without a continual supply of fluids4 ,whatever be the intimate composition of the fluids out of which the solids are formed1 the investigation of which is more difficult than that of the solids and the nature of which is therefore less clearly ascertained1 it is certain that all the matter which enters into the composition of the solid is disposed in a definite order4 ,it is this disposition of the constituent matter of the living solid in a definite order that constitutes the arrangement so characteristic of all living substance4 ,definite arrangements are combined in definite modes1 and the result is what is termed organization4 ,from varied arrangements result different kinds of organized substances1 each endowed with different properties1 and exhibiting peculiar characters4 ,by the recombination of these several kinds of organized substances1 in different proportions and different modes1 are formed the special instruments1 or organs1 of which we have just spoken2 while it is the combining1 or the building up of these different organized substances into organs1 that constitutes structure4 ,in the living body1 not only is each distinct organ alive1 but1 with exceptions so slight that they need not be noticed here1 every solid which enters into the composition of the organ is endowed with vital properties4 ,this is probably the case with the primary substances or tissues which compose the several organs of the plant2 but that the animal solids are alive is indubitable2 nay1 the evidence is complete1 that many even of the animal fluids possess vitality4 ,the blood in the animal is as truly alive as the brain1 and the bone as the flesh4 ,the organized body1 considered as a whole1 is the seat of life2 but life also resides in almost every component part of it4 ,yet the matter out of which these living substances is formed is not alive4 ,by processes of which we know nothing1 or1 at least1 of which we see only the first steps1--matter1 wholly destitute of life1 is converted into living substance4 ,the inorganic matter1 which is the subject of this wonderful transformation1 is resolvable into a very few elementary substances4 ,in the plant1 these substances consist of three only1 namely1 oxygen1 hydrogen1 and carbon4 ,the first two are ariform or gaseous bodies2 the last is a solid substance1 and it is of this that the plant is chiefly composed3 hence the basis of the plant is a solid4 ,the elementary bodies1 into which all animal substance is resolvable1 are four1 namely1 azote1 oxygen1 hydrogen1 and carbon4 ,into every animal fluid and solid this new substance azote enters so largely1 that it may be considered as the fundamental and distinctive element of the animal organization3 hence the basis of the animal is an ariform or gaseous fluid4 ,the animal is composed of air1 the plant of solid matter2 and this difference in their elementary nature gives origin to several distinctive characters between the plant and the animal1 in addition to those which have been already stated4 ,thus the characters of the plant are solidity1 hardness1 fixedness1 and durability2 while the animal is comparatively fluid1 soft1 volatile1 and perishable2 and the reason is now manifest4 ,the basis of the animal being an ariform fluid1 its consistence is softer than that of the plant1 the basis of which is a firm solid2 and1 at the same time1 the component elements of the animal being more numerous than those of the plant1 and the fluidity of these elements1 and of the compounds they form1 greatly favouring their action and reaction on each other and on external agents1 the animal body is more volatile and perishable during life1 and more readily decomposed after death4 ,it has been stated1 that the object of every structure or organ of the living body1 is the performance of some special action or function1--the ultimate object of the fluids being the production of the solids2 the ultimate object of the solids being the formation of organs2 the ultimate object of organs being the performance of actions or functions2 while it is in the performance of actions or functions that life consists4 ,functions carried on by organs2 organs in action2 special organs performing definite actions1 this it is that constitutes the state of life4 ,every particle of matter which enters into the composition of the living body has thus its own place1 forming1 or destined to form1 a constituent part of some organ2 every organ has its own action2 all the organs of the body form the body2 and all the actions of all the organs constitute the aggregate of the vital phenomena4 ,every organ is excited to action1 or its function is called into operation by means of some external body4 ,the external bodies capable of exciting and maintaining the functions of living organs1 consist of a definite class4 ,because these bodies belong to that department of science which is called physical1 they are termed physical agents4 ,they are air1 water1 heat1 cold1 electricity1 and light4 ,without the living organ1 the physical agent can excite no vital action3 without the physical agent1 the living organ can carry on no vital process4 ,the plant cannot perform the vital process of respiration without the leaf1 nor1 with the leaf1 without air4 ,the physical agent acts upon the living organ2 the living organ reacts upon the physical agent1 and the action between both is definite4 ,in the lung of the animal a certain principle of the air unites1 in definite proportions1 with a certain principle of the blood2 the oxygen of the air combines with the carbon of the blood2 the air is changed by the abstraction of its oxygen2 the blood is changed by the abstraction of its carbon4 ,atmospheric air goes to the lung1 but atmospheric air does not return from the lung2 it is converted into a new substance by the action of the organ3 it is changed into carbonic acid by the union of a given quantity of oxygen1 which it transmits to the organ1 with a given quantity of carbon which the organ conveys to it4 ,venous blood goes to the lung1 but venous blood does not return from the lung2 it is converted1 by the instrumentality of the organ1 into a new substance1 into arterial blood1 by giving to the air carbon1 and by receiving from the air oxygen4 ,in this manner the change in the physical agent is definite and uniform2 and the change in the living substance is equally definite and uniform4 ,it is this determinate interchange of action between the living organ and the physical agent that constitutes what is termed a vital process4 ,all vital processes are carried on by living organs2 the materials employed in all vital processes are physical agents2 the processes themselves are vital functions4 ,all the changes produced by all the organs of the plant upon physical agents1 and all the changes produced by all physical agents upon the organs of the plant1 constitute all the vital processes of the plant--comprehend the whole sum of its vital phenomena4 ,the root1 the trunk1 the woody substance1 the bark1 the ascending vessels bearing sap1 the descending vessels bearing secreted fluids1 the leaves1 the flowers1 these are the living organs of the plant4 ,air1 water1 heat1 cold1 electricity1 light1 these are the physical agents which produce in these organs definite changes1 and which are themselves changed by them in definite modes2 and the whole of these changes1 taken together1 comprehend the circle of actions1 or the range of functions performed by this living being4 ,in the state of life1 during the interchange of action which thus incessantly goes on between physical agents and vital organs1 the laws to which inorganic matter is subject are resisted1 controlled1 and modified4 ,physical and chemical attractions are brought under the influence of a new and superior agency1 with the laws of which we are imperfectly acquainted1 but the operation of which we see1 and which we call the agency of life4 ,air1 water1 heat1 electricity1 are physical agents1 which subvert the most intimate combinations of inorganic bodies1 resolving them into their simple elements1 and recombining these elements in various modes1 and thus forming new bodies1 endowed with totally different properties2 but the physical and chemical agencies by which these changes are wrought in the inorganic1 are resisted1 controlled1 and modified by the living body3 resisted1 for these physical agents do not decompose the living body2 controlled and modified1 for the living body converts these very agents into the material for sustaining its own existence ,of all the phenomena included in that circle of actions which we designate by the general term life1 this power of resisting the effects universally produced by physical agents on inorganic matter1 and of bringing these very agents under subjection to a new order of laws1 is one of the most essential and distinctive4 ,all vital processes are processes of supply1 or processes of waste4 ,by every vital action performed by the organized body1 some portion of its constituent matter is expended4 ,numerous vital actions are constantly carried on for the sole purpose of compensating this expenditure4 ,every moment old particles are carried out of the system2 every moment new particles are introduced into it4 ,the matter of which the organized1 and more especially the animal1 body is composed1 is thus in a state of perpetual flux2 and in a certain space of time it is completely changed1 so that of all the matter that constitutes the animal body at a given point of time1 not a single particle remains at another point of time at a given distance4 ,all the wants of the economy of the plant are satisfied by a due supply of air1 water1 heat1 cold1 electricity1 and light4 ,some of these physical agents constitute the crude aliment of the plant2 others produce in this aliment a series of changes1 by which it is converted from crude aliment into proper nutriment1 while others act as stimulants1 by which movements are excited1 the ultimate object of which is the distribution of the nutriment to the various parts of the economy of the plant4 ,the same physical agents are indispensable to the support of the animal body2 but the animal cannot be sustained by these physical agents alone2 for the maintenance of animal life1 in some shape or other1 vegetable or animal matter1 or both in a certain state of combination1 must be superadded3 hence another distinction between the plant and the animal1--the necessity1 on the part of the animal1 of an elaborated aliment to maintain its existence4 ,by the vital processes of its economy1 the plant converts inorganic into organic matter2 by the vital processes of its economy1 the animal converts matter1 already rendered organic1 into its own proper substance4 ,the plant is thus purveyor to the animal3 but it is more than purveyor to it2 for while it provides1 it also prepares its food2 it saves the animal one process1 that of the transmutation of inorganic into organic matter4 ,the ultimate end1 or the final cause of the vital processes performed by the first class of living beings1 is thus the elaboration of aliment for the second3 the inferior life is spent in ministering1 and the great object of its being is to minister to the existence of the superior4 ,at the point at which organization commences structure is so simple that there is no manifest distinction of organs4 ,several functions are performed apparently by one single organized substance4 ,the lowest plants and the lowest animals are equally without any separate organs1 as far as it is in our power to distinguish them1 for carrying on the vital actions they perform4 ,an organized tissue1 apparently of an homogeneous nature1 containing fluid matter1 is all that can be made out by which the most simply-constructed plant carries on its single set1 and by which the most simply-constructed animal carries on its double set1 of actions4 ,but this simplicity of structure exists only at the very commencement of the organized world4 ,every advancement in the scale of organization is indicated by the construction of organs manifestly separate for the performance of individual functions2 and1 invariably1 the higher the being1 the more complete is this separation of function from function1 and1 consequently1 the greater the multiplication of organs1 and the more elaborate and complex the structure2--and hence another distinction between the plant and the animal4 ,the simplicity of the structure of the plant is in striking contrast to the complexity of the structure of the animal2 and this difference is not arbitrary2 it is a matter of absolute necessity1 and the reason of this necessity it will be instructive to contemplate4 ,the plant1 as has been shown1 performs only one set of functions1 the organic2 while the animal performs two sets of functions1 the organic and the animal4 ,the animal1 then1 performs more functions than the plant1 and functions of a higher order2 it carries on its functions with a greater degree of energy2 its functions have a more extended range1 and all its functions bear a certain relation to each other1 maintaining an harmonious action4 ,the number1 the superiority1 the relation1 the range1 and the energy of the functions performed by the animal are1 then1 so many conditions1 which render it absolutely indispensable that it should possess a greater complexity of structure than the plant4 #a4 ,to build up structure is to create1 to arrange1 and to connect organs4 ,organs are the instruments by which functions are performed1 and without the instrument there can be no action4 ,with as many more organs than the plant possesses the animal must1 therefore1 be provided1 as are necessary to carry on the additional functions it performs4 ,organs1 for its organic functions1 it must have as well as the plant2 but to these must be superadded organs of another class1 for which the plant has no need1 namely1 organs for its animal functions4 ,two sets of organs must1 therefore1 be provided for the animal1 while the plant requires but one4 #b4 ,some functions performed by the animal are of a higher order than any performed by the plant1 and the superior function requires a higher organization4 ,the construction of an organ is complex as its action is elevated2 the instrument is elaborately prepared in proportion to the nobleness of its office4 ,illustration3 ,fig4 ,i4 ,illustration3 ,fig4 ,,ii4 ,illustration3 ,fig4 ,,iii4 ,illustration3 ,fig4 ,,iv4 #c4 ,but this is not all2 for the addition of a superior function requires not only the addition of an organ having a corresponding superiority of structure1 but it requires1 further1 that a certain elevation of structure should be communicated to all the organs of all the inferior functions1 on account of the relation which it is necessary to establish between function and function4 ,unless the organ of an inferior function be constructed with a perfection corresponding to that of the organ of a superior function1 the inferior will be incapable of working in harmony with the superior4 ,take1 for example1 the inferior function of nutrition3 nutrition is an organic function equally necessary to the plant and to the animal1 and requiring in both organs for performing it2 but this function cannot be performed in the animal by organs as simple as suffice for the plant4 ,nutrition1 in the plant1 is carried on in the following mode3--,the root of the plant is divided1 like the trunk1 into numerous branches 7fig4 ,i4 #a74 ,these branches divide and subdivide into smaller and smaller branches1 until at last they reach an extreme degree of minuteness 7fig4 ,i4 #b #b74 ,the smallest of these divisions1 called1 from their hair-like tenuity1 capillary 7fig4 ,i4 #b #b71 are provided with a peculiar structure1 which is endowed with a specific function4 ,in most plants this peculiar structure is found at the terminal point of the rootlet 7fig4 ,i4 #b #b72 but in some plants the capillary branches of the rootlets are provided with distinct bodies 7fig4 ,,ii4 #a #b71 scarcely to be discerned when the root has been removed some time from the soil1 and has become dry 7fig4 ,,ii4 #b #b72 but which1 in a few minutes after the root has been plunged in water1 provided the plant be still alive1 become turgid with fluid1 and1 consequently1 distinctly visible 7fig4 ,,ii4 #a #a #a74 ,these bodies1 when they exist1 or the terminal point of the rootlet when these bodies are absent1 are termed spongeol1 or spongeoles2 and the structure and function of the organ1 in both cases1 are conceived to be precisely the same4 ,in both the organ consists of a minute cellular structure4 ,fig4 ,,iii4 #a1 shows this structure as it appears when the object is magnified4 ,the office of this organ is to absorb the aliment of the plant from the soil2 and so great is its absorbing power1 that1 as is proved by direct experiment1 it absorbs the colouring molecules of liquids1 though these molecules will not enter the ordinary pores1 which are of much greater magnitude4 ,with the spongeoles are connected vessels which pass through the substance of the stem or trunk to the leaf4 ,fig4 ,,iii4 #b1 shows these tubes springing from the cellular structure of the spongeole1 and passing up to the stem or trunk4 ,fig4 ,,iv4 #b1 exhibits a magnified view of the appearance of the mouths of these tubes on making an horizontal section of the spongeole4 ,fig4 ,v4 #a #a #a1 exhibits a view of these tubes passing to the leaf4 ,figs4 ,,vi4 and ,,vii4 #a #a #a #a1 show these vessels spread out upon1 and ramifying through1 the leaf4 ,the crude aliment1 borne by these tubes to the leaf1 is there converted into proper nutriment2 and from the leaf1 when duly elaborated1 this proper nutriment is carried out by ducts to the various organs of the plant1 in order to supply them with the aliment they need4 ,illustration3 ,fig4 ,v4 ,now1 for carrying on the process of nutrition in this mode1 there must be organs to absorb the crude aliment1 organs to convey the crude aliment to the laboratory1 the leaf1 in which it is converted into proper nutriment2 and1 finally1 organs for carrying out this proper nutriment to the system4 ,complication of structure1 to this extent1 is indispensable2 and1 accordingly1 with spongeol1 with sap-vessels1 with leaves1 with distributive ducts1 the plant is provided4 ,without all the parts of this apparatus it could not carry on its function3 any further complication would be useless4 ,illustration3 ,fig4 ,,vi4 ,but1 suppose a new and superior function to be added to the plant2 suppose it to be endowed with the power of locomotion1 what would be the consequence of communicating to it this higher power8 ,that its former state of simplicity would no longer suffice for the inferior function4 ,why8 because the exercise of the superior would interrupt the action of the inferior function4 ,nutrition by imbibition1 and the exercise of locomotion1 cannot go on simultaneously in the same being4 ,the plant is fixed in the soil by its roots2 and from this1 its state of immobility1 results this most important consequence1 that its spongeol are always in contact with its food4 ,illustration3 ,fig4 ,,vii4 ,illustration3 ,fig4 ,,viii4 ,but we may imagine a plant not fixed to the soil2 a plant so constituted as to be capable of moving from place to place2 such a plant would not be always in contact with its food1 and therefore1 as it exercised its faculty of locomotion1 it could not but interrupt or suspend its function of nutrition4 ,in a being capable of carrying on these two functions simultaneously1 the entire apparatus of the function of nutrition must then be modified4 ,instead of having spongeol fixed immovably in the earth1 and spread out in a soil adapted to transmit to these organs nutrient matter in a state fitted for absorption1 it must be provided with a reservoir for containing its food1 in order that it may carry its aliment about with it in all its changes of place4 ,and such is the modification uniformly found in all animals3 an internal reservoir for containing its food is provided1 perhaps1 for every animal without exception4 ,even the simplest and minutest creatures with which the microscope has made us acquainted1 the lowest tribes of the ,infusoria 7fig4 ,,viii471 the sentient1 self-moving cellules1 placed at the very bottom of the animal scale1 possess this modification of structure4 ,for a long time it was conceived that these minute and simple creatures were without distinction of parts1 that they had no separate organs for the reception and digestion of their food2 that they absorbed their aliment through the porous tissue of which their body is composed2 that thus1 instead of having a separate stomach1 their entire body is a stomach1 and instead of having even as much as a separate organ for absorption1 like the more perfect plant1 the whole body might be considered as a single spongeole4 ,but1 by a simple and beautiful experiment1 a ,german physiologist has shown the incorrectness of this opinion1 and has established the fact1 that the distinction between the plant and the animal1 here contended for1 is found even at the very lowest point of the animal scale4 ,like other physiologists1 conceiving that the difficulty of discovering the structure of the lower tribes of the animalculi might be owing to the transparency or the tissues of which they are composed1 it struck ,ehrenberg1 that if he could feed them with coloured substances1 he might obtain some insight into their organization4 ,in his first endeavours to accomplish this object he failed1 for he employed the pigments in ordinary use2 but either the animals would not touch aliment thus adulterated1 or those that did so were instantly killed4 ,it then occurred to him1 that these colours are adulterated with lead and other substances1 in all probability noxious to the little subjects of his experiment4 ,what ,i require1 said he1 is some vegetable or animal colouring matter perfectly pure4 ,he then tried perfectly pure indigo and perfectly pure carmine4 ,his success was now complete3 in a minute or two1 after mixing with their food pure vegetable colouring matter1 he observed in the interior of the body of these creatures minute spots of a definite figure1 and of the colour of the pigment employed 7fig4 ,,viii4 #a #a #a #a74 ,the form and magnitude of these spots were different in different tribes1 but the same in the same individual1 and even in the same species 7fig4 ,,ix4 #a #a1 fig4 ,x4 #a #a74 ,no other parts of the body were tinged with the colour1 though the animals remained in the coloured fluid for days together4 ,this was decisive4 ,this physiologist had now obtained an instrument capable of revealing to him the interior organization of a class of beings1 the structure of which had heretofore been wholly unknown4 ,on applying it to the ,,monas ,,termo 7fig4 ,,viii471 the animated point1 or cellule1 which stands at the bottom of the animal scale1 he discovered1 in the posterior portion of its body1 several coloured spots which constitute its stomachs 7fig4 ,,viii4 #a #a #a #a74 ,the different situations and different forms of the stomach in different tribes of these creatures1 are represented by the coloured portions 7fig4 ,,viii4 #a1 fig4 ,,ix4 #a1 fig4 ,x4 #a71 in which the currents of fluid flowing to their mouths are seen 7fig4 ,,ix4 #b1 fig4 ,x4 #b74 ,these experiments go far towards establishing the fact1 that every animal1 even the very lowest1 has an external mouth and an internal stomach1 and that it takes its food by an act of volition4 ,illustration3 ,fig4 ,,ix4 ,illustration3 ,fig4 ,x4 ,but if the proof of this must be admitted to be still imperfect with regard to the lowest tribes of animals1 it is certain that1 as we ascend in the scale of organization1 the nutritive apparatus is uniformly arranged in this mode4 ,every animal of every class large enough to be distinctly visible1 and the structure of which is not rendered inappreciable by the transparency of its solids and fluids1 is manifestly provided with a distinct internal reservoir for containing its food4 ,on the internal surface of this reservoir open the mouths of vessels1 minute in size but countless in number1 which absorb the food from the stomach4 ,fig4 ,,xi4 shows these vessels opening on the inner surface of the stomach1 the white points representing their mouths1 turgid with the food they have absorbed4 ,fig4 ,,xii4 exhibits magnified views of the same vessels1 the points representing their open mouths1 and the lines the vessels themselves in continuation with their mouths4 ,fig4 ,,xiii4 shows the appearance of the inner surface of the intestine soon after the animal has taken food2 the smaller white lines 7#a #a #a #a7 representing the absorbent vessels full of digested food1 and the larger lines 7#b #b #b #b7 the trunks of the absorbent vessels formed by the union of many of the smaller4 ,illustration3 ,fig4 ,,xi4 ,illustration3 ,fig4 ,,xii4 ,from this account1 it is clear that the absorbing vessels of the stomach perform an office precisely analogous to that of the spongeoles of the root4 ,what the soil is to the plant1 the stomach is to the animal4 ,the absorbing vessels diffused through the stomach1 as long as the stomach contains food1 are in exactly the same condition as the spongeoles of the root spread out in the soil2 and the absorbing vessels of the stomach are as much and as constantly in contact with the aliment1 which it is their office to take into the system1 as the spongeoles of the root4 ,such1 then1 is the expedient adopted to render the function of nutrition compatible with the function of locomotion4 ,a reservoir of food is placed in the interior of the animal1 provided with absorbent vessels which are always in contact with the aliment4 ,in this mode1 contact with aliment is not disturbed by continual change of place2 the organic process is not interrupted by the exercise of the animal function4 ,illustration3 ,fig4 ,,xiii4 ,but the more elaborate organization which it is necessary to impart to the apparatus of the inferior function1 in consequence of the communication of a superior faculty1 is not completed simply by the addition of this new organ1 the stomach4 ,other complications are indispensable2 for if food be contained in an isolated organ1 placed in the interior of the body1 means must be provided for conveying the food into this organ2 hence the necessity of an apparatus for deglutition4 ,moreover1 the food having been conveyed to the stomach1 and having undergone there the requisite changes1 means must next be provided for conveying it from the stomach to the other parts of the body2 hence the necessity of an apparatus for the circulation4 ,but food1 however elaborately prepared by the stomach1 is incapable of nourishing the body1 until it has been submitted to the action of atmospheric air2 hence the necessity of an additional apparatus1 either for conveying food to the air1 or for transmitting air to the food1 or for bringing both the food and the air into contact in the same organ4 ,and1 when structure after structure has been built up1 in order to carry on this extended series of processes1 the number of provisions required is not even yet complete2 for of the most nutritious fond the whole mass is not nutritive2 and even the whole of that portion of it which is actually applied to the purpose of nutrition1 becomes1 after a time1 worn out1 and must be removed from the system2 hence the necessity of a further apparatus for excretion4 ,that nutrition and locomotion may go on together1 it is clear1 then1 that there must be provided a distinct apparatus for containing food1 a distinct apparatus for deglutition1 a distinct apparatus for circulation1 a distinct apparatus for respiration1 a distinct apparatus for excretion1 and so on2 and that1 in this manner1 the communication of a single function of a superior order renders a modification not merely of one but of many inferior functions absolutely indispensable1 in order to adjust the one to the other1 and to enable them to act in harmony4 ,but the necessary complication of structure does not stop even here2 for the communication of one function of a superior order imposes the necessity of communicating still another4 ,locomotion cannot be exercised without perception2 sensation is indispensable to volition1 and volition1 of course1 to voluntary motion4 ,a being endowed with the power of moving from place to place1 without possessing the power of perceiving external objects1 must be speedily destroyed4 ,the communication of sensation to a creature fixed immovably to a single spot1 conscious of the approach of bodies1 but incapable of avoiding their contact1 would be not only useless but pernicious1 since it would be to make a costly provision for the production of pain1 and nothing else2 but the communication of locomotion without sensation would be as unwisely defective1 as the former would be perniciously expensive2 since it would be to endow a being with a faculty1 the exercise of which would be fatal to it for the want of a second faculty to guide the first4 ,nor could the possession of locomotion1 without the further possession of sensation1 be otherwise than fatal1 for another reason4 ,consciousness is not necessary to nutrition as performed by the plant1 but it is indispensable to nutrition as performed by the animal3 for if the food of the animal be not always on the same spot with itself2 if it be under the necessity of searching for it1 and of conveying it1 when found1 into the interior of its body1 it must1 of course1 possess the power of perceiving it when within its reach1 and of apprehending and appropriating it by an act of volition1 of none of which actions is it capable without the possession of sensation4 ,again1 then1 we see that1 in order to secure harmonious action1 function must be put in relation with function4 ,in order to prevent jarring and mutually-destructive action1 function must be superadded to function1 and throughout the animal creation the complication of structure1 which is necessary for the accomplishment of these ends1 is given without parsimony1 but without profusion3 nothing is given which is not needed1 nothing is withheld which is required4 #d4 ,as we ascend in the scale of organization1 numerous functions being carried on1 and numerous organs constructed for performing them1 it is obvious that the range of each function must be proportionally extended2 the range necessarily increasing with the multiplication of organ and function3 and this is another cause of the unavoidable complication of structure4 ,slight consideration will suffice to show the necessary connexion between an extended range of action and complication of structure4 ,take1 as an example1 the organic function of respiration3 respiration is the function by which air is brought into contact with food2 it is the completion of digestion4 ,the sole end of all the apparatus that belongs to this function is to bring the air and the food into a certain degree of proximity4 ,now1 when all the substances that enter into the composition of the body of an animal are slight1 delicate1 and permeable to air 7as in fig4 ,,xiv471 and when the body is always surrounded by air1 air must at all times be in contact with the particular organ that contains the food1 no less than with the general system to which the food is distributed4 ,in this case1 to construct a separate apparatus for containing air would be useless1 because wherever food is1 there air must be1 since it constantly permeates every part of the body4 ,illustration3 ,fig4 ,,xiv4 ,when1 on the other hand1 the tissues are so firm and dense as to be impermeable2 when they are folded into bulky and complex organs1 and when these organs are placed in situations to which the external air cannot reach1 the construction of a separate apparatus for respiration is indispensable4 ,the respiratory apparatus consists either of organs for carrying air to the food1 or of organs for carrying food to the air4 ,the one or the other is adopted1 according to the nature of the body4 ,if the size of the animal be small2 if the tissues which form the solid portion of its body be delicate in texture2 if1 at the same time1 the wants of its economy require that its food should be highly arated 7for there is the closest connexion between energy of function and perfect aration of the food71 an apparatus of sufficient magnitude to arate the food in a high degree would occupy the entire bulk of the body4 ,in such a case1 it is easier to carry air to the food than food to the air2 it is better to make the entire body a respiratory organ1 than to construct a respiratory organ disproportioned to the magnitude of the body4 ,air-tubes diffused through every part of the body1 and opening on its external surface1 would obviously afford to every point of the system an easy access of air4 ,by an expedient of this kind the system might be highly arated1 while the respiratory apparatus would occupy but a comparatively small space2 the function might be performed on an extended scale1 while there would be no necessity for encumbering a minute body with a bulky organ4 ,and this is the mode in which respiration is carried on in large tribes of creatures1 whose body is small in size and delicate in texture1 and the functions of whose economy are performed with energy 7fig4 ,,xv474 ,illustration3 ,fig4 ,,xv4 ,the ,achilles ,butterfly of ,south ,america 7,papilio ,achilles71 showing the trache on the upper and under side of the wings4 ,but this contrivance will not do when the animal is of large magnitude2 when its body is divided into numerous compartments2 when these compartments extend far beneath the external surface2 when important organs are placed in deeply-seated cavities2 and when the substances that compose the organs are dense1 hard1 thick1 and convoluted4 ,to construct air-tubes of the requisite diameter and length1 always open1 always in a condition to permit the ingress and egress of an adequate current of air to and from the remotest nook and corner of a body such as this1 would be difficult1 if not impossible4 ,at all events1 it is easier1 in such a case1 to carry the food to the air1 than the air to the food4 ,but1 for the accomplishment of this purpose1 what is necessary8 ,an organ for containing food2 an organ for containing air2 vessels to carry food to and from the receptacle of the aliment2 vessels to carry air to and from the receptacle of the air2 expedients to expose a stream of food to a current of air2 and1 finally1 tubes to carry out to the system the product of this complicated operation4 ,accordingly1 a reservoir of food and a reservoir of air2 an apparatus by which both are conveyed to their respective receptacles2 and an apparatus by which both are brought into contact sufficiently close to admit of their mutual action1 are all combined in the lung of the animal1 and in the mechanism by which its movements are effected4 ,the object is accomplished1 but the apparatus by which it is effected is as complex in structure as it is efficient in action2 the result simple2 the means by which the result is secured1 highly complicated4 ,and if this be true of an inferior or organic function1 it is still more strikingly true of a superior or animal function4 ,the relation is still stricter between the complexity of the apparatus of sensation and the range of feeling1 than between the complexity of the apparatus of respiration and the range of the respiratory process4 ,the greater the number of the senses1 the greater the number of the organs of sense2 the more accurate and varied the impressions conveyed by each1 the more complex the structure of the instrument by which they are communicated2 the more extended the range of the intellectual operations1 the larger the bulk of the brain1 the greater the number of its distinct parts1 and the more exquisite their organization4 ,from the point of the animal scale1 at which the brain first becomes distinctly visible1 up to man1 the basis of the organ is the same2 but1 as the range of its function extends1 part after part is superadded1 and the structure of each part becomes progressively more and more complex4 ,the evidence of this1 afforded by comparative anatomy1 is irresistible1 and the interest connected with the study of it can scarcely be exceeded4 #e4 ,in the last place1 structure is complex in proportion to the energy of function4 ,the greater the power with which voluntary motion is capable of being exerted1 the higher the organization of the apparatus by which it is performed2 the more compact and dense the shell1 the cartilage1 the bone1 the firmer the fibre of the muscle1 and1 in general1 the greater its comparative bulk4 ,the wing of the eagle is as much more developed than the wing of the wren1 as its flight is higher1 and its speed swifter4 ,the muscles which give to the tiger the rapidity and strength of its spring possess a more intense organization than those which slowly move on the tardigrade sloth4 ,the structure of the brain of man is more exquisite than that of the fish1 as his perceptions are more acute1 and capable of greater combination1 comprehension1 and continuity4 ,thus we see that the organization of the animal is more complex than that of the plant1 not from an arbitrary disposition1 but from absolute necessity4 ,the few and simple functions performed by the plant require only the few and simple organs with which it is provided3 the numerous and complicated functions performed by the animal require its numerous and complicated organs3 the plant1 simple as it is in structure1 is destitute of no organ required by the nature of its economy2 the animal1 complex as it is in structure1 is in possession of no organ which it could dispense with3 from the one1 nothing is withheld which is needed2 to the other1 nothing is given which is superfluous3 in the one1 there is economy without niggardliness2 in the other1 munificence without waste4 ,,chapter ,,ii4 ,two distinct lives combined in the animal--,characters of the apparatus of the organic life--,characters of the apparatus of the animal life--,characteristic differences in the action of each--,progress of life--,progress of death4 ,of the two sets of functions carried on by living beings1 it has been shown1 that the plant performs only one1 while the animal exercises both4 ,the two lives thus in continual play in the animal differ from each other as much as the process of vegetation differs from that of thought1 yet they are united so closely1 and act so harmoniously1 that their existence as distinct states is not only not apparent to ordinary observation1 but the very discovery of the fact is of recent date1 and forms one among the splendid triumphs of modern physiology4 ,their action is perfect1 yet their separate identity is so distinctly preserved1 that each has its own apparatus and its own action1 which are not only not the same1 but1 in many interesting circumstances1 are in striking contrast to each other4 #a4 ,in general the organs that belong to the apparatus of the organic life are single1 and not symmetrical2 the organs that belong to the apparatus of the animal life are either double1 or symmetrical1 or both4 ,as will be shown hereafter1 the heart1 the lungs1 the stomach1 the intestines1 the liver1 the pancreas1 the spleen1 the instruments by which the most important functions of the organic life are carried on1 are single organs4 7,chap4 #e47 ,the figure of each is more or less irregular1 so that if a line were carried through their centre1 it would not divide them into two equal and precisely corresponding portions4 ,on the contrary1 the organs of the animal life are symmetrical4 ,the brain and the spinal cord are divisible into two perfectly equal parts4 7,chap4 #e47 ,the nerves which go off from these organs for the most part go off in pairs equal in size and similar in distribution4 7,ibid47 ,the trunk1 so important an instrument of voluntary motion1 when well formed1 is divisible into two perfectly corresponding portions4 7,ibid47 ,the muscular apparatus of one half of the body is the exact counterpart of that of the other2 while the arms1 the hands1 and the lower extremities are not only double1 but the organization of the one is precisely similar to that of its fellow4 #b4 ,in general1 the apparatus of the organic life is placed in the interior of the body1 while that of the animal life is placed on the external surface4 ,the organic organs are the instruments by which life is maintained4 ,there is no action of any one of them that can be suspended even for a short space of time without the inevitable extinction of life4 ,but the animal organs are not so much instruments of life as means by which a certain relation is established between the living being and external objects4 ,and this difference in their office is the reason of the difference in their position4 ,existence depending on the action of the organic organs1 they are placed in the interior of the body2 they are fixed firmly in their situation in order that they may not be disturbed by the movements of locomotion2 they are enveloped in membranes1 covered by muscles1 placed under the shelter of bones1 and every possible care is taken to secure them from accident and to shield them from violence4 ,existence not being immediately dependent on the action of the organs of the animal life1 they do not need to be protected from the contact of external objects with extraordinary care1 but it is necessary to the performance of their functions that they should be placed at the exterior of the body4 ,and there they are placed1 and so placed as to afford an effectual defence to the organic organs4 ,thus the groundwork of the animal is made the bulwark of the organic life4 ,the muscles1 the immediate agents by which voluntary motion is effected1 and the bones1 the fixed points and the levers by which that motion acquires the nicest precision and the most prodigious rapidity and power1 are so disposed that1 while the latter accomplish1 in the most perfect manner1 their primary and essential office in relation to the muscles1 they serve a secondary but scarcely less important office in relation to the internal viscera4 ,as we advance in our subject1 we shall see that a beautiful illustration of this is afforded in the structure and action of the trunk2 that the trunk is moveable2 that it is composed of powerful muscles1 and of firm and compact bones2 and that while its movements are effected by the action of the muscles which are attached to the bones1 these bones enclose a cavity1 in which are placed the lungs1 the heart1 the great trunks of the venous system1 the great trunks of the arterial system1 and the main trunk of the thoracic duct1 the vessel by which the digested aliment is carried into the blood4 7,chap4 #e47 ,thus1 by these strong and firm bones1 together with the thick and powerful muscles that rest upon them1 is formed a secure shelter for a main portion of the apparatus of the organic functions of respiration1 circulation1 and digestion4 ,the bones and muscles of the thorax1 themselves performing an important part in the function of respiration1 afford to the lungs the chief organ of this function1 composed of tender and delicate tissues1 easily injured1 and the slightest injury perilling life1 a free and secure place to act in4 ,the fragile part of the apparatus is defended by the osseous portion of it1 the play of the latter being equally essential to the function as that of the former4 ,in like manner the tender and delicate substance of the brain and spinal cord1 the central seat of the animal life1 with which all the senses are in intimate communion1 is protected by bones and muscles which perform important voluntary movements while the organs of sense which put us in connexion with the external world1 which render us susceptible of pleasure1 and which give us notice of the approach of objects capable of exciting pain1 are placed where external bodies may be brought most conveniently and completely into contact with them2 and where alone they can be efficient as the sentinels of the system4 ,for this reason1 with the exception of the sense of touch1 which1 though placed especially at the extremities of the fingers1 is also diffused over the whole external surface of the frame1 all the senses have their several seats in the head1 the most elevated part of the body1 of an ovoid figure1 capable of moving independently of the rest of the fabric1 and which1 being supported on a pivot1 is enabled to describe at least two-thirds of a circle4 ,such is the difference in the structure and position of the apparatus of the two lives1 but the difference in their action is still more striking4 #a4 ,the action of the apparatus of the organic life when sound is without consciousness2 the object of the action of the apparatus of the animal life is the production of consciousness4 ,the final cause of the action of the apparatus of the organic life is the maintenance of existence2 the final cause of the action of the apparatus of the animal life is the production of conscious existence4 ,what purpose would be answered by connecting consciousness with the action of the organic organs8 ,were we sensible of the organic processes2 did we know when the heart beats1 and the lung plays1 and the stomach digests1 and the excretory organ excretes1 the consciousness could not promote1 but might disturb the due and orderly course of these processes4 ,moreover they would so occupy and engross our minds that we should have little inclination or time to attend to other objects4 ,beneficently therefore are they placed equally beyond our observation and control4 ,nevertheless1 when our consciousness of these processes may be of service2 when they are going wrong2 when their too feeble or too intense action is in danger of destroying existence1 the animal life is made sensible of what is passing in the organic1 in order that the former may take beneficial cognizance of the latter1 may do what experience may have taught to be conducive to the restoration of the diseased organ to a sound state1 or avoid doing what may conduce to the increase or maintenance of its morbid condition4 ,but while the action of the organic organs is thus kept alike from our view and feeling1 the sole object of the action of the animal organs is to produce and maintain a state of varied and extended consciousness4 ,we do not know when the heart dilates to receive the vital current1 nor when it contracts to propel it with renewed impetus through the system2 nor when the blood rushes to the lung to give out its useless and noxious particles2 nor when the air rushes to the blood to take up those particles1 to replace them by others1 and thus to purify and renovate the vital fluid4 ,many processes of this kind are continually going on within us during every moment of our existence1 but we are no more conscious of them than we are of the motion of the fluids in the blade of grass on which we tread4 ,on the contrary when an external object produces1 in a sentient nerve1 that change of state which we denote by the words an impression2 when the sentient nerve transmits this impression to the brain2 when the brain is thereby brought into the state of perception1 the animal life is in active operation1 and percipient or conscious existence takes place4 ,consciousness does not belong to the organic1 it is the animal life4 #b4 ,the functions of the organic life are performed with uninterrupted continuity2 to those of the animal life rest is indispensable4 ,the action of the heart is unceasing2 it takes not and needs not rest4 ,on it goes1 for the space of eighty or ninety years1 at the rate of a hundred thousand strokes every twenty-four hours1 having at every stroke a great resistance to overcome1 yet it continues this action for this length of time without intermission4 ,alike incessant is the action of the lung1 which is always receiving and always emitting air2 and the action of the skin1 which is always transpiring and always absorbing2 and the action of the alimentary canal1 which is always compensating the loss which the system is always sustaining4 ,but of this continuity of action the organs and functions of the animal life are incapable4 ,no voluntary muscle can maintain its action beyond a given time2 no effort of the will can keep it in a state of uninterrupted contraction2 relaxation must alternate with contraction2 and even this alternate action cannot go on long without rest4 ,no organ of sense can continue to receive impression after impression without fatigue4 ,by protracted exertion the ear loses its sensibility to sound1 the eye to light1 the tongue to savour1 and the touch to the qualities of bodies about which it is conversant4 ,the brain cannot carry on its intellectual operations with vigour beyond a certain period2 the trains of ideas with which it works become1 after a time1 indistinct and confused2 nor is it capable of reacting with energy until it has remained in a state of rest proportioned to the duration of its preceding activity4 ,and this rest is sleep4 ,sleep is the repose of the senses1 the rest of the muscles1 their support and sustenance4 ,what food is to the organic1 sleep is to the animal life4 ,nutrition can no more go on without aliment1 than sensation1 thought1 and motion without sleep4 ,but it is the animal life only that sleeps3 death would be the consequence of the momentary slumber of the organic4 ,if1 when the brain betook itself to repose1 the engine that moves the blood ceased to supply it with its vital fluid1 never again would it awake4 ,the animal life is active only during a portion of its existence2 the activity of the organic life is never for a moment suspended2 and in order to endow its organs with the power of continuing this uninterrupted action1 they are rendered incapable of fatigue3 fatigue1 on the contrary1 is inseparable from the action of the organs of the animal life2 fatigue imposes the necessity of rest1 rest is sleep1 and sleep is renovation4 #c4 ,between all the functions of the organic life there is a close relation and dependence4 ,without the circulation there can be no secretion2 without secretion1 no digestion2 without digestion1 no nutrition2 without nutrition1 no new supply of circulating matter1 and so through the entire circle4 ,but the functions of the animal life are not thus dependent on each other4 ,one of the circle may be disordered without much disturbance of the rest2 and one may cease altogether1 while another continues in vigorous action4 ,sensation may be lost1 while motion continues2 and the muscle may contract though it cannot feel4 ,one organ of sense may sleep while the rest are awake4 ,one intellectual faculty may be in operation while others slumber4 ,the muscle of volition may act1 while there is no consciousness of will4 ,even the organs of the voice and of progression may perform their office while the sensorium is deeply locked in sleep4 #d4 ,the two lives are born at different periods1 and the one is in active operation before the other is even in existence4 ,the first action observable in the embryo is a minute pulsating point4 ,it is the young heart propelling its infant stream4 ,before brain1 or nerve1 or muscle can be distinguished1 the heart is in existence and in action2 that is1 the apparatus of the organic function of the circulation is built up and is in operation before there is any trace of an animal organ4 ,arteries and veins circulate blood1 capillary vessels receive the vital fluid1 and out of it form brain and muscle1 the organs of the animal1 no less than the various substances that compose the organs of the organic life4 ,the organic is not only anterior to the animal life1 but it is by the action of the organic that existence is given to the animal life4 ,the organic life is born at the first moment of existence2 the animal life not until a period comparatively distant2 the epoch emphatically called the period of birth1 namely1 the period when the new being is detached from its mother2 when it first comes into contact with external objects2 when it carries on all the functions of its economy by its own organs1 and consequently enjoys independent existence4 #e4 ,the functions of the organic life are perfect at once4 ,the heart contracts as well1 the arteries secrete as well1 the respiratory organs work as well the first moment they begin to act as at any subsequent period4 ,they require no teaching from experience1 and they profit nothing from its lessons4 ,on the contrary1 the operations of the brain1 and the actions of the voluntary muscles1 feeble and uncertain at first1 acquire strength by slow degrees1 and attain their ultimate perfection only at the adult age4 ,how indistinct and confused the first sensations of the infant6 ,before it acquire accuracy1 precision1 and truth1 how immense the labour spent upon perception6 ,sensations are succeeded by ideas2 sensations and ideas coalesce with sensations and ideas2 combinations thus formed suggest other combinations previously formed1 and these a third1 and the third a fourth1 and so is constituted a continuous train of thought4 ,but the infantile associations between sensation and sensation1 between idea and idea1 and between sensations and ideas1 are1 to a certain extent1 incorrect1 and to a still greater extent inadequate2 and the misconception necessarily resulting from this early imperfection in the intellectual operations is capable of correction only by subsequent and more extended impressions4 ,during its making hours1 a large portion of the time of the infant is spent in receiving impressions which come to it every instant from all directions1 and which it stores up in its little treasury2 but a large portion is also consumed in the far more serious and difficult business of discrimination and correction4 ,could any man1 after having attained the age of manhood1 reverse the order of the course through which he has passed2 could he1 with the power of observation1 together with the experience that belong to manhood1 retrace with perfect exactness every step of his sentient existence1 from the age of forty to the moment that the air first came into contact with his body at the moment of his leaving his maternal dwelling1 among the truths he would learn1 the most interesting1 if not the most surprising1 would be those which relate to the manner in which he dealt with his earliest impressions2 with the mode in which he combined them1 recalled them1 laid them by for future use2 made his first general deduction2 observed what subsequent experience taught to be conformable1 and what not conformable1 to this general inference2 his emotions on detecting his first errors1 and his contrasted feelings on discovering those comprehensive truths1 the certainty of which became confirmed by every subsequent impression4 ,thus to live backwards would be1 in fact1 to go through the analysis of the intellectual combinations1 and1 consequently1 to obtain a perfect insight into the constitution of the mind2 and among the curious results which would then become manifest1 perhaps few would appear more surprising than the true action of the senses4 ,the eye1 when first impressed by light1 does not perceive the objects that reflect it2 the ear1 when first impressed by sound1 does not distinguish the sonorous body4 ,when the operation for cataract has been successfully performed in a person born blind1 the eye immediately becomes sensible to light1 but the impression of light does not immediately give information relative to the properties of bodies4 ,it is gradually1 not instantaneously2 it is even by slow degrees that luminous objects are discerned with distinctness and accuracy4 ,to see1 to hear1 to smell1 to taste1 to touch1 are processes which appear to be performed instantaneously1 and which actually are performed with astonishing rapidity in a person who observes them in himself2 but they were not always performed thus rapidly3 they are processes acquired1 businesses learnt2 processes and businesses acquired and learnt1 not without the cost of many efforts and much labour4 ,but the senses afford merely the materials for the intellectual operations of memory1 combination1 comparison1 discrimination1 induction1 operations the progress of which is so slow1 that they acquire precision1 energy1 and comprehensiveness only after the culture of years4 ,and the same is true of the muscles of volition4 ,how many efforts are made before the power of distinct articulation is acquired6 how many before the infant can stand6 how many before the child can walk6 ,the organic life is born perfect2 the animal life becomes perfect only by servitude1 and the aptitude which service gives4 #f4 ,the organic life may exist after the animal life has perished4 ,the animal life is extinguished when sensation is abolished1 and voluntary motion can be performed no more4 ,but disease may abolish sensation and destroy the power of voluntary motion1 while circulation1 respiration1 secretion1 excretion1 in a word1 the entire circle of the organic functions continues to be performed4 ,in a single instant apoplexy may reduce to drivelling fatuity the most exalted intellect1 and render powerless and motionless muscles of gigantic strength2 while the action of the heart and the involuntary contractions of the muscles may not only not be weakened1 but may act with preternatural energy4 ,in a single instant1 apoplexy may even completely extinguish the animal life1 and yet the organic may go on for hours1 days1 and even weeks2 while catalepsy1 perhaps the most singular disease to which the human frame is subject1 may wholly abolish sensation and volition1 while it may impart to the voluntary muscles the power of contracting with such unnatural energy and continuity1 that the head1 the trunk1 the limbs may become immoveably fixed in whatever attitude they happen to be at the moment the paroxysm comes on4 ,in this extraordinary condition of the nervous system1 however long the paroxysm last1 and however complete the abolition of consciousness1 the heart continues to beat1 and the pulse to throb1 and the lungs to respire1 and all the organic organs to perform their ordinary functions4 ,dr4 ,jebb gives the following description of the condition of a young lady who was the subject of this curious malady4 ,my patient was seized with an attack just as ,i was announced4 ,at that moment she was employed in netting2 she was in the act of passing the needle through the mesh2 in that position she became immoveably rigid1 exhibiting1 in a pleasing form1 a figure of death-like sleep1 beyond the power of art to imitate1 or the imagination to conceive4 ,her forehead was serene1 her features perfectly composed4 ,the paleness of her colour1 and her breathing1 which at a distance was scarcely perceptible1 operated in rendering the similitude to marble more exact and striking4 ,the position of her fingers1 hands1 and arms was altered with difficulty1 but preserved every form of flexure they acquired3 nor were the muscles of the neck exempted from this law1 her head maintaining every situation in which the hand could place it1 as firmly as her limbs4 ,in this condition of the system the senses were in a state of profound sleep2 the voluntary muscles1 on the contrary1 were in a state of violent action2 but this action not being excited by volition1 nor under its control1 the patient remained as motionless as she was insensible4 ,the brain was in a state of temporary death2 the muscle in a state of intense life4 ,and the converse may happen3 the muscle may die1 while the brain lives2 contractility may be destroyed1 while sensibility is perfect2 the power of motion may be lost1 while that of sensation may remain unaffected4 ,a case is on record1 which affords an illustration of this condition of the system4 ,a woman had been for some time confined to her bed1 labouring under severe indisposition4 ,on a sudden she was deprived of the power of moving a single muscle of the body2 she attempted to speak1 but she had no power to articulate2 she endeavoured to stretch out her hand1 but her muscles refused to obey the commands of her will1 yet her consciousness was perfect1 and she retained the complete possession of her intellectual faculties4 ,she perceived that her attendants thought her dead1 and was conscious of the performance upon her own person of the services usually paid to the dead2 she was laid out1 her toes were bound together1 her chin was tied up2 she heard the arrangements for her funeral discussed1 and yet she was unable to make the slightest sign that she was still in the possession of sense1 feeling1 and life4 ,in one form of disease1 then1 the animal life1 both the sensitive and the motive portions of it1 may perish2 and in another form of disease1 either the one or the other part of it may be suspended1 while the organic life continues in full operation3 it follows that the two lives1 blended as they are1 are distinct1 since the one is capable of perishing without immediately and inevitably involving the destruction of the other4 #g4 ,and1 finally1 as the organic life is the first born1 so it is the last to die2 while the animal life1 as it is the latest born1 and the last to attain its full development1 so it is the earliest to decline and the first to perish4 ,in the process of natural death1 the extinction of the animal is always anterior to that of the organic life4 ,real death is a later1 and sometimes a much later event than apparent death4 ,an animal appears to be dead when1 together with the abolition of sensation and the loss of voluntary motion1 respiration1 circulation1 and the rest of the organic functions can no longer be distinguished2 but these functions go on some time after they have ceased to afford external indications of their action4 ,in man1 and the warmblooded animals in general1 suspension or submersion extinguishes the animal life1 at the latest1 within the space of four minutes from the time that the atmospheric air is completely excluded from the lung2 but did the organic functions also cease at the same period1 it would be impossible to restore an animal to life after apparent death from drowning and the like4 ,but however complete and protracted the abolition of the animal functions1 re-animation is always possible as long as the organic organs are capable of being restored to their usual vigour4 ,the cessation of the animal life is but the first stage of death1 from which recovery is possible2 death is complete only when the organic together with the animal functions have wholly ceased1 and are incapable of being re-established4 ,in man1 the process of death is seldom altogether natural4 ,it is generally rendered premature by the operation of circumstances which destroy life otherwise than by that progressive and slow decay which is the inevitable result of the action of organized structure4 ,death1 when natural1 is the last event of an extended series1 of which the first that is appreciable is a change in the animal life and in the noblest portion of that life4 ,the higher faculties fail in the reverse order of their development2 the retrogression is the inverse of the progression1 and the noblest creature1 in returning to the state of non-existence1 retraces step by step each successive stage by which it reached the summit of life4 ,in the advancing series1 the animal is superadded to the organic life2 sensation1 the lowest faculty of the animal life1 precedes ratiocination1 the highest4 ,the senses called into play at the moment of birth soon acquire the utmost perfection of which they are capable2 but the intellectual faculties1 later developed1 are still later perfected1 and the highest the latest4 ,in the descending series1 the animal life fails before the organic1 and its nobler powers decay sooner and more rapidly than the subordinate4 ,first of all1 the impressions which the organs of sense convey to the brain become less numerous and distinct1 and consequently the material on which the mind operates is less abundant and perfect2 but at the same time1 the power of working vigorously with the material it possesses more than proportionally diminishes4 ,memory fails2 analogous phenomena are less readily and less completely recalled by the presence of those which should suggest the entire train2 the connecting links are dimly seen or wholly lost2 the train itself is less vivid and less coherent2 train succeeds train with preternatural slowness1 and the consequence of these growing imperfections is that1 at last1 induction becomes unsound just as it was in early youth2 and for the same reason1 namely1 because there is not in the mental view an adequate range of individual phenomena2 the only difference being that the range comprehended in the view of the old man is too narrow1 because that which he had learnt he has forgotten2 while in the youth it is too narrow1 because that which it is necessary to learn has not been acquired4 ,and with the diminution of intellectual power the senses continue progressively to fail3 the eye grows more dim1 the ear more dull1 the sense of smell less delicate1 the sense of touch less acute1 while the sense of taste immediately subservient to the organic function of nutrition is the last to diminish in intensity and correctness1 and wholly fails but with the extinction of the life it serves4 ,but the senses are not the only servants of the brain2 the voluntary muscles are so equally2 but these ministers to the master-power1 no longer kept in active service1 the former no longer employed to convey new1 varied1 and vivid impressions1 the latter no longer employed to execute the commands of new1 varied1 and intense desires1 become successively feebler1 slower1 and more uncertain in their action4 ,the hand trembles1 the step totters1 and every movement is tardy and unsteady4 ,and thus1 by the loss of one intellectual faculty after another1 by the obliteration of sense after sense1 by the progressive failure of the power of voluntary motion2 in a word1 by the declining energy and the ultimate extinction of the animal life1 man1 from the state of maturity1 passes a second time through the stage of childhood back to that of infancy2 lapses even into the condition of the embryo3 what the ftus was1 the man of extreme old age is3 when he began to exist1 he possessed only organic life2 and before he is ripe for the tomb1 he returns to the condition of the plant4 ,and even this merely organic existence cannot be long maintained4 ,slow may be the waste of the organic organs2 but they do waste1 and that waste is not repaired1 and consequently their functions languish1 and no amount of stimulus is capable of invigorating their failing action4 ,the arteries are rigid and cannot nourish2 the veins are relaxed and cannot carry on the mass of blood that oppresses them2 the lungs1 partly choked up by the deposition of adventitious matter1 and partly incapable of expanding and collapsing by reason of the feeble action of the respiratory apparatus1 imperfectly arate the small quantity of blood that flows through them2 the heart1 deprived of its wonted nutriment and stimulus1 is unable to contract with the energy requisite to propel the vital current2 the various organs1 no longer supplied with the quantity and quality of material necessary for carrying on their respective processes1 cease to act2 the machinery stops1 and this is death4 ,and now the processes of life at an end1 the body falls within the dominion of the powers which preside universally over matter2 the tie that linked all its parts together1 holding them in union and keeping them in action1 in direct opposition to those powers dissolved1 it feels and obeys the new attractions to which it has become subject2 particle after particle that stood in beautiful order fall from their place2 the wonderful structures they composed melt away2 the very substances of which those structures were built up are resolved into their primitive elements2 these elements1 set at liberty1 enter into new combinations1 and become constituent parts of new beings2 those new beings in their turn perish2 from their death springs life1 and so the changes go on in an everlasting circle4 ,as far as relates to the organized structures in which life has its seat1 and to the operations of life dependent on those structures1 such is its history2 a history not merely curious1 but abounding with practical suggestions of the last importance4 ,the usefulness of a familiar acquaintance with the phenomena which have now been elucidated will be apparent at every step as we proceed4 ,,chapter ,,iii4 ,ultimate object of organization and life--,sources of pleasure--,special provision by which the organic organs influence consciousness and afford pleasure--,point at which the organic organs cease to affect consciousness1 and why--,the animal appetites3 the senses3 the intellectual faculties3 the selfish and sympathetic affections3 the moral faculty--,pleasure the direct1 the ordinary1 and the gratuitous result of the action of the organs--,pleasure conducive to the development of the organs1 and to the continuance of their action--,progress of human knowledge--,progress of human happiness4 ,the object of structure is the production of function4 ,of the two functions combined in the living animal1 one is wholly subservient to the other4 ,to build up the apparatus of the animal life1 and to maintain it in a condition fit for performing its functions1 is the sole object of the existence of the organic life4 ,what then is the object of the animal life8 ,that object1 whatever it be1 must be the ultimate end of organization1 and of all the actions of which it is the seat and the instrument4 ,two functions1 sensation and voluntary motion1 are combined in the animal life4 ,of these two functions1 the latter is subservient to the former3 voluntary motion is the servant of sensation1 and exists only to obey its commands4 ,is sensation1 then1 the ultimate object of organization8 ,simple sensation cannot be an ultimate object1 because it is invariably attended with an ultimate result2 for sensation is either pleasurable or painful4 ,every sensation terminates in a pleasure or a pain4 ,pleasure or pain1 the last event in the series1 must then be the final end4 ,is the production of pain the ultimate object of organization8 ,that cannot be1 for the production of pain is the indirect1 not the direct1--the extraordinary1 not the ordinary1 result of the actions of life4 ,it follows that pleasure must be the ultimate object1 for there is no other of which it is possible to conceive4 ,the end of organic existence is animal existence2 the end of animal existence is sentient existence2 the end of sentient existence is pleasurable existence2 the end of life therefore is enjoyment4 ,life commences with the organic processes2 to the organic are superadded the animal2 the animal processes terminate in sensation2 sensation ends in enjoyment2 it follows1 that enjoyment is the final end4 ,for this every organ is constructed2 to this every action of every organ is subservient2 in this every action ultimately terminates4 ,and without a single exception in the entire range of the sentient creation1 the higher the organized structure the greater the enjoyment1 mediately or immediately1 to which it is subservient4 ,from its most simple to its most complex state1 every successive addition to structure1 by which function is rendered more elevated and perfect1 proportionally increases the exquisiteness of the pleasure to which the function ministers1 and in which it terminates4 ,pleasure is the result of the action of living organs1 whether organic or animal2 pleasure is the direct1 the ordinary1 and the gratuitous result of the action of both sets of organs2 the pleasure resulting from the action of the organs is conducive to their complete development1 and thereby to the increase of their capacity for affording enjoyment2 the pleasure resulting from the action of the organs1 and conducive to their development1 is equally conducive to the perpetuation of their action1 and consequently to the maintenance of life2 it follows not only that enjoyment is the end of life1 but that it is the means by which life is prolonged4 ,of the truth of each of these propositions1 it will be interesting to contemplate the plenitude of the proof4 #a4 ,in the first place1 pleasure is the result of the action of the organic organs4 ,it has indeed been shown that the very character by which the action of these organs is distinguished is that they are unattended with consciousness4 ,nevertheless1 by a special provision1 consciousness is indirectly connected with the processes of this class1 limited in extent indeed1 and uniformly terminating at a certain point2 but the extent and the limitation alike conducing to the pleasurableness of its nature4 ,and this is an adjustment in the constitution of our frame which is well deserving of attention4 ,organic processes are dependent on a peculiar influence derived from that portion of the nervous system distinguished by the term organic4 ,the organic nerves1 distributed to the organic organs1 take their origin and have their chief seat in the cavities that contain the main instruments of the organic life1 namely1 the chest and abdomen 7see chap4 v474 ,as will be fully shown hereafter1 these nerves encompass the great trunks of the blood-vessels that convey arterial blood to the organic organs4 ,in all its ramifications through an organic organ1 an arterial vessel is accompanied by its organic nerve2 so that wherever the capillary arterial branch goes1 secreting or nourishing1 there goes1 inseparably united with it1 an organic nerve1 exciting and governing4 ,among the peculiarities of this portion of the nervous system1 one of the most remarkable is1 that it is wholly destitute of feeling4 ,sensibility is inseparably associated with the idea commonly formed of a nerve4 ,but the nervous system consists of two portions1 one presiding over sensation and voluntary motion1 hence called the sentient and the motive portions2 the other destitute of sensation1 but presiding over the organic processes1 hence called the organic portion4 ,if the communication between the organic organ and the organic nerve be interrupted1 the function of the organ1 whatever it be1 is arrested4 ,without its organic nerves1 the stomach cannot secrete gastric juice2 the consequence is1 that the aliment is undigested4 ,without its organic nerves1 the liver cannot secrete bile1 the consequence is1 that the nutritive part of the aliment is incapable of being separated from its excrementitious portion4 ,the organic organ receives from its organic nerve an influence1 without which it cannot perform its function2 but the nerve belonging to this class neither feels nor communicates feeling1 and hence it imparts no consciousness of the operation of any process dependent upon it4 ,yet there is not one of these processes that does not exert a most important influence over consciousness4 ,how8 ,by a special provision1 as curious in its nature as it is important in its result4 ,branches of sentient nerves are transmitted from the animal to the organic system1 and from the organic to the animal2 and an intimate communication is established between the two classes4 ,the inspection of fig4 ,,xvi4 will illustrate the mode in which this communication is effected4 ,a ,b represents a portion of the spinal cord 7one of the central masses of the sentient system71 covered with its membranes4 ,the part here represented is a front view of that portion of the spinal cord which belongs to the back1 and which is technically called the dorsal portion4 ,illustration3 ,fig4 ,,xvi4 #a1 #b1 #c1 #d1 #e1 #f1 #g1 #h1 #i1 the second1 c4 ribs with the corresponding dorsal 7sentient7 nerves1 a1 b1 c1 d1 e1 f1 g1 h1 going out to supply their respective organs with sensation4 ,c ,d ,e1 a portion of the main trunk of the organic 7non-sentient7 nerve1 commonly called the ,great ,sympathetic4 ,f ,g ,h1 the membrane of the spinal cord cut open and exposing ,i ,k1 the spinal cord itself1 ,l1 the anterior branch of one of the dorsal nerves1 arising from the anterior surface of the spinal cord by several bundles of fibres4 ,m1 the posterior branch of the same nerve1 arising in like manner from the posterior surface of the spinal cord by several branches of fibres4 ,the anterior and posterior branches uniting to form one trunk ,n4 ,two branches1 ,p ,q1 sent off from the spinal 7sentient7 trunk to unite with the organic 7non-sentient7 trunk4 ,r ,s ,t ,u ,v ,w1 other branches of the sentient1 connected with the branches of the non-sentient nervous trunks in the same mode4 ,x ,y1 the main trunk of the sympathetic 7non-sentient7 nerve cut across and turned aside1 in order that the parts beneath it 7,p ,n7 may be more distinctly seen4 ,from this description1 it is apparent that each sentient nerve1 before it goes out to the animal organs1 to which it is destined to communicate sensation1 sends off two branches to the organic or the non-sentient4 ,these sentient nerves mix and mingle with the insensible nerves2 accompany them in their course to the organic organs1 and ramify with them throughout their substance4 ,it is manifest1 then1 that sentient nerves1 that nerves not necessary to the organic processes1 having1 as far as is known1 nothing whatever to do with those processes1 enter as constituent parts into the composition of the organic organs4 ,what is the result8 ,that organic organs are rendered sentient2 that organic processes1 in their own nature insensible1 become capable of affecting consciousness4 ,what follows8 ,what is the consciousness excited8 ,not a consciousness of the organic process4 ,of that we still remain wholly insensible4 ,not simple sensation4 ,the result uniformly produced1 as long as the state of the system is that of health1 is pleasurable consciousness4 ,the heart sends out to the organs its vital current4 ,each organ1 abstracting from the stream the particles it needs1 converts them into the peculiar fluid or solid it is its office to form4 ,the stomach1 from the arterial streamlets circulating through it1 secretes gastric juice2 the liver1 from the venous streamlets circulating through it1 secretes bile4 ,when these digestive organs have duly prepared their respective fluids1 they employ them in the elaboration of the aliment4 ,we are not conscious of this elaboration1 though it go on within us every moment2 but is consciousness not affected by the process8 ,most materially4 ,why8 ,because sentient mingle with organic nerves2 because the sentient nerves are impressed by the actions of the organic organs4 ,and how impressed8 ,as long as the actions of the organic organs are sound1 that is1 as long as their processes are duly performed1 the impression communicated to the sentient nerves is in its nature agreeable2 is1 in fact1 ,,the ,,pleasurable ,,consciousness ,,which ,,constitutes ,,the ,,feeling ,,of ,,health4 ,the state of health is nothing but the result of the due performance of the organic organs3 it follows that the feeling of health1 the feeling which is ranked by every one among the most pleasurable of existence1 is the result of the action of organs of whose direct operations we are unconscious4 ,but the pleasurable consciousness thus indirectly excited is really the consequence of a special provision1 established for the express purpose of producing pleasure4 ,processes1 in their own nature insensible1 are rendered sentient expressly for this purpose1 that1 over and above the special object they serve1 they may afford enjoyment4 ,in this case1 the production of pleasure is not only altogether gratuitous1 not only communicated for its own sake1 not only rested in as an ultimate object1 but it is made to commence at the very confines of life2 it is interwoven with the thread of existence3 it is secured in and by the actions that build up and that support the very framework1 the material instrument of our being4 ,but if the communication of sensibility to processes in their own nature incapable of exciting feeling1 for the purpose of converting them into sources of pleasurable consciousness1 indicate an express provision for the production of enjoyment1 that provision is no less exemplified in the point at which this superadded sensibility is made to cease4 ,some of the consequences of a direct communication of consciousness to an organic process have been already adverted to4 ,had the eye1 besides transmitting rays of light to the optic nerve1 been rendered sensible of the successive passage of each ray through its substance1 the impression excited by luminous bodies1 which is indispensable to vision1 the ultimate object of the instrument1 if not wholly lost1 must necessarily have become obscure1 in direct proportion to the acuteness of this sensibility4 ,the hand of the musician could scarcely have executed its varied and rapid movements upon his instrument1 had his mind been occupied at one and the same instant with the process of muscular contraction in the finger1 and the idea of music in the brain4 ,had the communication of such a twofold consciousness been possible1 in no respect would it have been beneficial1 in many it would have been highly pernicious2 and the least of the evils resulting from it would have been1 that the inferior would have interrupted the superior faculty1 and the means deteriorated the end4 ,but in some cases the evil would have been of a much more serious nature4 ,had we been rendered sensible of the flow of the vital current through the engine that propels it2 were the distension of the delicate valves that direct the current ever present to our view2 by some inward feeling were we reminded1 minute by minute1 of the progress of the aliment through the digestive apparatus1 and were the mysterious operations of the organic nerves palpable to sight1 the terror of the maniac1 who conceived that his body was composed of unannealed glass1 would be the ordinary feeling of life4 ,every movement would be a matter of anxious deliberation2 and the approach of every body to our own would fill us with dismay4 ,but adjusted as our consciousness actually is1 invariably the point at which the organic process begins is that at which sensation ends4 ,had sensation been extended beyond this point1 it would have been productive of pain3 at this point it uniformly stops4 ,nevertheless1 by the indirect connexion of sensation with the organic processes1 a vast amount of pleasure might be created3 a special apparatus is constructed for the express purpose of establishing the communication4 ,there is thus the twofold proof1 the positive and the negative1 the evidence arising as well from what they do1 as from what they abstain from doing1 that the organic processes are1 and are intended to be1 sources of enjoyment4 ,but the production of pleasure1 commencing at this the lowest point of conscious existence1 increases with the progressive advancement of organization and function4 ,the appetite for food1 and the voluntary actions dependent upon it1 may be considered as the first advancement beyond a process purely organic4 ,the function by which new matter is introduced into the system and converted into nutriment1 is partly an animal and partly an organic operation4 ,the animal part of it consists of the sensations of hunger and thirst1 by which we are taught when the wants of the system require a fresh supply of aliment1 together with the voluntary actions by which the aliment is introduced into the system4 ,the organic part of the function consists of the changes which the aliment undergoes after its introduction into the system1 by which it is converted into nutriment4 ,sensations always of a pleasurable nature arise indirectly in the manner already explained1 from the due performance of the organic part of the function2 but pleasure is also directly produced by the performance of the animal part of it4 ,wholesome food is grateful2 the satisfaction of the appetite for food is pleasurable4 ,food is necessary to the support of life2 but it is not indispensable to the maintenance of life that food should be agreeable4 ,appetite there must be1 that food may be eaten2 but the act of eating might have been secured without connecting it with pleasure4 ,pleasure1 however1 is connected with it1 first directly1 by the gratefulness of food1 and secondly indirectly1 by the due digestion of the food4 ,and the annexation of pleasure in this twofold mode to the performance of the function of nutrition is another case of the gratuitous bestowment of pleasure2 another instance in which pleasure is communicated for its own sake1 and rested in as an ultimate object4 ,pleasures of this class are sometimes called low2 they are comparatively low2 but they are not the less pleasures1 because they are exceeded in value by pleasures of a nobler nature4 ,man may regard them with comparative indifference1 because he is endowed with faculties which afford him gratifications superior in kind and larger in amount2 but it is no mark of wisdom to despise and neglect even these3 for they are annexed to the exercise of a function which is the first to exalt us above a merely organic existence2 they are the first pleasures of which1 considered merely as sentient creatures1 we are susceptible2 they amount in the aggregate to an immense sum2 and they mark the depth in our nature in which are laid the fountains of enjoyment4 ,organs of sense1 intellectual faculties1 social affections1 moral powers1 are superadded endowments of a successively higher order3 at the same time1 they are the instruments of enjoyment of a nature progressively more and more exquisite4 ,an organ of sense is an instrument composed of a peculiar arrangement of organized matter1 by which it is adapted to receive from specific agents definite impressions4 ,between the agent that produces and the organ that receives the impression1 the adaptation is such1 that the result of their mutual action is1 in the first place1 the production of sensation1 and1 in the second place1 the production of pleasure4 ,the pleasure is as much the result as the sensation4 ,this is true of the eye in seeing1 the ear in hearing1 the hand in touching1 the organ of smell in smelling1 and the tongue in tasting4 ,pleasure is linked with the sense2 but there might have been the sense without the pleasure4 ,a slight difference in the construction of the organ1 or in the intensity of the agent1 would not merely have changed1 it would even have reversed the result2 would have rendered the habitual condition of the eye1 the ear1 the skin1 not such as it now is in health1 but such as it is in the state of inflammation4 ,but the adjustment is such as habitually to secure that condition of the system in which every action that excites sensation produces pleasure as its ordinary concomitant2 and the amount of enjoyment which is thus secured to every man1 and which every man without exception actually experiences in the ordinary course of an ordinary life1 it would be beyond his power to estimate were he always sensible of the boon2 but the calculation is altogether impossible1 when1 as is generally the case1 he merely enjoys without ever thinking of the provisions which enable him to do so4 ,but if the pleasures that arise from the ordinary operations of sense form1 in the aggregate1 an incalculable sum1 how great is the accession brought to this stock by the endowments next in order in the ascending scale1 namely1 the intellectual faculties6 ,there is one effect resulting from the operation of the intellectual faculties on the senses that deserves particular attention4 ,the higher faculties elevate the subordinate in such a manner as to make them altogether new endowments4 ,in illustration of this1 it will suffice to notice the change wrought1 as if in the very nature of sensation1 the moment it becomes combined with an intellectual operation1 as exemplified in the difference between the intellectual conception of beauty1 and the mere perception of sense4 ,the grouping of the hills that bound that magnificent valley which ,i behold at this moment spread out before my view2 the shadow of the trees at the base of some of them1 stretching its deep and varied outline up the sides of others2 the glancing light now brightening a hundred different hues of green on the broad meadows1 and now dancing on the upland fallows2 the ever-moving1 ever-changing clouds2 the scented air2 the song of birds2 the still more touching music which the breeze awakens in the scarcely trembling branches of those pine trees1--the elements of which this scene is composed1 the mere objects of sense1 the sun1 the sky1 the air1 the hills1 the woods1 and the sounds poured out from them1 impress the senses of the animals that graze in the midst of them2 but on their senses they fall dull and without effect1 exciting no perception of their loveliness1 and giving no taste of the pleasures they are capable of affording4 ,nor even in the human being1 whose intellectual faculties have been uncultivated1 do they awaken either emotions or ideas2 the clown sees them1 hears them1 feels them no more than the herds he tends3 yet in him whose mind has been cultivated and unfolded1 how numerous and varied the impressions1 how manifold the combinations1 how exquisite the pleasures produced by objects such as these6 ,and from the more purely intellectual operations1 from memory1 comparison1 analysis1 combination1 classification1 induction1 how still nobler the pleasure6 ,not to speak of the happiness of him who1 by his study of natural phenomena1 at length arrived at the stupendous discovery that the earth and all the stars of the firmament move1 and that the feather falls to the ground1 by the operation of one and the same physical law2 nor of the happiness of him who sent his kite into the cloud1 and brought down from its quiet bed the lightning which he suspected was slumbering there2 nor of the happiness of him who concentrated1 directed1 and controlled that mighty power which has enabled the feeble hand of man to accomplish works greater than have been feigned of fabled giant2 which has annihilated distance2 created1 by economizing time2 changed in the short space in which it has been in operation the surface of the habitable globe2 and is destined to work upon it more and greater changes than have been effected by all other causes combined2 nor of the happiness of him who devoted a longer life with equal success to a nobler labour1 that of ,,rearing ,,the ,,fabric ,,of ,,felicity ,,by ,,the ,,hand ,,of ,,reason ,,and ,,of ,,law4 ,the intellectual pleasures of such men as ,newton1 ,franklin1 ,watt1 and ,bentham1 can be equalled only by those who possess equal intellectual power1 and who put forth equal intellectual energy3 to be greatly happy as they were1 it were necessary to be as highly endowed2 but to be happy1 it is not necessary to be so endowed4 ,in the ordinary intellectual operations of ordinary men1 in their ordinary occupations1 there is happiness4 ,every human being whose moments have passed with winged speed1 whose day has been short1 whose year is gone almost as soon as it seemed commenced1 has derived from the exercise of his intellectual faculties pleasures countless in number and inestimable in value4 ,but the sympathetic pleasures1 out of which grow the social1 are of a still higher order even than the intellectual4 ,the pleasures that result from the action of the organic organs1 from the exercise of the several senses1 and from the operation of the intellectual faculties1 like the sensations in which they arise1 belong exclusively to the individual being that experiences them1 and cannot be communicated to another4 ,similar sensations and pleasures may be felt by beings similarly constituted2 but the actual sensations and pleasures afforded by the exercise of a person's own organs and faculties are no more capable of becoming another's than his existence4 ,these1 then1 are strictly the selfish pleasures2 and the provision that has been made for securing them has been shown4 ,but there are pleasures of another class1 pleasures having no relation whatever to a person's own sensation or happiness2 pleasures springing from the perception of the enjoyment of others4 ,the sight of pleasure not its own affects the human heart1 provided its state of feeling be natural and sound1 just as it would be affected were it its own4 ,not more real is the pleasure arising from the gratification of appetite1 the exercise of sense1 and the operation of intellect1 than that arising from the consciousness that another sentient being is happy4 ,pleasures of this class are called sympathetic1 in contradistinction to those of the former class1 which are termed selfish4 ,there are then two principles in continual operation in the human being1 the selfish and the sympathetic4 ,the selfish is productive of pleasure of a certain kind2 the sympathetic is productive of pleasure of another kind4 ,the selfish is primary and essential2 the sympathetic1 arising out of the selfish1 is superadded to it4 ,and so precisely what the animal life is to the organic1 the sympathetic principle is to the selfish2 and just what the organic life gains by its union with the animal1 the mental constitution gains by the addition of the sympathetic to the selfish affection4 ,the analogy between the combination in both cases is in every respect complete4 ,as the organic life produces and sustains the animal1 so the sympathetic principle is produced and sustained by the selfish4 ,as the organic life is conservative of the entire organization of the body1 so the selfish principle is conservative of the entire being4 ,as the animal life is superadded to the organic1 extending1 exalting1 and perfecting it1 so the sympathetic principle is superadded to the selfish1 equally extending1 exalting1 and perfecting it4 ,the animal life is nobler than the organic1 whence the organic is subservient to the animal2 but there is not only no opposition1 hostility1 or antagonism between them1 but the strictest possible connexion1 dependence1 and subservience4 ,the sympathetic principle is nobler than the selfish1 whence the selfish is subservient to the sympathetic2 but there is not only no opposition1 hostility1 or antagonism between them1 but the strictest possible connexion1 dependence1 and subservience4 ,whatever is conducive to the perfection of the organic1 is equally conducive to the perfection of the animal life2 and whatever is conducive to the attainment of the true end of the selfish is equally conducive to the attainment of the true end of the sympathetic principle4 ,the perfection of the animal life cannot be promoted at the expense of the organic1 nor that of the organic at the expense of the animal2 neither can the ultimate end of the selfish principle be secured by the sacrifice of the sympathetic1 nor that of the sympathetic by the sacrifice of the selfish4 ,any attempt to exalt the animal life beyond what is compatible with the healthy state of the organic1 instead of accomplishing that end1 only produces bodily disease4 ,any attempt to extend the selfish principle beyond what is compatible with the perfection of the sympathetic1 or the sympathetic beyond what is compatible with the perfection of the selfish1 instead of accomplishing the end in view1 only produces mental disease4 ,opposing and jarring actions1 antagonizing and mutually destructive powers1 are combined in no other work of nature2 and it would be wonderful indeed were the only instance of it found in man1 the noblest of her works1 and in the mind of man1 the noblest part of her noblest work4 ,no one supposes that there is any such inharmonious combination in the organization of his physical frame1 and the notion that it exists in his mental constitution1 as it is founded in the grossest ignorance1 so it is productive of incalculable mischief4 ,in both1 indeed1 are manifest two great powers1 each distinct2 each having its own peculiar operation2 and the one being subservient to the other1 but both conducing alike to one common end4 ,by the addition of the apparatus of the animal to that of the organic life1 a nobler structure is built up than could have been framed by the organic alone3 by the addition of the sympathetic to the selfish part of the mental constitution1 a happier being is formed than could have been produced by the selfish alone4 ,and as the organic might have existed without the animal life1 but by the addition of the animal a new and superior being is formed1 so might the selfish part of the mental constitution1 and the pleasures that flow from it1 have existed alone2 but by the addition of the sympathetic1 a sum is added to enjoyment1 of the amount of which some conception may be formed by considering what human life would be1 with every selfish appetite and faculty gratified in the fullest conceivable degree1 but without any admixture whatever of sympathetic or social pleasure4 ,selfish enjoyment is not common4 ,if any one set himself to examine what at first view might seem a purely selfish pleasure1 he will soon be sensible that1 of the elements composing any given state of mind to which he would be willing to affix the term pleasurable1 a vast preponderance consists of sympathetic associations4 ,the more accurately he examine1 and the farther he carry his analysis1 the stronger will become his conviction1 that a purely selfish enjoyment1 that is1 a truly pleasurable state of mind1 in no degree1 mediately or immediately1 connected with the pleasurable state of another mind1 is exceedingly rare4 ,but if the constitution of human nature and the structure of human society alike render it difficult for the human heart to be affected with a pleasure in no degree derived from--absolutely and totally unconnected with sympathetic association1 of that complex pleasure which arises out of social intercourse1 partly selfish and partly sympathetic1 how far sweeter the sympathetic than the selfish part2 and as the sympathetic preponderates over the selfish1 how vast the increase of the pleasure6 ,and when matured1 exalted into affection--affection1 that holy emotion which exerts a transforming influence over the selfish part of human nature1 turning it into the sympathetic2 affection1 which renders the happiness of the beloved object inexpressibly dearer to the heart than its own2 affection1 among the benignant feelings of which as there is none sweeter so there is none stronger than that of self-devotion1 nay1 sometimes even of self-sacrifice2 affection1 which is sympathy pure1 concentrated1 intense--,oh how beautiful is the constitution of this part of our nature1 by which the most transporting pleasures the heart receives are the direct reflection of those it gives6 ,nor ought it to be overlooked1 that1 while nearly all the selfish1 like all the sensual pleasures1 cannot be increased beyond a fixed limit1 cannot be protracted beyond a given time1 are short-lived in proportion as they are intense1 and satiate the appetite they gratify1 the sympathetic pleasures are capable of indefinite augmentation2 are absolutely inexhaustible2 no limit can be set to their number1 and no bound to their growth2 they excite the appetite they gratify2 they multiply with and by participation1 and the more is taken from the fountain from which they flow1 the deeper1 the broader1 and the fuller the fountain itself becomes4 ,but not only is the mental state of affection in all its forms and degrees highly pleasurable1 but the very consciousness of being the object of affection is another pleasure perfectly distinct from that arising immediately from the affection itself4 ,it has been said of charity1 that it is twice blessed1 that it blesses alike him that gives and him that receives2 but love has in it a threefold blessing3 first1 in the mental state itself2 secondly1 in the like mental state which the manifestation of it produces in another2 and thirdly1 in the mental state inseparable from the consciousness of being the object of affection4 ,and this reflex happiness1 this happiness arising from the consciousness of being the object1 is even sweeter than any connected with being the subject of affection4 ,in like manner there is pleasure in the performance of beneficent actions2 in energetic1 constant1 and therefore ultimately successful exertions to advance the great interests of human kind1 in art1 in science1 in philosophy1 in education1 in morals1 in legislation1 in government2 whether those exertions are put forth in the study1 the school1 the senate1 or any less observed though perhaps not less arduous nor less important field of labour4 ,exertions of this kind beget in those for whom1 towards those by whom1 they are made1 benignant feelings--respect1 veneration1 gratitude1 love4 ,with such feelings the philosopher1 the instructor1 the legislator1 the statesman1 the philanthropist1 knows that he is1 or that1 sooner or later1 he will be regarded by his fellow men2 and in this consciousness there is happiness3 but this is another source of happiness perfectly distinct from that arising from the performance of beneficent actions2 it is a new happiness superadded to the former1 and1 if possible1 still more exquisite4 ,thus manifold is the beneficent operation of the sympathetic affection3 thus admirable is the provision made in the constitution of our nature for the excitement and extension of this affection1 and1 through its instrumentality1 for the multiplication and exaltation of enjoyment6 ,in affections and actions of the class just referred to1 and in the pleasures that result from them1 there is much of the nature which is commonly termed moral4 ,and the power to which the moral affections and actions are referred is usually and justly considered as the supreme faculty of the mind2 for it is the regulator and guide of all the others2 it is that by which they attain their proper and ultimate object4 ,of whatever pleasure human nature is capable in sensation1 in idea1 in appetite1 in passion1 in emotion1 in affection1 in action2 whatever is productive of real pleasure1 in contradistinction to what only cheats with the false hope of pleasure2 whatever is productive of pure pleasure1 in contradistinction to what is productive partly of pleasure and partly of pain1 and consequently productive not of pure1 but of mixed pleasure2 whatever is productive of a great degree of pleasure in contradistinction to what is productive of a small degree of pleasure2 whatever is productive of lasting pleasure1 in contradistinction to what is productive of temporary pleasure2 whatever is productive of ultimate pleasure1 in contradistinction to what is productive of immediate pleasure1 but ultimate pain2 this greatest and most perfect pleasure it is the part of the moral faculty to discover4 ,in the degree in which the operation of this faculty is correct and complete1 it enables the human being to derive from every faculty of his nature the greatest1 the purest1 the most enduring pleasure2 that is1 the maximum of felicity4 ,this is the proper scope and aim of the moral faculty2 to this its right exercise is uniformly conducive2 and this1 as it is better cultivated and directed1 it will accomplish in a higher degree1 in a continual progression1 to which no limit can be assigned4 ,but if the operation of this faculty be to render every other in the highest degree conducive to happiness1 conformity to the course of conduct required by it1 must of course be that highest happiness4 ,conformity to the course of conduct pointed out by the moral faculty as conducive in the highest degree to happiness is moral excellence1 or1 in the definite and exact sense of the word1 virtue4 ,and in this sense it is that virtue is happiness4 ,it is because it discriminates the true sources of happiness1 that is1 directs every other faculty into its proper course1 and guides it in that course to the attainment of its ultimate object1 that the moral faculty is ranked as the highest faculty of the mind4 ,supposing the operation of this faculty to be perfect1 it is but an identical expression to say1 that to follow its guidance implicitly is to follow the road that leads to the most perfect happiness4 ,but1 over and above the happiness thus directly and necessarily resulting from yielding uniform and implicit obedience to the moral faculty1 there is1 in the very consciousness of such conformity1 a new happiness1 as pure as it is exalted4 ,thus1 in a twofold manner1 is the moral the highest faculty of the mind1 the source of its highest happiness2 and thus manifest it is1 from every view that can be taken of the constitution of human nature1 that every faculty with which it is endowed1 from the highest to the lowest1 not only affords its own proper and peculiar pleasure1 but that each1 as it successively rises in the scale1 is proportionately the source of a nobler kind1 and a larger amount of enjoyment4 ,and the pleasure afforded by the various faculties with which the human being is endowed is the immediate and direct result of their exercise4 ,with the exception of the organic organs1 and the reason for the exception in regard to them has been assigned1 the action of the organs is directly pleasurable4 ,from the exercise of the organs of sense1 from the operation of the intellectual faculties1 from appetite1 passion1 and affection1 pleasure flows as directly as the object for which the instrument is expressly framed4 ,and pleasure is the ordinary result of the action of the organs2 pain is sometimes the result1 but it is the extraordinary not the ordinary result4 ,whatever may be the degree of pain occasionally produced1 or however protracted its duration1 yet it is never the natural1 that is1 the usual or permanent state1 either of a single organ1 or of an apparatus1 or of the system4 ,the usual1 the permanent1 the natural condition of each organ1 and of the entire system1 is pleasurable4 ,abstracting1 therefore1 from the aggregate amount of pleasure1 the aggregate amount of pain1 the balance in favour of pleasure is immense4 ,this is true of the ordinary experience of ordinary men1 even taking their physical and mental states such as they are at present2 but the ordinary physical and mental states1 considered as sources of pleasure of every human being1 might be prodigiously improved2 and some attempt will be made1 in a subsequent part of this work1 to show in what manner and to what extent4 ,it has been already stated that there are cases in which pleasure is manifestly given for its own sake2 in which it is rested in as an ultimate object3 but the converse is never found3 in no case is the excitement of pain gratuitous4 ,among all the examples of secretion1 there is no instance of a fluid1 the object of which is to irritate and inflame3 among all the actions of the economy1 there is none1 the object of which is the production of pain4 ,moreover1 all such action of the organs1 as is productive of pleasure1 is conducive to their complete development1 and consequently to the increase of their capacity for producing pleasure2 while all such action of the organs as is productive of pain is preventive of their complete development1 and consequently diminishes their capacity for producing pain4 ,the natural tendency of pleasure is to its own augmentation and perpetuity4 ,pain1 on the contrary1 is self-destructive4 ,special provision is made in the economy1 for preventing pain from passing beyond a certain limit1 and from enduring beyond a certain time4 ,pain1 when it reaches a certain intensity1 deadens the sensibility of the sentient nerve2 and when it lasts beyond a certain time1 it excites new actions in the organ affected1 by which the organ is either restored to a sound state1 or so changed in structure that its function is wholly abolished4 ,but change of structure and abolition of function1 if extensive and permanent1 are incompatible with the continuance of life4 ,if1 then1 the actions of the economy1 excited by pain1 fail to put an end to suffering by restoring the diseased organ to a healthy state1 they succeed in putting an end to it by terminating life4 ,pain1 therefore1 cannot be so severe and lasting as materially to preponderate over pleasure1 without soon proving destructive to life4 ,but the very reverse is the case with pleasure4 ,all such action of the organs as is productive of pleasure is conducive to the perpetuation of life4 ,there is a close connexion between happiness and longevity4 ,enjoyment is not only the end of life1 but it is the only condition of life which is compatible with a protracted term of existence4 ,the happier a human being is1 the longer he lives2 the more he suffers1 the sooner he dies2 to add to enjoyment1 is to lengthen life2 to inflict pain1 is to shorten the duration of existence4 ,as there is a point of wretchedness beyond which life is not desirable1 so there is a point beyond which it is not maintainable4 ,the man who has reached an advanced age cannot have been1 upon the whole1 an unhappy being2 for the infirmity and suffering which embitter life cut it short4 ,every document by which the rate of mortality among large numbers of human beings can be correctly ascertained contains in it irresistible evidence of this truth4 ,in every country1 the average duration of life1 whether for the whole people or for particular classes1 is invariably in the direct ratio of their means of felicity2 while1 on the other hand1 the number of years which large portions of the population survive beyond the adult age may be taken as a certain test of the happiness of the community4 ,how clear must have been the perception of this in the mind of the ,jewish legislator when he made the promise1 ,,that ,,thy ,,days ,,may ,,be ,,long ,,in ,,the ,,land ,,which ,,the ,,lord ,,thy ,,god ,,hath ,,given ,,thee--the sanction of every religious observance1 and the motive to every moral duty6 ,deeply then are laid the fountains of happiness in the constitution of human nature4 ,they spring from the depths of man's physical organization2 and from the wider range of his mental constitution they flow in streams magnificent and glorious4 ,it is conceivable that from the first to the last moment of his existence1 every human being might drink of them to the full extent of his capacity4 ,why does he not8 ,the answer will be found in that to the following question4 ,what must happen before this be possible8 ,the attainment of clear and just conceptions on subjects1 in relation to which the knowledge hitherto acquired by the most enlightened men is imperfect4 ,physical nature1 every department of it1 at least1 which is capable of influencing human existence and human sensation2 human nature1 both the physical and the mental part of it2 institutions so adapted to that nature as to be capable of securing to every individual1 and to the whole community1 the maximum of happiness with the minimum of suffering--this must be known4 ,but knowledge of this kind is of slow growth4 ,to expect the possession of it on the part of any man in such a stage of civilization as the present1 is to suppose a phenomenon to which there is nothing analogous in the history of the human mind4 ,the human mind is equally incapable of making a violent discovery in any department of knowledge1 and of taking a violent bound in any path of improvement4 ,what we call discoveries and improvements are clear1 decided1 but for the most part gentle1 steps in advancement of the actual and immediately-preceding state of knowledge4 ,the human mind unravels the great chain of knowledge1 link by link2 when it is no longer able to trace the connecting link1 it is at a stand2 the discoverer1 in common with his contemporaries1 seeing the last ascertained link1 and from that led on by analogies which are not perceived by1 or which do not impress1 others1 at length descries the next in succession2 this brings into view new analogies1 and so prepares the way for the discernment of another link2 this again elicits other analogies which lead to the detection of other links1 and so the chain is lengthened4 ,and no link1 once made out1 is lost4 ,chemists tell us that the adjustment of the component elements of water is such1 that although they readily admit of separation and are subservient to their most important uses in the economy of nature by this very facility of decomposition1 yet that their tendency to recombination is equal1 so that the quantity of water actually existing at this present moment in the globe is just the same as on the first day of the creation1 neither the operations of nature1 nor the purposes to which it has been applied by man1 having used up1 in the sense of destroying1 a single particle of it4 ,alike indestructible are the separate truths that make up the great mass of human knowledge4 ,in their ready divisibility and their manifold applications1 some of them may sometimes seem to be lost2 but if they disappear1 it is only to enter into new combinations1 many of which themselves become new truths1 and so ultimately extend the boundaries of knowledge4 ,whatever may have been the case in time past1 when the loss of an important truth1 satisfactorily and practically established1 may be supposed possible1 such an event is inconceivable now when the art of printing at once multiplies a thousand records of it1 and1 with astonishing rapidity1 makes it part and parcel of hundreds of thousands of minds4 ,a thought more full of encouragement to those who labour for the improvement of their fellow beings there cannot be4 ,no onward step is lost2 no onward step is final2 every such step facilitates and secures another4 ,the savage state1 that state in which gross selfishness seeks its object simply and directly by violence1 is past4 ,the semi-savage or barbarous state1 in which the grossness of the selfishness is somewhat abated1 and the violence by which it seeks its object in some degree mitigated1 by the higher faculties and the gentler affections of our nature1 but in which war still predominates1 is also past4 ,to this has succeeded the state in which we are at present1 the so-called civilized state--a state in which the selfish principle still predominates1 in which the justifiableness of seeking the accomplishment of selfish purposes by means of violence1 that of war among the rest1 is still recognized1 but in which violence is not the ordinary instrument employed by selfishness1 its ends being commonly accomplished by the more silent1 steady1 and permanent operation of institutions4 ,this state1 like the preceding1 will pass away4 ,how soon1 in what precise mode1 by what immediate agency1 none can tell4 ,but we are already in possession of the principle which will destroy the present and introduce a better social condition1 namely1 the principle at the basis of the social union1 ,,the ,,maximum ,,of ,,the ,,aggregate ,,of ,,happiness2 ,,the ,,maximum ,,of ,,the ,,aggregate ,,of ,,happiness ,,sought ,,by ,,the ,,promotion ,,of ,,the ,,maximum ,,of ,,individual ,,happiness6 ,,chapter ,,iv4 ,relation between the physical condition and happiness1 and between happiness and longevity--,longevity a good1 and why--,epochs of life--,the age of maturity the only one that admits of extension--,proof of this from physiology--,proof from statistics--,explanation of terms--,life a fluctuating quantity--,amount of it possessed in ancient ,rome3 in modern ,europe3 at present in ,england among the mass of the people and among the higher classes4 ,life depends on the action of the organic organs4 ,the action of the organic organs depends on certain physical agents4 ,as each organic organ is duly supplied with the physical agent by which it carries on its respective process1 and as it duly appropriates what it receives1 the perfection of the physical condition is attained2 and1 according to the perfection or imperfection of the physical condition1 supposing no accident interrupt its regular course1 is the length or the brevity of life4 ,it is conceivable that the physical condition might be brought to a high degree of perfection1 the mind remaining in a state but little fitted for enjoyment2 because it is necessary to enjoyment that there be a certain development1 occupation1 and direction of the mental powers and affections3 and the mental state may be neglected1 while attention is paid to the physical processes4 ,but the converse is not possible4 ,the mental energies cannot be fully called forth while the physical condition is neglected4 ,happiness presupposes a certain degree of excellence in the physical condition2 and unless the physical condition be brought to a high degree of excellence1 there can be no such development1 occupation1 and direction of the mental powers and affections as is requisite to a high degree of enjoyment4 ,that state of the system in which the physical condition is sound is in itself conducive to enjoyment2 while a permanent state of enjoyment is in its turn conducive to the soundness of the physical condition4 ,it is impossible to maintain the physical processes in a natural and vigorous condition if the mind be in a state of suffering4 ,the bills of mortality contain no column exhibiting the number of persons who perish annually from bodily disease1 produced by mental suffering2 but every one must occasionally have seen appalling examples of the fact4 ,every one must have observed the altered appearance of persons who have sustained calamity4 ,a misfortune1 that struck to the heart1 happened to a person a year ago2 observe him some time afterwards2 he is wasted1 worn1 the miserable shadow of himself2 inquire about him at the distance of a few months1 he is no more4 ,it is stated by ,m4 ,villerm1 that the ordinary rate of mortality in the prisons of ,france1 taking all together1 is one in twenty-three--a rate which corresponds to the age of sixty-five in the common course of life4 ,but in the vast majority of cases the unfortunate victims of the law are no older than from twenty-five to forty-five years of age4 ,taking them at the mean age of thirty-five1 it follows that the suffering from imprisonment1 and from the causes that lead to it1 is equivalent to thirty years wear and tear of life4 ,but this is not all2 for it is found that1 during imprisonment1 the ordinary chances of death are exactly quadrupled4 ,in regard to the whole population of a country1 indigence may be assumed to be a fair measure of unhappiness1 and wealth of happiness4 ,if the rate of mortality in the indigent class be compared with that of the wealthy1 according to ,m4 ,villerm1 it will be found in some cases to be just double4 ,thus it is affirmed that1 in some cases in ,france1 taking equal numbers1 where there are one hundred deaths in a poor arrondissement1 there are only fifty in a rich2 and that taking together the whole of the ,french population1 human life is protracted twelve years and a half among the wealthy beyond its duration among the poor3 consequently1 in the one class1 a child1 newly born1 has a probability of living forty-two and a half years2 in the other only thirty years4 ,in the great life-insurance establishments in ,england1 a vast proportion of the persons who insure their lives are persons compelled to do so by their creditors2 while three-fourths of those who voluntarily insure their lives are professional men1 living in great towns1 and experiencing the anxieties and fatigues1 the hopes and disappointments of professional life4 ,in one of these establishments in ,london1 out of #ccj deaths that happened in twenty-six years preceding the year #ahca1 it was found that eleven died by suicide1 being one in thirty1 implying the existence of an appalling amount of mental suffering4 ,the number of persons belonging to an insurance office who perish by suicide is sure to be accurately known1 death by suicide rendering the policy void4 ,it would be most erroneous to suppose that these persons put an end to their existence under the mere influence of the mental states of disappointment and despondency4 ,the mind reacted upon the body3 produced physical disease1 probably inflammation of the brain1 and under the excitement of this physical disease1 the acts of suicide were committed4 ,more than one case has come to my knowledge in which inflammation of the brain having been excited by mental suffering1 suicide was committed by cutting the throat4 ,during the flow of blood1 which was gradual1 the brain was relieved2 the mind became perfectly rational2 and the patient might have been saved had a surgeon been upon the spot1 or had the persons about the patient known where and how to apply the pressure of the finger to staunch the flow of blood1 until surgical aid could be procured4 ,by a certain amount and intensity of misery life may be suddenly destroyed2 by a smaller amount and intensity1 it may be slowly worn out and exhausted4 ,the state of the mind affects the physical condition2 but the continuance of life is wholly dependent on the physical condition3 it follows that in the degree in which the state of the mind is capable of affecting the physical condition1 it is capable of influencing the duration of life4 ,were the physical condition always perfect1 and the mental state always that of enjoyment1 the duration of life would always be extended to the utmost limit compatible with that of the organization of the body4 ,but as this fortunate concurrence seldom or never happens1 human life seldom or never numbers the full measure of its days4 ,uniform experience shows1 however1 that1 provided no accident occur to interrupt the usual course1 in proportion as body and mind approximate to this state1 life is long2 and as they recede from it1 it is short4 ,improvement of the physical condition affords a foundation for the improvement of the mental state2 improvement of the mental state improves up to a certain point the physical condition2 and in the ratio in which this twofold improvement is effected1 the duration of life increases4 ,longevity then is a good1 in the first place1 because it is a sign and a consequence of the possession of a certain amount of enjoyment2 and in the second place1 because this being the case1 of course in proportion as the term of life is extended1 the sum of enjoyment must be augmented4 ,and this view of longevity assigns the cause1 and shows the reasonableness of that desire for long life which is so universal and constant as to be commonly considered instinctive4 ,longevity and happiness1 if not invariably1 are generally1 co-incident4 ,if there may be happiness without longevity1 the converse is not possible3 there cannot be longevity without happiness4 ,unless the state of the body be that of tolerable health1 and the state of the mind that of tolerable enjoyment1 long life is unattainable3 these physical and mental conditions no longer existing1 nor capable of existing1 the desire of life and the power of retaining it cease together4 ,an advanced term of life and decrepitude are commonly conceived to be synonymous3 the extension of life is vulgarly supposed to be the protraction of the period of infirmity and suffering1 that period which is characterized by a progressive diminution of the power of sensation1 and a consequent and proportionate loss of the power of enjoyment1 the sans teeth1 sans eyes1 sans taste1 sans every thing4 ,but this is so far from being true1 that it is not within the compass of human power to protract in any sensible degree the period of old age properly so called1 that is1 the stage of decrepitude4 ,in this stage of existence1 the physical changes that successively take place clog1 day by day1 the vital machinery1 until it can no longer play4 ,in a space of time1 fixed within narrow limits1 the flame of life must then inevitably expire1 for the processes that feed it fail4 ,but though1 when fully come1 the term of old age cannot be extended1 the coming of the term may be postponed4 ,to the preceding stage1 an indefinite number of years may be added4 ,and this is a fact of the deepest interest to human nature4 ,the division of human life into periods or epochs is not an arbitrary distinction1 but is founded on constitutional differences in the system1 dependent on different physiological conditions4 ,the periods of infancy1 childhood1 boyhood1 adolescence1 manhood1 and old age1 are distinguished from each other by external characters1 which are but the outward signs of internal states4 ,in physiological condition1 the infant differs from the child1 the child from the boy1 the boy from the man1 and the adult from the old man1 as much in physical strength as in mental power4 ,there is an appointed order in which these several states succeed each other2 there is a fixed time at which one passes into another4 ,that order cannot be inverted3 no considerable anticipation or postponement of that fixed time can be effected4 ,in all places and under all circumstances1 at a given time1 though not precisely at the same time in all climates and under all modes of life1 infancy passes into childhood1 childhood into boyhood1 boyhood into adolescence1 and adolescence into manhood4 ,in the space of two years from its birth1 every infant has ceased to be an infant1 and has become a child2 in the space of six years from this period1 every male child will have become a boy2 add eight years to this time1 and every boy will have become a young man2 in eight years more1 every young man will have become an adult man2 and in the subsequent ten years1 every adult man will have acquired his highest state of physical perfection4 ,but at what period will this state of physical perfection decline8 ,what is the maximum time during which it can retain its full vigour8 ,is that maximum fixed8 ,is there a certain number of years in which1 by an inevitable law1 every adult man necessarily becomes an old man8 ,is precisely the same number of years appointed for this transition to every human being8 ,can no care add to that number8 ,can no imprudence take from it8 ,does the physiological condition or the constitutional age of any two individuals ever advance to precisely the same point in precisely the same number of years8 ,physically and mentally1 are not some persons older at fifty than others are at seventy8 ,and do not instances occasionally occur in which an old man1 who reaches even his hundredth year1 retains as great a degree of juvenility as the majority of those who attain to eighty8 ,if this be so1 what follows8 ,one of the most interesting consequences that can be presented to the human mind4 ,the duration of the periods of infancy1 childhood1 boyhood1 and adolescence1 is fixed by a determinate number of years4 ,nothing can stay1 nothing retard1 the succession of each4 ,alike incapable of any material protraction is the period of old age4 ,it follows that every year by which the term of human existence is extended is really added to the period of mature age2 the period when the organs of the body have attained their full growth and put forth their full strength2 when the physical organization has acquired its utmost perfection2 when the senses1 the feelings1 the emotions1 the passions1 the affections1 are in the highest degree acute1 intense1 and varied2 when the intellectual faculties1 completely unfolded and developed1 carry on their operations with the greatest vigour1 soundness1 and continuity2 in a word1 when the individual is capable of receiving and of communicating the largest amount of the highest kind of enjoyment4 ,a consideration more full of encouragement1 more animating1 there cannot be4 ,the extension of human life1 in whatever mode and degree it may be possible to extend it1 is the protraction of that portion of it1 and only of that portion of it1 in which the human being is capable of ,,receiving ,,and ,,of ,,communicating ,,the ,,largest ,,measure ,,of ,,the ,,noblest ,,kind ,,of ,,enjoyment4 ,considerations1 purely physiological1 establish this indubitably2 but it is curious that a class of facts1 totally different from those of a physiological nature1 equally prove it2 namely1 the results obtained from the observation of the actual numbers that die at different ages1 and the knowledge consequently acquired of the progressive decrement of life4 ,mortality is subject to a law1 the operation of which is as regular as that of gravitation4 ,the labours of my valued friend ,mr4 ,finlaison1 the actuary of the ,national ,debt1 have not only determined what that law is in relation to different nations at different periods of their history1 but this celebrated calculator has also invented a striking mode of expressing and representing the fact4 ,he constructed a chart on which #ajj perpendicular lines1 answering to the respective ages of human life1 are laid down and numbered in succession4 ,these are crossed at right angles by #ejj horizontal lines2 so that1 in the manner of musical notation1 a point may be laid down either on the horizontal line1 or on the space between any two of them3 and thus1 #ajjj points may be laid down on each of the perpendicular lines4 ,the horizontal lines are in like manner numbered from #a to #ajjj1 ascending from the base4 ,taking any observation which shows the number of living persons that commence1 and in like manner the number that die in each particular year of human life1 the calculator reduced by the rule of three every such actual number of living persons for every separate year to #aj1jjj3 he next showed the corresponding proportion of deaths out of such #aj1jjj4 ,these proportions he represented on the chart by a point inserted on the horizontal line or space for the number of deaths1 and on the perpendicular line for the particular age4 ,he then connected all the points so laid down1 and the result is a curve1 representing the track of death through an equal number of human beings existing at each age of life4 ,as the curve rises on the perpendicular line1 at any given age1 it indicates by so much an increase of the mortality at that age2 and as the curve falls1 the reverse is denoted4 ,now1 it is a highly interesting fact1 that the curves on this chart drawn upon it before the physiological phenomena were known to the operator1 placed there because such he found to be the actual path along which death marshals his course1 exactly correspond to the epochs which physiology teaches to be determinate stages of human existence4 ,the infant1 the child1 the boy1 the adolescent1 the man1 the old man1 are not exposed to the same danger4 ,the liability of each to death is not merely different2 it is widely different2 the liability of each class is uniformly the same1 the circumstances influencing life remaining the same2 and under no known change of circumstances does the relative liability of the class vary2 under no change does the liability of the adolescent become that of the infant1 or the liability of the adult that of the aged4 ,take from any statistical document any number of persons2 observe out of this number the proportion that dies at the different stages just enumerated2 and the period of human life which admits of extension will be strikingly manifest4 ,take with this view the ,prussian statistical tables1 the general correctness of which is admitted4 ,from these tables it appears1 and the correctness of the result is confirmed by a multitude of other tables1 that out of a million living male births1 there will die in the first year of life #ahj1dib infants1 and out of the like number of living female births1 there will die #aed1gje infants4 ,let us follow up the decrement of life through the different epochs of human existence1 confining our observations to the male sex1 in which the development is more emphatically marked4 ,in ,mr4 ,finlaison's report1 printed by the ,house of ,commons on the #cjth of ,march1 #ahbi1 there are six original observations on the mortality of as many separate sets of annuitants of the male sex4 ,from an examination and comparison of these observations1 it appears--#ast4 ,that the rate of mortality falls to a minimum at the close of the period of childhood4 #b;d4 ,that from this point the mortality rises until the termination of adolescence or the commencement of adult age4 #c;d4 ,that from the commencement of adult age the mortality again declines1 and continues to decline to the period of perfect maturity4 ,and #dth4 ,that from the period of perfect maturity1 the mortality rises1 and uniformly1 without a single exception1 returns1 at the age of forty-eight1 to the point at which it stood at the termination of adolescence4 ,these results clearly indicate that certain fixed periods are marked by nature as epochs of human life2 and that at the date of the recorded facts which furnish the data for these observations1 and as far as regards the class of persons to which they relate1 the age of forty-eight was the exact point at which the meridian of life was just passed1 and a new epoch began4 ,the following table exhibits at one view the exact results of each of the observations4 ,for example1 ,according to ,the mortality ,from whence ,from this ,and from this the is at a it rises point it age it again observation1 minimum at the until declines rises1 but is not ,no4 age of the age of to the equal to the age of mortality in the #b;d column until the age of #ae -- #ac -- #bc -- #cd -- #dh #af -- #ac -- #bc -- #ce -- #dh #ag -- #ad -- #bb -- #cc -- #dh #ah -- #ac -- #bc -- #cc -- #dh #ai -- #ac -- #bd -- #cd -- #dh #bj -- #ac -- #bd -- #cd -- #dh ,the observation1 ,no4 #ae1 is founded on the large mass of #i1cdg lives and #d1hgj deaths4 ,from this observation1 it appears that1 at the age of thirteen1 the mortality out of a million is #e1gdb1 being #agd1gej less than in the first year of infancy ,at the age of twenty-three1 it is #ae1jgd1 being #i1ccb more than at the close of childhood4 ,at the age of thirty-four1 the period of complete manhood1 it falls to #aa1gjg1 being #c1cfg less than at the close of adolescence4 ,at the age of forty-eight1 the mortality returns to #ad1hgj1 all but identically the same as at twenty-three1 the adult age4 ,from the age of forty-eight1 when1 as has been stated1 life just begins to decline from its meridian1 the mortality advances slowly1 but in a steady and regular progression4 ,thus1 at the age of fifty-eight it is #bi1ahe1 being #ad1cae more than at the preceding decade1 or almost exactly double4 ,at the age of sixty-eight1 it is #fa1gda1 being #cb1eef more than at the preceding decade1 or more than double4 ,at the age of seventy-eight1 it is #aad1bee1 being #eb1ead more than at the preceding decade4 ,at the age of eighty-eight1 it is #bdf1hjc1 being #acb1edh more than at the preceding decade4 ,during the first year of infancy1 as has been shown1 the mortality out of a million is #ahj1dib4 ,at the extreme age of eighty-four1 it is #agh1acj1 very nearly the same as in the first year of infancy4 ,greatly as the mortality of all the other epochs of life is affected by country1 by station1 by a multitude of influences arising out of these and similar circumstances2 yet the concurrent evidence of all observation shows that at this and the like advanced ages the mean term of existence is nearly the same in all countries1 at all periods1 and among all classes of society4 ,thus1 among the nobility and gentry of ,england1 the expectation of life at eighty-four is four years2 among the poor fishermen of ,ostend1 it is precisely the same4 ,m4 ,de ,parcieux1 who wrote just ninety years ago1 establishes the expectation of life at that time in ,france1 at the same age1 to have been three and a half years2 and ,halley1 who wrote #abj years ago1 and whose observations are derived from documents which go back to the end of the seventeenth century1 states the expectation of life at eighty-four to be two years and nine months4 ,from these statements1 then1 it is obvious1 that from the termination of infancy at three years of age1 a decade of years brings childhood to a close1 during which the mortality1 steadily decreasing1 comes to its minimum4 ,another decade terminates the period of adolescence1 during which the mortality as steadily advances4 ,a third decade changes the young adult into a perfect man1 and during this period1 the golden decade of human life1 the mortality again diminishes2 while1 during another decade and a half1 the mortality slowly rises1 and returns at the close of the period to the precise point at which it stood at adult age4 ,thus the interval between the period of birth and that of adult age includes a term of twenty-three years4 ,the interval between the period of adult age and that when life just begins to decline from its meridian1 includes a term of twenty-four years3 consequently1 a period more than equal to all the other epochs of life from birth to adult age is enjoyed1 during which mortality makes no advance whatever4 ,now the term of years included in the several epochs that intervene between birth and adult age is rigidly fixed4 ,thus the period of infancy includes precisely three years1 that of childhood ten years1 and that of adolescence ten years4 ,within the space of time comprehended in these intervals1 physiological changes take place1 on which depend every thing that is peculiar to the epochs4 ,these changes cannot be anticipated1 cannot be retarded1 except in a very slight degree4 ,in all countries1 among all classes1 they take place in the same order and nearly in the same space of time4 ,in like manner1 in extreme old age1 or the age of decrepitude1 which may be safely assumed to commence at the period when the mortality equals that of the first year of infancy1 namely1 the age of eighty-four1 physiological changes take place1 which1 within a given space of time1 inevitably bring life to a close4 ,that space of time1 in all countries1 in all ranks1 in all ages1 or rather as far back as any records enable us to trace the facts1 appears to be the same4 ,as within a given time the boy must ripen into manhood1 so within a given time the man of extreme old age must be the victim of death4 ,consequently1 it is the interval between the adult age and the age of decrepitude1 and only this1 that is capable of extension4 ,during the interval between adult age and the perfect meridian of life1 comprehending at present1 as we have seen1 a period of twenty-four years1 the constitution remains stationary1 mortality making no sensible inroad upon it4 ,but there is no known reason why this stationary or mature period of life should1 like the determinate epochs1 be limited to a fixed term of years4 ,on the contrary1 we do in fact know that it is not fixed2 for we know that the physiological changes on which age depends are1 in some cases1 greatly anticipated1 and in others1 proportionately postponed2 so that some persons are younger at sixty1 and even at seventy1 than others are at fifty2 whereas1 an analogous anticipation or postponement of the other epochs of life is never witnessed4 ,so complete is the proof1 that the extension of human life can consist in the protraction neither of the period of juvenility1 nor in that of senility1 but only in that of maturity4 ,were it necessary to adduce further evidence of this most interesting fact1 it would be found equally in the statistics of disease as in those of mortality4 ,indeed1 the evidence derived from both these sources must be analogous1 because mortality is invariably proportionate to the causes of mortality1 of which causes1 sickness1 in all its forms1 may be taken as the general or collective expression4 ,we do not possess the same means of illustrating the prevalence of disease through all the epochs of life as we do of showing the intensity of mortality2 yet the report of ,mr4 ,finlaison1 already referred to1 enables us to show its comparative prevalence at several of those stages4 ,thus1 from this document1 it appears1 that among the industrious poor of ,london1 members of benefit societies1 out of a million of males1 the proportion constantly sick at the age of twenty-three1 is #ai1daj2 at the age of twenty-eight1 it is #ai1fgj2 at the age of thirty-three1 it is #ai1djj2 at the age of thirty-eight1 it is #bc1hgj2 at the age of forty-three1 it is #bf1bfj2 at the age of forty-eight1 it is #bf1adj2 at the age of fifty-three1 it is #bg1jfj2 at the age of fifty-eight1 it is #cf1ihj2 at the age of sixty-three1 it is #eg1jjj2 at the age of sixty-eight1 it is #ajh1jdj2 at the age of seventy-three and upwards1 it is #cag1bcj4 ,the prevalence of sickness is not an exact and invariable measure of the intensity of mortality2 but there is a close connexion between them1 as is manifest from the progressively increasing amount of sickness1 as age advances4 ,thus1 in the first ten years from the age of twenty-three to that of thirty-three1 there is no increase of sickness1 its prevalence is all but identically the same2 in the next ten years from the age of thirty-three to that of forty-three1 the increase of sickness1 as compared with that of the preceding decade1 is #f1hfj2 in the next ten years from the age of forty-three to that of fifty-three1 the increase is only #hjj2 in the next ten years from the age of fifty-three to that of sixty-three1 the increase is #bi1idj1 while from the age of sixty-three to seventy-three1 it is #bfj1bcj4 ,such are the results derived from the experience of disease considered in the aggregate1 all its varied forms taken together4 ,i am enabled further to present an exact and most instructive proof1 that one particular disease which1 in this point of view1 may be considered as more important than any other1 because it is the grand agent of death1 namely fever1 carries on its ravages in a ratio which steadily and uniformly increases as the age of its victim advances4 ,having submitted the experience of the ,london ,fever ,hospital for the ten years preceding ,january #ahcd1 an observation including nearly #f1jjj patients affected with this malady1 to ,mr4 ,finlaison1 it was subjected by him to calculation4 ,among other curious and instructive results to be stated hereafter1 it was found that the mortality of fever resolves itself into the following remarkable progression4 ,thus suppose #ajj1jjj patients to be attacked with this disease between the ages of #e and #af1 of these there would die - #h1bff and of an equal number between #ae and #bf there would die #aa1did #be and #cf #ag1jga #ce and #df #ba1ifj #de and #ef #cj1dic #ee and #ff #dj1gjh #fe and upwards #dd1fdc ,thus the risk of life from this malady is twice as great at the age of thirty-one as it is at eleven4 ,it is also nearly twice as great at forty-one as it is at twenty-one4 ,it is five times as great at sixty-one as it is at eleven1 and nearly four times as great above sixty-five as it is at twenty-one4 ,from the whole of the foregoing statements1 it is manifest that life is a fluctuating quantity4 ,in order to compare this fluctuating quantity under different circumstances1 writers on this branch of statistics use several terms1 the exact meaning of which it is desirable to explain4 ,it is1 for example1 very important to have a clear understanding of what is meant by such expressions as the following3 the expectation1 the probability1 the value1 the decrement of life1 and the law of mortality4 #a4 ,,the ,,expectation ,,of ,,life4 ,it is important to bear in mind that several expressions in common use have a signification perfectly synonymous with this3 namely1 share of existence2 mean duration of life2 la vie moyenne4 ,by these terms is expressed the total number of years1 including also the fractional parts of a year1 ordinarily attained by human beings from and after any given age4 ,suppose1 for example1 that one thousand persons enter on the eighty-sixth year of their age3 suppose the number of years and days which each one of them lives afterwards be observed and recorded2 suppose the number ultimately attained by each be formed into a sum total2 suppose this total be divided equally among the thousand1 the quotient of this division is said to be each one's share of existence1 or his mean duration of life1 or his expectation of life4 ,thus1 of the thousand persons in the present case supposed to commence the age of eighty-five1 suppose the number of years they collectively attain amount to #c1ejj years3 the one-thousandth part of #c1ejj is three and a half3 three years and a half then is said to be the expectation of life at the age of eighty-five1 because1 of all the persons originally starting1 this is the equal share of existence that falls to the lot of each4 #b4 ,,probability ,,of ,,life2 or the probable duration of life1 la vie probable4 ,these are synonymous terms1 in use chiefly among continental writers as an expression of the comparative duration of life4 ,the tabular methods of setting forth the duration of life consist1 for the most part1 in assuming that #aj1jjj infants are born2 and that at the age of one1 two1 three1 and each successive year of life1 there are so many still remaining in existence4 ,fix on any age2 observe what number remain alive to commence that age2 note at what age this number decreases to one-half2 the age at which they so come to one-half is called the probable term of life2 because1 say the continental writers1 it is an equal wager whether a person shall or shall not be alive at that period4 ,thus1 suppose one thousand males commence together the age of eighty-four2 suppose the table indicate that there will be alive at the age of eighty-five1 #hag2 at the age of eighty-six1 #fdh2 at the age of eighty-seven1 #dic2 at the age of eighty-eight1 #ceg1 and so on4 ,in the present case1 the probable duration of life at eighty-four is said to be very nearly three years1 because1 at the age of eighty-seven there are left alive #dic1 very nearly one-half of the thousand that originally started together4 #c4 ,,value ,,of ,,life4 ,this term1 when used accurately1 expresses the duration of life as measured by one or other of the methods already expounded4 ,but it is sometimes popularly used in a loose and singularly inaccurate sense4 ,thus it is very commonly said--,such a man's life is not worth ten years' purchase1 which is the same thing as to say1 that an annuity1 suppose a hundred pounds a year1 payable during the life of the person in question1 is not worth ten times its magnitude1 that is one thousand pounds4 ,if a thousand pounds be put into a bank at some rate of interest to be agreed upon1 and if a hundred pounds be drawn every year from the stock1 the expression under consideration affirms that the person in question will be dead before the principal and interest are exhausted4 ,for instance1 at four per cent41 the value of an annuity of one hundred pounds to a man of the age of twenty-five is #afidl41 which is #af-i_/aj years' purchase2 whereas1 his expectation of life at that age is #ce-i_/aj years4 #d4 ,,law ,,of ,,mortality4 ,by this term is expressed the proportion out of any determinate number of human beings who enter on a given year of age1 that will die in that year4 ,every observation on the duration of life presents certain numbers1 which1 by recorded facts1 are found to pass through each year of age1 and also shows how many have died or failed to pass through every year of age4 ,those numbers1 by the rule of three1 are converted into the proportions who would die at each age out of one million of persons1 if such a number had commenced it4 ,suppose1 then1 a million of persons to be in existence at the first year of age2 suppose a million to be in existence at the second year of age2 suppose a million to be in existence at the third year of age2 and in this manner suppose an equal number to be in existence at the commencement of each and every year to the extreme term of human life4 ,now1 the proportions that by actual observation are found to die at each and every year out of the million that were alive at the commencement of it1 form separately the law of mortality for each year1 and collectively for the whole of life4 #e4 ,,decrement ,,of ,,life4 ,assuming1 as before1 that a million of male children are born alive 7for the still-born must be excluded from the calculation7 if it be found that #ahj1dib would die in the first year1 it follows that the difference1 namely1 #hai1ejh1 will enter upon the age of one year4 ,suppose the law of mortality indicate that the proportion that will die1 out of a million1 between the age of one and two1 is #cj1jjj2 it is plain that the number who would die out of #hai1ejh will by the rule of three be #bg1hfc1 and consequently that the residue1 namely1 #gia1fae1 will remain alive1 and so enter on the age of two years4 ,this method being pursued through each and every age to the extreme term of life1 when none of the original million survive1 the result is a table of mortality in the form in which it is commonly presented in the works of writers on this branch of science4 ,in the table thus constructed there is a column containing the number of living persons who1 out of the original million1 lived to enter upon each and every year4 ,of this rank of numbers the difference between each term and its next succeeding one1 is the number who die in that particular interval3 that number is the measure of what is technically called the decrement of life for that particular year1 and the whole of the decrements for each and every year taken collectively is termed the decrement of life4 ,the decrement of life1 then1 is not only not the same as the law of mortality1 but is carefully to be distinguished from it4 ,the law of mortality is derived from observing the number who die out of one and the same number which is always supposed to enter on each and every year4 ,the decrement of life constitutes a rank of numbers arising out of the successive deaths2 that is1 out of the original million in the first year2 out of the survivors of that million in the second year2 out of the survivors of those survivors in the third year1 and so on4 ,in the first case the number of the living is always the same2 the number that die is the variable quantity3 in the second case the number of the living is the variable quantity1 while the number that die may remain pretty much the same for a succession of years2 and on casting the eye on the tables constructed in the ordinary mode1 it will be seen that the number often does remain the same for a considerable series of years4 ,we have said that life is a fluctuating quantity4 ,it fluctuates in different countries at the same period2 in the same country at different periods2 in the same country1 at the same period1 in different places2 in the same country1 at the same period1 in the same place1 among different classes2 in the same country1 at the same period1 in the same place1 among the same class1 at the different determinate stages of life4 ,some few of these fluctuations1 and more especially the last1 depend on the primary constitution of the organization in which life itself has its seat1 over which man has little or no control4 ,the greater part of them depend on external and adventitious agencies over which man has complete control4 ,human ignorance1 apathy1 and indolence1 may render the duration of life1 in regard to large classes and entire countries1 short2 human knowledge1 energy and perseverance1 may extend the duration of life far beyond what is commonly imagined4 ,it will be interesting and instructive to select a few of the more striking examples of this from the records we possess1 few and imperfect as they are1 in relation to this subject4 ,of the duration of life in the earlier periods of the history of the human race we know nothing with exactness1 though there are incidental statements which afford the means of deducing with some probability the rate of mortality in particular situations4 ,there has come down to us one document through ,domitius ,ulpianus1 a judge1 who flourished in the reign of ,alexander ,severus1 which enables us to form a probable conjecture at least of the opinion of the ,roman people of the value of life among the citizens of ,rome in that age4 ,it happened at ,rome as in other countries1 that when an estate came into the possession of an individual it was burthened with a provision for another person during the life of the latter1 a younger brother1 for example4 ,this provision was called by the ,romans an aliment4 ,no estate1 burthened with such a provision1 could be sold by the heir in possession1 unless the purchaser retained in his hands so much of the price as was deemed adequate to secure the regular and continuous payment of the aliment4 ,this imposed upon the ,romans the necessity of considering what the term of life would probably be from and after any given age4 ,what they did conceive that term to be is stated in a document of ,ulpianus1 recorded by ,justinian1 and given in the note below4#a ,this document imports that from infancy up to the age of #bj there should be allowed #cj years ,from #bj to #be #bh #be to #cj #be #cj to #ce #bb #ce to #dj #bj -------- ,from #ej to #ee #i #ee to #fj #g ,and at all ages above #fj #e ,but between #dj and #ej1 as many years were to be allowed as the age of the party fell short of #fj1 deducting one year4 ,no clue has hitherto been obtained to the discovery of the real meaning of this document4 ,it is1 however1 highly probable that the ,romans had fallen on one of the two methods of measuring the value of life already explained2 namely1 that termed the ,probability of ,life4 ,of the two modes of determining the value of life1 the probability was more likely to occur to a ,roman judge than the expectation4 ,he had no tables1 no registers to guide him4 ,what course1 then1 would he be likely to take8 ,probably he would form a list of his own school-fellows and others within his own knowledge1 of the age1 say1 of twenty4 ,by prevailing on persons of his own age1 on whose correctness he could rely1 to draw out similar lists1 he might accumulate some thousand names4 ,in this list it is probable that the male sex alone would be included1 on account of the greater ease of ascertaining both their exact age and the exact date of their death4 ,for the same reason1 it is probable that the list would consist only of the nobility and the inhabitants of towns4 ,having thus completed his list1 the next step would be to frame another list of all who died at the age of twenty-one2 and next1 another list of all who died at the age of twenty-two1 and so on through each and every year of life4 ,now by subtracting the number in the list1 ,no4 #a1 that is1 those who died between twenty and twenty-one1 from the number who originally started at twenty1 which1 in other words1 would be to find the decrement of life1 in the mode already explained1 he would see how many lived to commence the age of twenty-one1 and so on1 through each year of life4 ,but this would be to construct a table1 showing the probable duration of life2 that is1 a table from which he could observe at what advanced age the number originally starting at twenty1 and so on1 came to diminish to one-half1 when it would naturally occur to him that it is an equal wager whether such younger life would or would not be in existence at the advanced age so ascertained4 ,if we suppose this to have been the method actually adopted by the ,roman judge1 and apply it to the table of ,ulpianus1 the result obtained is consistent in an extraordinary degree1 and is highly interesting4 ,there is reason to believe that the mortality at present throughout ,europe1 taking all countries together1 including towns and villages1 and combining all classes into one aggregate1 is one in thirty-six4 ,sssmilch1 a celebrated ,german writer1 who flourished about the middle of the last century1 estimated it at this average at that period4 ,the result of all ,mr4 ,finlaison's investigations is a conviction that the average for the whole of ,europe does not materially differ at the present time4 ,he has ascertained by an actual observation1 that in the year #ahcb it was precisely this in the town of ,ostend4 ,taking this town1 then1 as the subject of comparison1 it is found that the probable duration of life among the male sex at ,ostend exceeds the ,roman allowance by the following number of years2 namely1 ,at the age of #ag1 the excess in round numbers is #e years4 #bb #e #bg #e #cb #e #cg #c #db #c #dg #e #eb #e #eg #d #fb #d #fg #b #gb #a #gg #j ,but it is not improbable that the ,romans made some deduction from what they knew to be the real value of life among the citizens of ,rome1 on account of the use of the money appropriated to the aliment1 which the purchaser of the estate retained in his own hands4 ,it has been shown that the average mortality at present at ,ostend is one in thirty-six2 which is the same thing as to assert that a new-born child at ,ostend has an expectation of thirty-five and a half years of life4 ,the ,roman allowance from birth1 prim tate1 was thirty years4 ,if we suppose the ,romans deducted from the real value of life five and a half years for the interest of money1 it would bring the ,roman allowance and the duration of life at ,ostend to the same4 ,the like deduction at the age of seventeen would likewise bring the probability of life in both cases to the same4 ,it is not likely that the ,romans1 without any record of the individual facts1 and acting only on a general principle of utility1 the best they could find1 would make any variation for the intermediate years of childhood and youth3 consequently the presumption is1 that the duration of life at ,rome1 #acjj years ago1 was very much the same as it is throughout ,europe at the present day4 ,this estimate1 however1 for the reasons already assigned1 includes only the resident citizens of ,rome1 the male sex1 and the higher classes4 ,what the mortality was at ,rome among the lower class1 including the slaves--what it was in the ,roman provinces1 and in the less civilized countries of that age--we have no means of forming even a conjecture4 ,what it was in ,europe during the succeeding ages of barbarism we do not know4 ,in civilized ,rome1 the value of life had probably reached a very high point2 in barbarian ,europe we may be sure it fell to an exceedingly low point4 ,from that low point1 in civilized ,europe1 it has been slowly but gradually rising1 until1 in modern times1 the whole mass of the ,european population has1 to say the very least1 reached the highest point attained by the select class in ancient ,rome4 ,but in some favoured spots in ,europe1 the whole mass has advanced considerably beyond the select class in ancient ,rome4 ,in ,england1 for example1 the expectation of life1 at the present day1 for the mass of the people1 as compared with that of the mass at ,ostend1 which1 as has been shown1 is the same as that of the whole of ,europe1 is as follows3-- ,at birth #da years4 ,at #ab #df #ag #da #bb #ch #bg #ce #cb #cb #cg #bh #db #be #dg #bb #eb #ai #eg #af #fb #ac #fg #aj #gb #h #gg #f ,it should be borne in mind that the females of the mass exceed in duration the lives of the males at every age by two or three years4 ,the earliest statistical document bearing on the rate of mortality1 in any ,european nation1 emerging from the state of barbarism1 appears to be a manuscript of the fourteenth century1 relating to the mortality of ,paris1 from which ,m4 ,villerm has calculated that the mortality of ,paris at that period was one in sixteen4 ,how the individual facts contained in this manuscript were collected1 from which ,m4 ,villerm's calculation is made1 does not appear2 and it makes the mortality so excessive as to be altogether incredible4 ,yet a statement scarcely less extraordinary is made with regard to ,stockholm1 in the middle of the last century4 ,from a table given by ,dr4 ,price1 vol4 ii41 p4 #daa1 it appears that1 for all ,sweden1 between the years #agef and #agfc1 the expectation of life ,of males at birth1 was ,females1 #cc years4 #ce years4 while at the same time it was at ,stockholm1 ,for males at birth1 ,females1 #ad years4 #ah years4 ,whereas1 for the twenty years preceding #ahjj1 it was1 for all ,sweden1 at birth1 ,males1 ,females1 #cd4 #cg4 ,hitherto1 in all places which man has made his abode1 noxious agents have been present which act injuriously upon his body1 tending to disturb the actions of its economy1 and ultimately to extinguish life4 ,all these noxious agents1 of whatever name or quality1 may be included under the term ,causes of ,mortality4 ,inherent in the constitution of the body are conservative powers1 the tendency of which is to resist the influence of these causes of mortality4 ,the actual mortality at all times will of course be according to the relative strength of these destructive agents1 and the relative weakness of these conservative powers4 ,there are states of the system tending to enfeeble these conservative powers4 ,such states become tests1 often exceedingly delicate1 of the presence and power of the destructive agents to which the body is exposed2 and such1 more especially1 are1 the states of parturition1 infancy1 and sickness4 ,during the prevalence of these states1 in which the conservative powers of the body are weak1 life is destroyed by causes which do not prove mortal in other conditions of the system4 ,accordingly1 in every age and country1 the rate of mortality among its lying-in women1 its infants and its sick1 may be taken as a measure of the degree in which the state of the whole population is favourable or unfavourable to life4 ,the change that has taken place in the condition of lying-in women during the last century in all the nations of ,europe cannot be contemplated without astonishment4 ,the mortality of lying-in women in ,france1 at the ,htel ,dieu of ,paris1 in #aghj1 is stated to have been one in #ae4 ,in #ahag1 for the whole kingdom of ,prussia1 including all ranks1 it was one in #aab4 ,in ,england1 in the year #agej1 at the ,british ,lying-in ,hospital of ,london1 it was one in #db2 in #aghj1 it diminished to one in #fj2 in the years between #aghi and #agih1 it further decreased to one in #bhh2 in #ahbb1 at the ,lying-in ,hospital of ,dublin1 it was no more than one in #bbc2 while during the last fifteen years at ,lewes1 a healthy provincial town1 out of #bdaj cases there have been only two deaths1 that is1 one in #abje4 ,there is no reason to suppose that the mortality in the state of parturition is less at ,lewes than in any other equally healthy country-town in ,england4 ,equally striking is the proof of the diminished violence of the prevalent causes of disease and death derived from the diminished mortality of children1 the vital power of resistance being always comparatively weak in the human infant1 and consequently1 the agents that prove destructive to life exerting their main force on the new born1 and on those of tender age4 ,from mortuary tables1 preserved with considerable accuracy at ,geneva since the year #aeff1 it appears that at the time of the ,reformation one-half of the children born died within the sixth year2 in the seventeenth century1 not till within the twelfth year2 in the eighteenth century1 not until the twenty-seventh year2 consequently1 in the space of about three centuries1 the probability that a child born in ,geneva would arrive at maturity has increased fivefold4 ,in the present day1 at ,ostend1 only half of the new-born children attain the age of thirty2 whereas1 in ,england1 they attain the age of forty-five4 ,no less remarkable is the progressive diminution of mortality among the sick of all ages4 ,hippocrates has left a statement1 which has come down to our times1 of the history and fate of forty-two cases of acute disease4 ,out of this number1 thirty-seven were cases of continued fever2 of these thirty-seven febrile cases twenty-one died1 above half of the whole4 ,the remaining five were cases of local inflammation1 and of these four were fatal2 thus1 of the whole number of the sick 7forty-two71 twenty-five were lost4 ,now1 even in the ,fever ,hospital of ,london1 to which1 for the most part1 only the worst cases that occur in the metropolis are sent1 and even of these many not until so late a period of the disease that all hope of recovery is extinct1 the mortality ranges in different years from one in six to one in twelve2 and for a period of ten consecutive years1 it is no more than one in seven2 while1 in the ,dublin ,fever ,hospital1 where most of the cases are sent very early1 the average mortality from #ahjd to #ahab was one in twelve4 ,at the ,imperial ,hospital at ,petersburg1 the average mortality for fourteen years1 ending in #ahag1 was one in four and a half4 ,in the ,charit of ,berlin1 on an average of twenty years1 from #agif to #ahag1 it was one in six4 ,at ,dresden1 it was one in seven2 at ,munich1 it was one in nine1 the lowest of any hospital of equal size in ,germany4 ,in the year #afhe1 the average mortality at ,st4 ,bartholomew's and ,st4 ,thomas's ,hospitals was from one in seven to one in ten4 ,during the ten years from #aggc to #aghc1 it decreased to one in fourteen4 ,from #ahjc to #ahac1 it was one in sixteen4 ,the average for fifty years from #agfd to #ahac1 was one in fifteen4 ,in the smaller towns1 the mortality is still less4 ,it is less in ,edinburgh and ,dublin than in ,london2 while in the hospital at ,bath during #ahbg1 even among the physician's patients1 the mortality was only one in twenty4 ,in the ,german provincial towns1 the diminution is still more remarkable4 ,in the hospital at ,gottingen1 for example1 it is only one in twenty-one4 ,if the accuracy of these statements could be relied on1 they would not only afford striking illustrations of the well-known fact that extraordinary differences prevail in the rate of mortality in different places1 at different periods1 and under different circumstances2 but they would further prove that1 during the last century1 a steady and progressive diminution of mortality has taken place in all the countries of ,europe4 ,but of the truth of this there is much more certain evidence than can be derived from calculations1 the trustworthiness of the data of which is not established1 and the correctness of the calculators not known4 ,both the fluctuations of mortality and the increase in the value of life in the different countries of ,europe1 from the earliest period when statistical facts began to be collected and compared1 are exhibited in a striking point of view in the following table1 drawn up by ,mr4 ,finlaison4 ,the facts relating to selected lives and to the mass of the people are distinguished from each other1 in order that they may be contrasted4 ,the data are derived from the most authentic sources1 and the calculations are made by men of the highest authority4 ,let it be conceived1 that at each #ej #ee #fj #fe #gj #ge #hj #he of the following ages1 viz4 ,yrs4,yrs4,yrs4,yrs4,yrs4,yrs4,yrs4,yrs4 ,the average duration of ,human ,life of both sexes collectively may thenceforward be assumed at a maximum of#b #bc #ai #af #ac #aa #h #f #c ,by how many weeks does the average duration which results from the most authentic ,tables at present known fall short of the maximum ,term thus assumed8 ,among the higher classes of people exclusively4 ,answer4 ,name of the ,observer4 ,wks4 ,wks4 ,wks4 ,wks4 ,wks4 ,wks4 ,wks4 ,wks4 ,in ,england-- ,among the ,government ,annuitants1 between #agge and #ahbb ,john ,finlaison4 #ce #a #g #aj #dg #aa #ad #ec ,among the ,lives assured at the ,equitable ,office1 between #agfj and #ahcd ,arthur ,morgan4 #aai #hc #hg #ha #if #cc #aj #bg ,among the ,nominees of the ,tontine of #afic-- between that year and #agge ,john ,finlaison4 #bfi #aie #agj #ada #aeg #aaj #ij #hi ,in ,france-- ,among the ,nominees of the ,tontine of #afic-- between that year and #agde ,m4 de ,parcieux4 #acc #hh #hg #hf #aah #gj #ee #fe ,in ,holland-- ,among the ,public ,annuitants1 between #afae and #agdj ,m4 ,kersseboom4 #ahf #aah #ajd #ge #if #fa #dh #hd ,in regard to the mass of the people4 ,in ,breslau in ,silesia1 between #agjj and #agbe1 ,dr4 ,halley4 #bge #baa #aha #aej #aff #ajj #cf #acg ,in ,sweden1 between #agge and #agie1 ,m4 ,nicander1 and ,mr4 ,milne4 #bjg #afa #afd #adf #aef #id #fj #fj ,in ,northampton1 in ,england1 between #agce and #aghj1 ,dr4 ,price4 #bji #agh #ade #aaj #abe #gf #fe #he ,in ,carlisle1 in ,england1 between #aggi and #aghg1 ,dr4 ,heysham1 and ,mr4 ,milne4 #ih #gd #hf #fc #id #eb #bf #df ,in all ,england and ,wales1 between #ahaa and #ahca1 ,john ,finlaison4 #ajj #ei #fe #eh #hg #dh #cg #di ,in the town of ,ostend1 in ,flanders1 between #ahje and #ahcb1 ,john ,finlaison4 #bgf #baj #ahd #adf #adc #gf #ej #ge ,in all ,belgium1 between #agbe and #ahcb1 ,m4 ,quetelet4 #ahc #acc #acc #aag #aab #hd #ej #fa ,let us trace from this table the differences that have taken place1 in different countries at different periods1 in the duration of life at a given age4 ,let us take the age given in the first column1 namely1 fifty4 ,assuming1 then1 the highest degree of longevity hitherto attained at the age of fifty to be twenty-three years1 it appears that1 between the years #agjj and #agbe1 the mass of the people in ,breslau1 in ,silesia1 fell short of reaching this period by #bge weeks2 the inhabitants of the town of ,ostend in ,flanders1 between #ahje and #ahcb1 by #bgf weeks2 the nominees of the tontine of ,england1 between the years #afic and #agge1 by #bfi weeks2 the inhabitants of the town of ,northampton in ,england1 between #agce and #aghj1 by #bji weeks2 the mass of the people in ,sweden1 between #agge and #agie1 by #bjg weeks2 the public annuitants of ,holland1 between #afae and #agdj1 by #ahf weeks2 the inhabitants of all ,belgium1 between #agbe and #ahcb1 by #ahc weeks2 the persons assured at the ,equitable ,office1 between #agfj and #ahcd1 by #aai weeks2 the inhabitants of all ,england and ,wales1 between #ahaa and #ahca1 by #ajj weeks2 the ,english government annuitants1 between #agge and #ahcb1 only by #ce weeks4 ,from these statements1 it appears that1 towards the close of the seventeenth century1 the duration of life in ,england was considerably less than in ,france3 less even than in ,holland nearly a century earlier4 ,thus1 the nominees of the tontine of ,france1 between the years #afic and #agde1 at the age of fifty1 according to ,m4 ,de ,parcieux1 fell short of the maximum longevity by #acc weeks2 the public annuitants of ,holland1 seventy-eight years before1 namely1 between the years #afae and #agdj1 according to ,m4 ,kersseboom1 fell short of the maximum longevity by #ahf weeks2 whereas1 the nominees of the tontine of ,england1 between the years #afic and #agge1 according to ,mr4 ,finlaison1 fell short of it by #bfi weeks2 a difference nearly double that of ,holland1 and quite double that of ,france in persons of the corresponding rank in society4 ,since that period1 surprising changes have taken place in all the nations of ,europe2 but in none has the change been so great as in ,england4 ,from that period1 when its mortality exceeded that of any great and prosperous ,european country1 its mortality has been steadily diminishing1 and at the present time the value of life is greater in ,england than in any other country in the world4 ,not only has the value of life been regularly increasing until it has advanced beyond that of any country of which there is any record2 but the remarkable fact is established1 that the whole mass of its people now live considerably longer than its higher classes did in the seventeenth and eighteenth centuries4 ,thus1 by inspecting the preceding table1 it will be seen that between the years #afic and #agae1 the nominees of the tontine of ,england1 at the age of fifty1 fell short of the maximum longevity by #bfi weeks2 whereas1 the mass of the people in all ,england and ,wales1 between the years #ahaa and #ahca1 fell short of it only by #ajj weeks2 the entire mass having not only reached the select class1 but absolutely advanced beyond it by #afi weeks4 ,there cannot be a more interesting and instructive thing than to connect these facts with their causes4 ,this will be attempted in a subsequent part of this work2 but the reader will be incomparably better prepared for the investigation when the processes of life have been explained1 and the influence of physical and moral agents upon them traced4 ,and with this exposition we now proceed4 ,,chapter ,v4 ,ultimate elements of which the body is composed--,proximate principles--,fluids and solids--,primary tissues--,combinations--,results--,organ s1 systems1 apparatus--,form of the body--,division into head1 trunk1 and extremities--,structure and function of each--,regions--,seats of the more important internal organs4 #a4 ,the ultimate elements of which the human body is composed are azote1 oxygen1 and hydrogen 7gaseous fluids72 and carbon1 phosphorus1 calcium1 sulphur1 sodium1 potassium1 magnesium1 and iron 7solid substances74 ,these bodies are called elementary and ultimate1 because they are capable of being resolved by no known process into more simple substances4 #b4 ,these elementary bodies unite with each other in different proportions1 and thus form compound substances4 ,a certain proportion of azote uniting with a certain proportion of oxygen1 hydrogen1 and carbon1 forms a compound substance possessing certain properties4 ,another proportion of azote uniting with a different proportion of oxygen1 hydrogen1 and carbon1 forms another compound substance possessing properties different from the former4 ,oxygen1 hydrogen1 and carbon1 uniting in still different proportions without any admixture of azote1 form a third compound possessing properties different from either of the preceding4 ,the compounds thus formed by the primary combinations of the elementary substances with each other are called ,,proximate ,,principles4 #c4 ,each proximate principle constitutes a distinct form of animal matter1 of which the most important are named gelatin1 albumen1 fibrin1 oily or fatty matter1 mucus1 urea1 pichromel1 osmazome1 resin1 and sugar4 #d4 ,by chemical analysis it is ascertained that all the proximate principles of the body1 however they may differ from each other in appearance and in properties1 are composed of the same ultimate elements4 ,gelatin1 for example1 consists 7in #ajj parts7 of azote #af-ihh_/ajjj1 oxygen #bg-bjg_/ajjj1 hydrogen #g-iad_/ajjj1 carbon #dg-hha_/ajjj parts4 ,the elementary bodies uniting in the above proportions form an animal substance1 soft1 tremulous1 solid1 soluble in water1 especially when heated1 and on cooling1 which may be considered as its distinctive property1 separating from its solution in water into the same solid substance1 without undergoing any change in its chemical constitution4 #e4 ,again1 albumen consists of azote #ae-gje_/ajjj1 oxygen #bc-hgb_/ajjj1 hydrogen #g-edj_/ajjj1 carbon #eb-hhh_/ajjj1 parts4 ,the elementary bodies uniting in these different proportions1 there results a second proximate principle1 an adhesive fluid1 transparent1 destitute of smell and taste1 miscible in water1 but when subjected to a temperature of about #afe1 converted into a solid substance no longer capable of being dissolved in water4 ,this conversion of albumen from a fluid1 which is its natural state1 into a solid1 by the application of heat1 is called coagulation4 ,it is a process familiar to every one4 ,the white of egg is nearly pure albumen1 naturally a glary and adhesive fluid3 by boiling1 it is coagulated into a white and firm solid4 #f4 ,in like manner1 fibrin consists of azote #ai-icd_/ajjj1 oxygen #ai-fhe_/ajjj1 hydrogen #g-jba_/ajjj1 carbon #ec-cfj_/ajjj parts1 forming a solid substance of a pale whitish colour and firm consistence1 the peculiar character of which is its disposition to arrange itself into minute threads or fibres4 #g4 ,on the other hand1 fat or oil1 which is a fluid substance of a whitish yellow colour1 inodorous1 nearly insipid1 unctuous1 insoluble in water and burning with rapidity1 consists of a larger proportion of hydrogen1 a small proportion of oxygen1 and a still smaller proportion of carbon1 without any admixture of azote4 #h4 ,from this account of the composition of the proximate principles1 which it is not necessary to extend further1 it is manifest that all of them consist of the same ultimate elements1 and that they derive their different properties from the different proportions in which their elements are combined4 #i4 ,the ultimate elements that compose the body are never found in a separate or gaseous state1 but always in combination in the form of one or other of the proximate principles4 #aj4 ,in like manner1 the proximate principles never exist in a distinct and pure state1 but each is combined with one or more of the others4 ,no part consists wholly of pure albumen1 gelatin1 or mucus1 but albumen is mixed with gelatin1 or both with mucus4 #aa4 ,simple or combined1 every proximate principle assumes the form either of a fluid or of a solid1 and hence the most general and obvious division of the body is into fluids and solids4 ,but the terms fluid and solid are relative1 not positive2 they merely express the fact that some of the substances in the body are soft and liquid compared with others which are fixed and hard2 for there is no fluid1 however thin1 which does not hold in solution some solid matter1 and no solid1 however dense1 which does not contain some fluid4 #ab4 ,fluids and solids are essentially the same in nature2 they differ merely in their mode of aggregation2 hence the easy and rapid transition from the one to the other which incessantly takes place in the living body1 in which no fluid long remains a fluid1 and no solid a solid1 but the fluid is constantly passing into the solid and the solid into the fluid4 #ac4 ,the relative proportion of the fluids in the human body is always much greater than that of the solids2 hence its soft consistence and rounded form4 ,the excess1 according to the lowest estimate1 is as #f to #a1 and according to the highest1 as #aj to #a4 ,but the proportion is never constant2 it varies according to age and to the state of the health4 ,the younger the age1 the greater the preponderance of the fluids4 ,the human embryo1 when first perceptible1 is almost wholly fluid3 solid substances are gradually but slowly superadded1 and even after birth the preponderance is strictly according to age2 for in the infant1 the fluids abound more than in the child2 in the child1 more than in the youth2 in the youth1 more than in the adolescent2 in the adolescent1 more than in the adult2 and in the adult1 more than in the aged4 ,thus1 among the changes that take place in the physical constitution of the body in the progress of life1 one of the most remarkable is the successive increase in the proportion of its solid matter3 hence the softness and roundness of the body in youth2 its hard1 unequal1 and angular surface in advanced life2 its progressively increasing fixedness and immobility in old age1 and ultimate inevitable death4 #ad4 ,the fluids are not only more abundant than the solids1 but they are also more important1 as they afford the immediate material of the organization of the body2 the media by which both its composition and its decomposition are effected4 ,they bear nourishment to every part1 and by them are carried out of the system its noxious and useless matter4 ,in the brain they lay down the soft and delicate cerebral substance2 in the bone1 the hard and compact osseous matter2 and the worn-out particles of both are removed by their instrumentality4 ,every part of the body is a laboratory in which complicated and transforming changes go on every instant2 the fluids are the materials on which these changes are wrought2 chemistry is the agent by which they are effected1 and life is the governing power under whose control they take place4 #ae4 ,the fluids1 composed principally of water holding solid matter in solution1 or in a state of mechanical division1 either contribute to the formation of the blood1 or constitute the blood1 or are derived from the blood2 and after having served some special office in a particular part of the system1 are returned to the blood2 and according to the nature and proportion of the substances they contain1 are either aqueous1 albuminous1 mucous1 gelatinous1 fibrinous1 oleaginous1 resinous1 or saline4 #af4 ,when the analysis of the different kinds of animal matter that enter into the composition of the body has been carried to its ultimate point1 it appears to be resolvable into two primitive forms3 first1 a substance capable of coagulation1 but possessing no determinate figure2 and secondly1 a substance having a determinate figure and consisting of rounded particles4 ,the coagulable substance is capable of existing by itself2 the rounded particles are never found alone1 but are invariably combined with coagulated or coagulable matter4 ,alone or combined with the rounded particles1 the coagulable matter forms1 when liquid1 the fluids1 when coagulated1 the solids4 #ag4 ,when solid1 the coagulable substance is disposed in one of two forms1 either in that of minute threads or fibres1 or in that of minute plates or lamin2 hence every solid of the body is said to be either fibrous or laminated4 ,the fibres or lamin are variously interwoven and interlaced1 so as to form a net-work or mesh2 and the interspaces between the fibres or lamin are commonly denominated areol or cells 7fig4 ,,xvii74 #ah4 ,this concrete substance1 fibrous or laminated1 is variously modified either alone or in combination with the rounded particles4 ,these different modifications and combinations constitute different kinds of organic substance4 ,when so distinct as obviously to possess a peculiar structure and peculiar properties1 each of these modifications is considered as a separate form of organized matter1 and is called a ,,primary ,,tissue4 ,anatomists and physiologists have been at great pains to discriminate and classify these primary tissues2 for it is found that when employed in the composition of the body1 each preserves its peculiar structure and properties wherever placed1 however combined1 and to whatever purpose applied1 undergoing only such modification as its local connexions and specific uses render indispensable4 ,considering every substance employed in the construction of the body1 not very obviously alike1 as a distinct form of organized matter1 these primary tissues may be said to consist of five1 namely1 the membranous1 the cartilaginous1 the osseous1 the muscular1 and the nervous4 #ai4 ,the first primary tissue is the peculiar substance termed ,,membrane4 ,it has been already stated 7#af7 that one of the ultimate forms of animal matter is a coagulable substance1 becoming concrete or solid under the process of coagulation4 ,the commencement of organization seems to be the arrangement of this concrete matter into straight thready lines1 at first so small as to be imperceptible to the naked eye4 ,vast numbers of these threads successively uniting1 at length form a single thread of sufficient magnitude to be visible1 but still smaller than the finest thread of the silkworm4 ,if the length of these threads be greater than their breadth1 they are called fibres2 if1 on the contrary1 their breadth exceed their length1 they are termed plates or lamin4 ,by the approximation of these fibres or plates in every possible direction1 and by their accumulation1 combination1 and condensation1 is constituted the simplest form of organized substance1 the primary tissue called membrane4 #bj4 ,membrane once formed is extensively employed in the composition of the body3 it is indeed the material principally used in producing1 covering1 containing1 protecting1 and fixing every other component part of it4 ,it forms the main bulk of the cartilaginous tissue2 it receives into its cells the earthy matter on which depend the strength and hardness of the osseous tissue2 it composes the canals or sheaths in which are deposited the delicate substance of the muscular1 and the still more tender pulp of the nervous tissue2 it gives an external covering to the entire body2 it lines all its internal surfaces2 it envelopes all internal organs2 it enters largely as a component element into the substance of every organ of every kind2 it almost wholly constitutes all the internal pouches and sacs1 such as the stomach1 the intestines1 the bladder2 and all tubes and vessels1 such as arteries1 veins1 and lymphatics2 it furnishes the common substance in which all the parts of the body are1 as it were1 packed2 it fills up the interstices between them2 it fixes them in their several situations2 it connects them all together2 in a word1 it forms the basis upon which the other parts are superinduced2 or rather the mould into which their particles are deposited2 so that were it possible to remove every other kind of matter1 and to leave this primary tissue unaltered in figure and undiminished in bulk1 the general form and outline of the body1 as well as the form and outline of all its individual parts1 would remain unchanged4 #ba4 ,the properties which belong to membrane are cohesion1 flexibility1 extensibility1 and elasticity4 ,by its property of cohesion1 the several parts of the body are held together2 by its combined properties of cohesion1 flexibility1 and extensibility1 the body in general is rendered strong1 light1 and yielding1 while particular parts of it are made capable of free motion4 ,but elasticity1 that property by which parts removed from their situation in the necessary actions of life are restored to their natural position1 may be regarded as its specific property4 ,the varied purposes accomplished in the economy by the property of elasticity will be apparent as we advance in our subject4 ,meantime1 it will suffice to observe that it is indispensable to the action of the artery in the function of the circulation2 to the action of the thorax in the function of respiration2 to the action of the joints in the function of locomotion3 in a word1 to the working of the entire mechanism by which motion of every kind and degree is effected4 ,all these properties are physical1 not vital2 vital properties do belong even to this primary form of animal matter2 but they are comparatively obscure4 ,in the tissue with which organization commences1 and which is the least removed from an inorganic substance1 the properties that are prominent and essential are merely physical4 #bb4 ,by chemical analysis1 membrane is found to contain but a small proportion of azote1 the peculiar element of animal matter4 ,its proximate principles are gelatin1 albumen1 and mucus4 ,in infancy and youth1 gelatin is the most abundant ingredient2 at a more advanced period1 albumen predominates#c4 ,gelatin differs from albumen in containing a less proportion of azote and a greater proportion of oxygen2 on both accounts it must be regarded as less animalized4 ,thus animalization bears a certain relation to organization4 ,the simplest animal tissue is the least animalized1 and the least of all at the earliest period of life4 ,not only are the physical and mental powers less developed in the young than in the adult1 but the very chemical composition of the primary tissue of which the body is constructed is less characteristic of the perfect animal4 #bc4 ,membrane exists under several distinct forms2 a knowledge of the peculiarities of which will materially assist us in understanding the composition of the body4 ,the simplest form of membrane1 and that which is conceived to constitute the original structure from which all the others art produced1 is termed the cellular4 ,when in thin slices1 cellular membrane appears as a semi-transparent and colourless substance2 when examined in thicker masses1 it is of a whitish or greyish colour4 ,it consists of minute threads1 which cross each other in every possible direction1 leaving spaces between them1 and thus forming a mesh or net-work 7fig4 ,,xvii471 not unlike the spider's web4 ,the term cells1 given to these interspaces1 is employed rather in a figurative sense than as the expression of the fact2 for there are no such distinct partitions as the term cell implies4 ,the best conception that can be formed of the arrangement of the component parts of this structure is1 to suppose a substance consisting of an infinite number of slender thready lines crossing each other in every possible direction 7fig4 ,,xvii474 ,the interspaces between these lines during life1 and in the state of health1 are filled with a thin exhalation of an aqueous nature1 a vapour rather than a fluid1 rendering and keeping the tissue always moist4 ,this vapour consists of the thinner part of the blood1 poured into these interstitial spaces by a process hereafter to be described1 termed secretion4 ,when occupying those spaces1 it makes no long abode within them1 but is speedily removed by the process of absorption4 ,in health1 these two operations exactly equal each other2 but if any cause arise to disturb the equilibrium1 the vapour accumulates1 condenses and forms an aqueous fluid1 which distends the cells and gravitates to the most depending parts4 ,slightly organized as this tissue is1 and indistinct as its vita functions may be1 it is obvious that it must be the seat of at least two vital functions1 secretion and absorption4 ,illustration3 ,fig4 ,,xvii4 ,a single film of the cellular tissue lifted up and slightly distended4 #bd4 ,it is certain that the interspaces or cells of this membrane have no determinate form or size1 that they communicate freely with each other1 and that this communication extends over the whole body2 for if a limb which has been infiltrated be frozen1 a thousand small icicles will be formed1 assuming the shape of the containing cells1 some of which are found to be circular and others cylindrical1 and so on4 ,if air or water escape into any particular part of the body1 it is often effused over the whole extent of it1 and butchers are observed to inflate animals by making a puncture in some part where the cellular tissue is loose1 and from this one aperture the air is forced to the most distant parts of the body4 #be4 ,cellular membrane1 variously modified and disposed1 forms the main bulk of all the other solid parts of the body1 constituting their common envelope and bond of union1 and filling up all their interstices4 ,it is dense or loose1 coarse or fine1 according to its situation and office4 ,wherever it is subject to pressure1 it is dense and firm1 as in the palm of the hand and the sole of the foot2 around the internal organs it is more loose and delicate1 and it becomes finer and finer as it divides and subdivides1 in order to envelope the soft and tender structures of the body4 ,illustration3 ,fig4 ,,xviii4 ,a portion of cellular tissue1 very highly magnified1 showing the strings of globules of which its ultimate fibres are by some supposed to consist4 #bf4 ,according to some who have carefully examined with the microscope its component threads1 they consist of minute particles of a globular figure 7fig4 ,,xviii472 other microscopical observers regard the cellular threads as coagulated or condensed animal substance1 perfectly amorphous 7without form74 #bg4 ,every part of this tissue is penetrated by arteries1 veins1 absorbents1 and nerves1 endowing it with properties truly vital1 though in a less degree than any of the other primary tissues2 and varied and important as the uses are which it serves in the economy1 the most manifest1 though certainly not the only ones1 are those which depend upon its physical properties of cohesion1 flexibility1 extensibility1 and elasticity4 ,illustration3 ,fig4 ,,xix4 #a1 ,a portion of adipose tissue2 #b1 minute bags containing the fat2 #c1 a cluster of the bags1 separated and suspended4 #bh4 ,the tissue which contains the fat1 termed the adipose1 is the second form of membrane2 it is obviously a modification of the cellular1 from which it differs both in the magnitude of its fibres1 whence it constitutes a tougher and coarser web1 and in their arrangement2 for it is so disposed as to form distinct bags in which the fat is contained4 ,adipose tissue consists of rounded packets1 separated from each other by furrows 7fig4 ,,xix4 #b1 #b72 each packet is composed of small spheroidal particles 7fig4 ,,xix4 #b1 #b72 each particle is again divisible into still smaller grains1 which1 on minute inspection1 present the appearance of vesicles filled with the adipose matter 7fig4 ,,xix4 #c74 #bi4 ,the cells of the cellular tissue1 as has been shown 7#bd71 are continuous over the whole body2 but each adipose vesicle is a distinct bag1 having no communication whatever with any other 7fig4 ,,xix4 #b1 #b74 ,the cellular tissue is universally diffused2 but the adipose is placed only in particular parts of the body2 principally beneath the skin1 and more especially between the skin and the abdominal muscles1 and around some of the organs contained in the chest and abdomen1 as the heart1 the kidneys1 the mesentery1 and the omenta4 ,in most of these situations some portion of it is generally found1 whatever be the degree of leanness to which the body may be reduced2 while in the cranium1 the brain1 the eye1 the ear1 the nose1 and several other organs1 there is none1 whatever be the degree of corpulency4 ,the uses of the fat1 which are various1 will be stated hereafter4 #cj4 ,the third form of membrane is termed the serous4 ,like the adipose1 serous membrane is a modification of the cellular1 and1 like it also1 it is limited in its situation to particular parts of the body1 that is1 to its three great cavities1 namely1 the head1 the chest1 and the abdomen4 ,to the two latter it affords an internal lining1 and to all the organs contained in all the three cavities1 it affords a covering4 ,by its external surface it is united to the wall of the cavity or the substance of the organ it invests2 by its internal surface it is free and unattached2 whence this surface is in contact only with itself1 forming a close cavity or shut sac1 having no communication with the external air4 ,smooth and polished 7fig4 ,,xx471 it is rendered moist by a fluid which is supposed to be exhaled in a gaseous state from the serum of the blood2 and from this serous fluid the membrane derives its name4 ,illustration3 ,fig4 ,,xx4 ,a portion of intestine1 showing its external surface or serous coat4 #ca4 ,though thin1 serous membrane is dense1 compact1 and of great strength in proportion to its bulk3 it is extensible and elastic2 extensible1 for it expands with the dilatation of the chest in inspiration2 elastic1 for it contracts with the diminished size of the chest in expiration4 ,in like manner1 it stretches with the enlargement of the stomach during a hearty meal1 and contracts as the stomach gradually diminishes on emptying itself of its contents4 ,it is furnished with no blood-vessels large enough to admit the colouring matter of the blood2 but it is supplied with a great number of the colourless vessels termed exhalents1 with the vessels termed absorbents1 and with a few nerves4 ,it indicates no vital properties1 but those which are common to the simple form of the primary tissue4 ,its specific uses are to afford a lining to the internal cavities2 to furnish a covering to the internal organs2 by its polished and smooth surface1 to allow a free motion of those organs on each other1 and by the moisture with which it is lubricated1 to prevent them from adhering together1 however closely1 or for however long a period they may be in contact4 #cb4 ,the fourth form of membrane1 the fibrous1 named from the obvious arrangement of its component parts1 consists of longitudinal fibres1 large enough to be visible to the naked eye1 placed parallel to each other1 and closely united4 ,sometimes these fibres are combined in such a manner as to form a continuous and extended surface1 constituting a thin1 smooth1 dense1 and strong membrane1 such as that which lines the external surface of bones termed ,,periosteum1 or the internal surface of the skull 7dura mater74 ,at other times1 they form a firm and tough expansion 7aponeurosis7 which descends between certain muscles1 separating them from each other1 and affording a fixed point for the origin or insertion of neighbouring muscles2 or which is stretched over muscles1 and sometimes over even an entire limb1 in order to confine the muscles firmly in their situation1 and to aid and direct their action 7fig4 ,,xxvii474 ,fibrous membrane also constitutes the compact1 strong1 tough1 and flexible bands used for tying parts firmly together1 termed ,,ligaments1 principally employed in connecting the bones with each other1 and particularly about the joints2 and lastly1 fibrous membrane forms the rounded white cords in which muscles often terminate1 called ,,tendons 7fig4 ,,xxv41 ,,xxvi471 the principal use of which is to connect the muscles with the bones1 and to serve as cords or ropes to transmit the action of the muscle to a distant point1 in the accomplishment of which purposes their operation appears to be entirely mechanical4 #cc4 ,the fifth form of membrane1 the mucous 7fig4 ,,xxi471 derives its name from the peculiar fluid with which its surface is covered1 called mucus1 and which is secreted by numerous minute glands1 imbedded in the substance of the membrane4 ,as serous membrane forms a shut sac1 completely excluding the air1 mucous membrane1 on the contrary1 lines the various cavities which are exposed to the air1 such as the mouth1 the nostrils1 the wind-pipe1 the gullet1 the stomach1 the intestines1 the urinary organs1 and the uterine system4 ,its internal surface1 or that by which it is attached to the passages it lines1 is smooth and dense2 its external surface1 or that which is exposed to the contact of the air1 is soft and pulpy1 like the pile of velvet 7fig4 ,,xxi474 ,it bears a considerable resemblance to the external surface of the rind of the ripe peach4 ,illustration3 ,fig4 ,,xxi4 ,a portion of the stomach1 showing its internal surface or mucous coat4 ,unlike all the other tissues of this class1 the mucous membranes are the immediate seat of some of the most important functions of the economy2 in the lung1 of respiration2 in the stomach1 of digestion2 in one part of the intestine1 of chylification2 in another1 of excretion2 while in the mouth and nose1 they are the seat of the animal functions of taste and smell2 and they are highly organized in accordance with the importance of the functions they perform4 #cd4 ,the last form of membrane which it is necessary to our present purpose to particularize1 is that which constitutes the external covering of the body1 and which is called the skin4 ,the skin is everywhere directly continuous with the mucous membranes that line the internal passages1 and its structure is perfectly analogous4 ,both the external and the internal surface of the body may be said therefore to be covered by a continuous membrane1 possessing essentially the same organization1 and almost identically the same chemical composition4 ,the skin is an organ which performs exceedingly varied and important functions in the economy1 to the understanding of which it is necessary to have a clear conception of its structure2 some further account of it will therefore be required2 but this will be more advantageously given when the offices it serves are explained4 ,illustration3 ,fig4 ,,xxii4 ,portions of cartilage1 seen in section4 #ce4 ,such is the structure1 and such are the properties1 of the first distinct form of organized matter4 ,the second primary tissue1 termed the ,,cartilaginous 7fig4 ,,xxii471 is a substance intermediate between membrane and bone4 ,the nature of its organization is not clearly ascertained4 ,by some anatomists1 it is regarded as a uniform and homogeneous substance1 like firm jelly1 without fibres1 plates1 or cells2 others state that they have been able to detect in it longitudinal fibres1 interlaced by other fibres in an oblique and transverse direction1 but without determinate order4 ,all are agreed that it is without visible vessels or nerves3 not that it is supposed to be destitute of them1 but that they are so minute as to elude observation4 ,its manifest properties are wholly mechanical4 ,it is dense1 strong1 inextensible1 flexible1 and highly elastic4 ,it is chiefly by its property of elasticity that it accomplishes the various purposes it serves in the economy4 ,it is placed at the extremities of bones1 especially about the joints1 where1 by its smooth surface1 it facilitates motion1 and1 by its yielding nature1 prevents the shock or jar which would be produced were the same kind and degree of motion effected by a rigid and inflexible substance4 ,where a certain degree of strength with a considerable degree of flexibility are required1 it supplies the place of bone1 as in the spinal column1 the ribs and the larynx4 ,illustration3 ,fig4 ,,xxiii4 ,membranous portion of bone2 the osseous portion being so completely removed1 that the bone is capable of being tied in a knot4 #cf4 ,the third distinct form of organized matter is termed the ,,osseous tissue4 ,bone is composed of two distinct substances1 an animal and an earthy matter3 the former organic1 the latter inorganic4 ,the animal or organic matter is analogous both in its nature and in its arrangement to cellular tissue2 the earthy or inorganic matter consists of phosphoric acid combined with lime1 forming phosphate of lime4 ,the cellular tissue is aggregated into plates or lamin1 which are placed one upon another1 leaving between them interspaces or cells1 in which is deposited the earthy matter 7phosphate of lime74 ,if a bone1 for example1 the bone called the radius1 one of the bones of the fore-arm1 be immersed in diluted sulphuric1 nitric1 muriatic1 or acetic acid1 it retains its original bulk and shape2 it loses1 however1 a considerable portion of its weight1 while it becomes so soft and pliable1 that it may be tied in a knot 7fig4 ,,xxiii474 ,in this case1 its earthy matter is removed by the agency of the acid1 and is held in solution in the fluid2 what remains is membranous matter 7cellular tissue74 ,if the same bone be placed in a charcoal fire1 and the heat be gradually raised to whiteness1 it appears on cooling as white as chalk2 it is extremely brittle2 it has lost much of its weight1 yet its bulk and shape continue but little changed4 ,in this case1 the membraneous matter is wholly consumed by the fire1 while the earth is left unchanged 7fig4 ,,xxiv474 ,every constituent atom of bone consists1 then1 essentially of animal and earthy matter intimately combined4 ,a little more than one-third part consists of animal matter 7albumen71 the remaining two-thirds consist of earthy matter 7phosphate of lime72 other saline substances1 as the fluate of lime and the phosphate of magnesia1 are also found in minute quantity1 but they are not peculiar to bone4 ,illustration3 ,fig4 ,,xxiv4 ,earthy portion of bone4 #cg4 ,in general1 the osseous tissue is placed in the interior of the body4 ,even when bone approaches the surface1 it is always covered by soft parts4 ,it is supplied with but few blood-vessels1 with still fewer nerves1 with no absorbents large enough to be visible1 so that though it be truly alive1 yet its vital properties are not greatly developed4 ,the arrangement of its component particles is highly curious2 the structure1 the disposition1 and the connexion of individual bones afford striking examples of mechanism1 and accomplish most important uses in the economy2 but those uses are dependent rather upon mechanical than vital properties4 ,the chief uses of bone are-- #a4 ,by its hardness and firmness to afford a support to the soft parts1 forming pillars to which the more delicate and flexible organs are attached and kept in their relative positions4 #b4 ,to defend the soft and tender organs by forming a case in which they are lodged and protected1 as that formed by the bones of the cranium for the lodgment and protection of the brain 7fig4 ,,xlvii472 by the bones of the spinal column for the lodgment and protection of the spinal cord 7fig4 ,,xlviii472 by the bones of the thorax 7fig4 ,,lix471 for the lodgment and protection of the lungs1 the heart1 and the great vessels connected with it 7fig4 ,,lix474 #c4 ,by affording fixed points for the action of the muscles1 and by assisting in the formation of joints to aid the muscles in accomplishing the function of locomotion4 #ch4 ,all the primary tissues which have now been considered consist of precisely the same proximate principles4 ,albumen is the basis of them all2 with the albumen is always mixed more or less gelatin1 together with a minute quantity of saline substance3 to the osseous tissue is superadded a large proportion of earthy matter4 ,with the exception of the mucous1 the organization of all these tissues is simple2 their vital properties are low in kind and in degree2 their decided properties are physical1 and the uses they serve in the economy are almost wholly mechanical4 ,illustration3 ,fig4 ,,xxv4 ,portion of a muscle2 showing 7a7 the muscular fibres and their parallel direction2 and 7b7 the termination of the fibres in tendon4 #ci4 ,but we next come to a tissue widely different in every one of those circumstances1 a tissue consisting of a new kind of animal matter1 and endowed with a property not only peculiar to itself1 but proper to living substance1 and characteristic of a high degree of vital power4 ,,muscular ,,tissue1 the fourth distinct form of animal matter1 commonly known under the name of flesh1 is a substance resembling no other in nature4 ,it consists of a soft and pulpy substance1 having little cohesive power1 arranged into fibres which are distinctly visible to the naked eye1 and which are disposed in a regular and uniform manner1 being placed close and parallel to each other 7fig4 ,,xxv474 ,these fibres are every where pretty uniformly the same in shape1 size1 and general appearance1 being delicate1 soft1 flattened1 and though consisting only of a tender pulp1 still solid 7fig4 ,,xxv474 ,when examined under the microscope1 fibres1 which to the naked eye appear to be single threads1 are seen to divide successively into smaller threads1 the minutest or the ultimate division not exceeding1 as is supposed1 the #dj1jjjth part of an inch in diameter4 ,on the other hand1 the fibres which are large enough to be visible to the naked eye1 are obviously aggregated into bundles of different magnitude in different muscles1 but always of the same uniform size in the same muscle 7fig4 ,,xxv474 ,illustration3 ,fig4 ,,xxvi4 ,two portions of muscle2 one of which1 a1 is covered with membrane2 the other1 b1 is uncovered2 c1 the muscular fibres terminating in tendon4 #dj4 ,the ultimate thread1 or the minutest division of which the muscular fibre is susceptible1 is called a filament2 the smallest thread which can be distinguished by the naked eye is termed a fibre 7fig4 ,,xxvi472 and the bundle which is formed by the union of fibres is denominated a fasciculus4 ,the proper muscular substance is thus arranged into three distinct forms progressively increasing in size1--the filament1 the fibre1 and the fasciculus4 ,the filament1 the fibre1 the fasciculus1 as well as the muscle itself1 formed by the aggregation of fasciculi1 is each inclosed in its own distinct sheath of cellular membrane 7fig4 ,,xxvi4 a74 ,illustration3 ,fig4 ,,xxvii4 ,portion of a muscle enclosed in a sheath of fascia or aponeurosis4 #da4 ,the composition of the ultimate filament has been very carefully examined by many distinguished physiologists with microscopes of high magnifying power4 ,under some of these microscopes the filament appears to consist of a series of rounded particles or globules of the same size as the particles of the blood when deprived of their colouring matter1 so that it looks like a string of pearls 7fig4 ,,xxviii471 each globule being commonly stated to be about the #bjjjth part of an inch in diameter4 ,but it is now pretty generally agreed that this globular appearance of the ultimate muscular fibre vanishes under the more improved microscopes of the present day1 and1 as viewed by the latter1 appears as a peculiar pulpy substance arranged into threads of extreme minuteness1 placed close and parallel to each other1 intersected by a great number of delicate lines passing transversely across the muscular threads 7fig4 ,,xxix471 ,illustration3 ,fig4 ,,xxviii4 ,ultimate fibres of muscle1 very greatly magnified2 showing the strings of globules of which they are supposed by some to consist4 #db4 ,with the exception of the organs of sense1 the muscular tissue is more abundantly supplied with arteries1 veins1 and nerves1 than any other substance of the body4 ,every ultimate thread or filament appears to be provided with the ultimate branch of an artery1 vein1 and nerve4 ,these vessels are seen ramifying on the surface of the delicate web of membrane that incloses the pulp1 but cannot be traced into it4 ,illustration3 ,fig4 ,,xxix4 ,the appearance of the ultimate muscular fibres and of their transverse lines1 as seen under the microscope of ,mr4 ,lister1 when the object is magnified #ejj diameters4 #dc4 ,the proximate principle of which the muscular pulp is composed is fibrin4 ,from the pulp1 when inclosed in its sheath of membrane1 albumen1 jelly1 various salts1 and a peculiar animal extract called osmazome1 are also obtained2 but these substances are probably derived from the membranous1 not the muscular1 matter4 ,fibrin contains a larger proportion of azote1 the element peculiar to the animal body1 and by the possession of which its chemical composition is distinguished from that of the vegetable1 than any other animal substance4 ,illustration3 ,fig4 ,,xxx4 ,portion of the trunk of a nerve2 dividing into branches4 #dd4 ,muscular tissue possesses a slight degree of cohesion1 a high degree of flexibility and extensibility1 but no degree of elasticity2 for although muscle1 considered as a compound of muscular substance and membrane1 be highly elastic1 yet this property is probably altogether owing to the membranous matter in which it is enveloped4 ,its peculiar and distinctive property is vital1 not physical1 and consists in the power of diminishing its length1 or of contracting or shortening itself on the application of a stimulus4 ,this property1 which is termed contractility1 is the great1 if not the sole source of motion in the body4 ,without doubt1 elasticity and gravity1 under the generating and controlling powder of contractility1 aid in accomplishing various kinds of motion4 ,thus membranes1 tendons1 ligaments1 cartilages1 and bones1 by their physical and mechanical properties1 modify1 economize1 facilitate1 concentrate and direct the motive power generated by the pure muscular substance2 but still the only real source of motion in the body is muscular tissue1 and the only mode in which motion is generated is by contractility4 ,this will be more fully understood hereafter4 ,illustration3 ,fig4 ,,xxxi4 ,ultimate fibres of nerve1 very highly magnified2 showing the strings of globules of which they consist4 #de4 ,the last primary tissue1 termed the ,,nervous1 is equally distinct in nature and peculiar in property4 ,it consists of a soft and pulpy matter1 of a brownish white colour 7fig4 ,,xxx474 ,according to some1 the nervous1 like the muscular pulp1 is composed of minute globules1 arranged in the same manner like a string of pearls 7fig4 ,,xxxi472 according to others1 it consists of solid elongated threads1 of a cylindrical form1 differing in thickness from that of a hair to the finest fibre of silk4 ,the pulp1 whatever its form of aggregation1 is inclosed in a sheath of delicate cellular tissue4 ,this external or containing membrane is called the neurilema1 or the nerve-coat2 the internal or contained substance1 the proper nervous matter1 is termed the nerve-string4 ,the nerve-string1 enveloped in its nerve-coat1 constitutes the nervous filament4 ,as in the muscle1 so in the nerve1 many filaments unite to form a fibre1 many fibres to form a fasciculus1 and many fasciculi to form the large cord termed a nerve4 ,moreover1 as in the muscle1 so in the nerve1 the filament1 the fibre1 the fasciculus1 the nervous cord itself1 are each enveloped in its own distinct sheath of cellular membrane2 but the arrangement of the nervous fibres differs from that of the muscular in this1 that though the nervous fibres are placed in juxtaposition1 yet they do not1 like the muscular1 maintain through their entire course a parallel disposition1 but cross and penetrate each other1 so as to form an intimate interlacement 7fig4 ,,xxxii474 ,illustration3 ,fig4 ,,xxxii4 ,nervous fibres1 deprived of their neurilema and unravelled1 showing the smaller threads1 or filaments1 of which the fibres consist4 #df4 ,the nervous pulp is at least as liberally supplied with blood-vessels as the muscular2 the vessels are spread out upon the nerve-coat1 in which they divide into innumerable branches of extreme minuteness1 the distribution of which is so perfect1 that there is not a particle of nervous matter which is not supplied both with an arterial and a venous vessel4 ,hence the neurilema is not merely a sheath containing and protecting the nervous pulp1 but it affords an extended mechanical surface for sustaining the arterial vessels1 from which the pulp is probably secreted1 and certainly nourished4 #dg4 ,albumen1 in conjunction with a peculiar fatty matter1 constitutes the chief proximate principles of which the nervous tissue is composed4 ,to these are added a small proportion of the animal substance termed osmazome1 a minute quantity of phosphorus1 some salts1 and a very large proportion of water2 for out of one hundred parts of nervous substance1 water constitutes as much as eighty4 ,its peculiar vital property is sensibility2 and as all motion depends on the contractility of the muscular fibre1 so all sensation depends on the sensibility of the nervous substance4 #dh4 ,such are the primary tissues1 or the several kinds of organized matter of which the body is composed2 and from this account it is obvious that they consist of three only--namely1 the concrete matter forming the basis of membrane1 the pulpy matter forming the proper muscular substance1 and the pulpy matter forming the proper nervous substance4 ,of these three kinds of animal matter the component parts of the body consist4 ,in combining to form the different structures1 these primary substances are intermixed and arranged in a great variety of modes2 and from these combinations and arrangements result either an organ1 a system1 or an apparatus4 #di4 ,as filaments unite to form fibres1 and fibres to form tissues1 so tissues unite to form organs3 that is1 bodies having a determinate size and figure1 and capable of performing specific actions4 ,the cellular1 the muscular1 and the nervous tissues are not organs2 membranes1 muscles1 and nerves are organs4 ,the tissue1 the simple animal substance1 is merely one of the elements of which the organ is composed2 the organ is compounded of several of those simple substances1 arranged in a determinate manner1 and moulded into a given shape1 and so constituting a specific instrument4 ,the basis of the muscle is muscular tissue2 but to this are added1 invariably1 membrane1 often tendon1 and always vessels and nerves4 ,it is this combination that forms the specific instrument called a muscle1 and that renders it capable of performing its specific action4 ,and every such combination1 with its appropriate endowment1 constitutes an organ4 #ej4 ,organs are arranged into groups or classes1 according as they possess an analogous structure1 and perform an analogous function2 and this assemblage constitutes a ,,system4 ,all the muscles of the body1 for example1 whatever their size1 form1 situation1 or use1 have an analogous structure1 and perform an analogous function1 and hence are classed together under the name of the muscular system4 ,all the bones1 whatever their figure1 magnitude1 density1 position1 or office1 are analogous in structure and function2 and hence are classed together under the name of the osseous system4 ,for the same reason1 all the cartilages1 ligaments1 vessels and nerves1 form respectively the cartilaginous1 ligamentous1 vascular and nervous systems4 #ea4 ,an ,,apparatus1 on the contrary1 is an assemblage of organs1 it may be differing widely from each other in structure1 and exercising various and even opposite functions2 but all nevertheless concurring in the production of some common object4 ,the apparatus of nutrition consists of the organs of mastication1 deglutition1 digestion1 absorption1 and assimilation4 ,among the individual organs which concur in carrying on these functions may be reckoned the lips1 the teeth1 the tongue1 the muscles connected with the jaws1 the gullet1 the stomach1 the duodenum1 the small intestines1 the pancreas1 the liver1 the lacteal vessels1 the mesenteric glands1 and the lungs4 ,many of these organs have no similarity in structure1 and few have any thing analogous in function2 yet all concur1 each in its appropriate mode and measure1 to the conversion of the aliment into blood4 ,in the apparatus of respiration1 in that of circulation1 of secretion1 of excretion2 in the apparatus of locomotion1 in the apparatus of sensation1 and more especially in the apparatus of the specific sensations1--vision1 hearing1 smell1 taste1 touch1 organs are combined which have nothing in common but their concurrence in the production of a common end3 but this concurrence is the principle of their combination2 and the individual organs having this conjoint operation1 taken together1 constitute an apparatus4 #eb4 ,a clear idea may now be affixed to the terms structure and organization4 ,structure may be considered as synonymous with arrangement2 the disposition of parts in a determinate order2 that which is constructed or built up in a definite mode1 according to a determinate plan4 ,the arrangement of the threads of the cellular web into areol or cells2 the combination of the primary threads into fibres or lamin2 the disposition of the muscular pulp into filaments1 placed parallel to each other2 the investment of the filaments in membraneous sheaths2 the combination of the filaments1 included in their sheaths1 into fibres2 the aggregation of fibres into fasciculi2 and the analogous arrangement and combination of the nervous pulp1 are examples of structure4 ,but when those structures are applied to particular uses2 when they are so combined and disposed as to form a peculiar instrument1 endowed with a specific function2 when the cellular fibres1 for example1 are so arranged as to make a thin1 dense1 and expanded tissue2 when to this tissue are added blood-vessels1 absorbents1 and nerves2 when1 in a word1 a membrane is constructed1 an organ is formed2 when1 in like manner1 to the muscular and the nervous fibres1 arranged and moulded in the requisite mode1 are added blood-vessels1 absorbents1 and nerves1 other organs are constructed capable of performing specific functions3 and this is organization--the building up of organs--the combination of definite structures into special instruments4 ,structure is the preparatory process of organization2 the one is the mere arrangement of the material2 the other is the appropriation of the prepared material to a specific use4 #ec4 ,the term organization is employed in reference both to the component parts of the body1 and to the body considered as a whole4 ,we speak of an organized substance and of an organized body4 ,an organized substance is one in which there is not only a definite arrangement of its component parts 7structure71 but in which the particular arrangement is such as to fit it for accomplishing some special use4 ,every organized substance is therefore essentially a special organ2 limited in its object it may be1 and perhaps only conducive to some further object2 but still its distinctive character is1 that it has a peculiar structure1 fitting it for the accomplishment of some appropriate purpose4 ,on the other hand1 an organized body is a congeries of organs--the aggregate of the individual organs4 ,attention was directed in the early part of this work to one peculiar and essential character1 by which such an organized is distinguished from an unorganized body4 ,between the individual parts of the organized body there is so close a relation1 that no one of them can be removed or injured1 or in any manner affected without a corresponding affection of the whole4 ,the action of the heart cannot cease without the cessation of the action of the lung2 nor that of the lung without that of the brain2 nor that of the brain without that of the stomach2 in a word1 there is no organ in whatever distant nook of the system it be placed1 or however apparently insignificant its function1 that is not necessary to the perfection of the whole4 ,but into whatever number of portions an unorganized body may be divided1 each portion retains the properties of the mass1 and constitutes in itself a perfect existence2 there being no relation between its individual parts1 excepting that of physical attraction3 on the contrary1 each component part of an organized body1 being endowed with some appropriate and specific power1 on the exercise of which the powers of all the other parts are more or less dependent1 the whole must necessarily suffer if but one part fail4 #ed4 ,from the whole1 then1 we see that the human body is a congeries of organs2 that those organs are constructed of a few simple tissues2 and that all its parts1 numerous1 diversified1 and complex as they are1 are composed of but three primary forms of animal matter variously modified and combined4 ,illustration3 ,fig4 ,,xxxiii4 ,muscles of the back and shoulders2 showing their symmetrical disposition4 #ee4 ,but though by the analysis of its component parts1 this machine1 so complex in its construction1 and so wonderfully endowed1 may be reduced to this state of simplicity2 and although this analytical view of it be highly useful in enabling us to form a clear conception of the nature of its composition2 yet it is only by considering its individual parts such as they actually are1 and by studying their situation1 connexion1 structure1 and action1 that we can understand it as a whole1 and apply our knowledge of it to any practical use4 #ef4 ,viewing then the human body as a complicated whole1 as a congeries of organs made up of various combinations of simple tissues1 it may be observed1 in reference to its external configuration1 that it is rounded4 ,this rounded form is principally owing to the large proportion of fluids which enter into its composition4 ,the roundness of the face1 limbs1 and entire surface of the child1 are in striking contrast to the unequal and irregular surface of the old man1 whose humours are comparatively very much smaller in quantity4 #eg4 ,the length of the human body exceeds its breadth and thickness2 the degree of the excess varying at different periods of life1 and according to the peculiar constitution of the individual4 ,in the extremities1 the bones1 muscles1 vessels1 and nerves1 are especially distinguished by their length4 ,illustration3 ,fig4 ,,xxxiv4 ,front view of the skeleton4 #a4 the head2 #b4 the trunk2 #c4 the superior extremities2 #d4 the inferior extremities4 ,illustration3 ,fig4 ,,xxxv4 ,back view of the skeleton4 #a4 the head2 #b4 the trunk2 #c4 the superior extremities2 #d4 the inferior extremities4 #eh4 ,the form of the human body is symmetrical1 that is1 it is capable of being divided into two lateral and corresponding halves4 ,suppose a median line to pass from the vertex of the head through the centre of the spinal column 7fig4 ,,xxxiv4 #a1 #b72 if the body be well formed1 it will be divided by this line into two exactly equal and corresponding portions 7fig4 ,,xxxv4 #a74 ,this symmetrical disposition of the body is not confined to its external configuration4 ,it is true of many of the internal organs2 but principally1 as has been already stated1 of those that belong to the animal life4 ,the brain and the spinal cord are divisible into two exactly equal halves 7figs4 ,,xlviii4 d1 and ,,xlix4 #a1 #b1 #c72 the organs of sense are double and symmetrical3 the muscles of one side of the body exactly correspond to those of the other 7fig4 ,,xxxiii472 the two hands and arms and the two lower extremities are alike 7figs4 ,,xxxiv41 ,,xxxv472 but for the most part1 the organs of the organic life1 the stomach1 the intestines1 the liver1 the spleen1 for example1 are single1 and not symmetrical4 #ei4 ,the human body is divided into three great portions1 the head1 the trunk1 and the extremities 7figs4 ,,xxxiv4 and ,,xxxv4 #a1 #b1 #c1 #d74 #fj4 ,by the ,,head is meant all that part of the body which is placed above the first bone of the neck 7fig4 ,,xxxiv4 #a74 ,it is of a spheroidal figure1 broader and deeper behind than before1 somewhat like an egg in shape1 with the broad end behind2 it is flattened at its sides 7figs4 ,,xxxv4 #a1 and ,,xxxvi4 #b1 #d74 ,its peculiar figure renders it at once stronger and more capacious than it could have been had it possessed any other form4 ,it is supported by its base on the spinal column1 to which it is attached by the peculiar structure termed a joint 7fig4 ,,xxxiv471 and fastened by ligaments of exceeding strength4 #fa4 ,the head contains the central organ of the nervous system2 the organs of the senses1 with the exception of that of touch2 and the organs of mastication4 ,it comprehends the cranium and the face4 ,both are composed partly of soft parts1 as the teguments1 namely1 skin1 fat1 c41 and muscles2 and partly of bones4 ,illustration3 ,fig4 ,,xxxvi4 #a4 ,frontal bone2 #b4 parietal bone2 #c4 occipital bone2 #d4 temporal bone2 #e4 nasal bone2 #f4 malar bone2 #g4 superior maxillary bone2 #h4 inferior maxillary bone4 ,illustration3 ,fig4 ,,xxxvii4 ,bones of the skull1 separated2 front view4 #a4 ,frontal bone2 #b4 portions of the parietal bones2 #c4 malar or cheek bones2 #d4 nasal bones2 #e4 superior maxillary or bones of the upper jaw2 #f4 the vomer2 #g4 the inferior maxillary or bone of the lower jaw4 ,illustration3 ,fig4 ,,xxxviii4 ,bones of the skull separated2 side view4 #a4 ,frontal bone2 #b4 parietal bone2 #c4 occipital bone2 #d4 temporal bone2 #e4 nasal bone2 #f4 malar bone2 #g4 superior maxillary bone2 #h4 the unguis2 #i4 the inferior maxillary bone4 ,illustration3 ,fig4 ,,xxxix4 ,bones forming the base of the skull2 viewed from the inside4 #a4 ,occipital bone2 #b4 temporal bones2 #c4 sphenoid bone2 #d4 ethmoid bone2 #e4 superior maxillary bones1 or bones of the upper jaw2 #f4 malar or cheek bones2 #g4 foramen magnum4 #fb4 ,the bones of the cranium are eight in number1 six of which are proper to the cranium1 and two are common to it and to the face4 ,the six bones proper to the cranium are the frontal 7fig4 ,,xxxvii4 #a71 the two parietal 7fig4 ,,xxxvi4 #b71 the two temporal 7fig4 ,,xxxviii4 #d71 and the occipital 7fig4 ,,xxxviii4 #c72 the two common to the cranium and face are the ethmoidal 7fig4 ,,xxxix4 #d71 and the sphenoidal 7fig4 ,,xxxix4 #c74 ,the frontal bone forms the entire forepart of the vault 7fig4 ,,xxxvii4 #a72 the two parietal form the upper and middle part of it 7fig4 ,,xxxviii4 #b72 the two temporal form the lower part of the sides 7fig4 ,,xxxviii4 #d72 the occipital forms the whole hinder part1 together with a portion of the base 7figs4 ,,xxxviii4 #c1 ,,xxxvi4 #c1 ,,xxxix4 #a72 while the ethmoidal forms the forepart1 and the sphenoidal the middle part of the base 7fig4 ,,xxxix4 #c1 #d74 ,illustration3 ,fig4 ,,xl4 #b #a ,portions of the bones of the cranium2 showing the corresponding inequalities in their margins3 which margins1 when in apposition1 constitute the mode of union termed suture4 #a4 ,external surface of the bone2 #b4 internal surface4 ,illustration3 ,fig4 ,,xli4 #a ,fig4 ,,xlii4 #b #a4 ,side view of the adult skull1 showing the several bones united by suture2 #b4 side view of the ftal skull1 showing the bones imperfectly ossified1 separated to some extent from each other1 the interspace being occupied by membrane4 ,the small size of the face compared with that of the cranium is strikingly apparent4 #fc4 ,these bones are firmly united together4 ,the union of bones is technically called an articulation or joint4 ,all joints are either immoveable or moveable4 ,the union of the bones of the cranium affords an example of an immoveable articulation4 ,prominences and indentations1 like the teeth of a saw1 are formed in the margins of the contiguous bones 7figs4 ,,xxxviii4 and ,,xl474 ,at these inequalities of surface1 which are exactly adapted to each other 7figs4 ,,xxxviii4 and ,,xl471 the two bones are in immediate apposition in such a manner as to preclude the possibility of motion1 and even to render the separation extremely difficult4 ,this mode of articulation is termed a suture4 ,there are certain advantages in constructing the cranium of several distinct bones1 and in uniting them in this peculiar mode4 #a4 ,the walls of the vault are stronger than they could have been had they been formed of a single piece4 #b4 ,in the ftus1 the bones are at some distance from each other 7fig4 ,,xlii472 at birth1 they yield and overlap one another2 and in this manner they conduce to the security and ease of that event4 #c4 ,minute vessels pass abundantly and securely through the interstices of the sutures to and from the interior of the cranium2 in this manner1 a free communication is established between the vessels within and without this cavity4 #d4 ,it is probable that the shock produced by external violence is diminished in consequence of the interruption of the vibration occasioned by the suture2 it is certain that fracture is prevented by it from extending as far as it would do in one continued bony substance4 ,illustration3 ,fig4 ,,xliii4 ,section of the skull4 #a4 ,cavity of the cranium occupied by the brain2 #b4 cut edge of the bones of the cranium1 showing the two tables of compact bone and the intervening spongy texture called diplo4 #fd4 ,the vault of the cranium forms a cavity which contains the brain 7fig4 ,,xliii4 and ,,xlviii47 ,the size of this cavity is invariably proportioned to that of the organ it lodges and protects4 ,the form and magnitude of the cavity1 and consequently the shape and size of the cranium1 depend upon the brain1 and not of the brain upon the cranium4 ,the soft parts model and adapt to themselves the hard1 and not the hard the soft4 ,the formation of the brain in the ftus is anterior to that of the case which ultimately contains it2 and the hard bone is moulded upon the soft pulp1 not the pulp upon the bone4 ,at every period of life1 on the inner surface of the cranium there are visible impressions made by the convolutions of the brain1 and the ramifications of the arteries 7figs4 ,,xxxix4 #a1 #b1 and ,,xl4 #b71 and on its external surface are depressions occasioned by the action of the external muscles4 ,nor does the modifying power of the brain over the bones of the cranium terminate at birth4 ,the formation of bone1 always a slow process1 is never completed until the child has attained its third or fourth year1 and often not until a much later period4 ,at this tender age1 the bones1 which in advanced life are hard and rigid1 are comparatively soft and yielding1 and consequently more readily receive and retain the impression of the convolutions and of the other projecting parts of the brain1 by which they are sometimes so deeply marked1 that an attentive examination of the inner surface of the cranium is of itself sufficient to determine not only that some part1 but to indicate the very part of the brain which has been preternaturally active4 ,at this tender age1 pressure1 internal or external1 general or partial1 may readily change the form of the cranium4 ,if1 by a particular posture1 the head of a child be unequally balanced on the spine1 the brain will press more on that side of the cranium than on the other2 the organ will expand in the direction to which it inclines2 that portion of it will become preternaturally developed1 and consequently the balance of its functions will be disturbed4 ,an awkward way of standing or sitting1 perhaps contracted inadvertently and kept up by habit2 a wry neck2 any cause that keeps the head constantly inclined to one side1 may produce this result1 examples of which and of its consequences will be given hereafter4 #fe4 ,tracing them from without inwards we see1 then1 that the various coverings afforded to the brain1 the central organ of the animal life1 seated in its vaulted cavity1 are3 #a4 ,the tegument1 consisting of the skin and of cellular and adipose membrane4 #b4 ,beneath the tegument1 muscles1 in the forepart and at the vertex1 comparatively slender and delicate2 at the sides and posteriorly1 thick1 strong1 and powerful 7fig4 ,,xliv474 #c4 ,beneath the muscles1 a thin but dense membrane1 termed the pericranium1 lining the external surface of the cranial bones4 #d4 ,beneath the pericranium1 the bony substance of the cranium1 consisting of two firm and hard bony plates1 with a spongy1 bony structure1 called diplo1 interposed between them 7fig4 ,,xliii4 #b74 #e4 ,immediately in contact with the inner surface of the bony substance of the cranium1 and forming its internal lining1 the dense and strong membrane1 called the dura mater1 not only affording a general covering to the brain1 but sending firm partitions between individual portions of it 7fig4 ,,xlviii4 c474 #f4 ,a serous membrane lining the internal surface of the dura mater1 and reflected over the entire surface of the brain1 termed the arachnoid tunic4 #g4 ,a thin and delicate membrane in immediate contact with the substance of the brain1 descending between all its convolutions1 lining all its cavities and enveloping all its fibres1 called the pia mater4 #h4 ,an aqueous fluid1 contained between the arachnoid membrane and the pia mater4 ,skin1 muscle1 pericranium1 bone1 dura mater1 arachnoid membrane1 pia mater1 and aqueous fluid1 superimposed one upon another1 form1 then1 the covering and defence of the brain2 so great is the care taken to protect this soft and tender substance4 #ff4 ,the bones of the face consist of fourteen1 namely1 the two superior maxillary or jaw-bones 7fig4 ,,xxxvii4 #e71 the two malar or cheek bones 7fig4 ,,xxxvii4 #c71 the two nasal bones 7fig4 ,,xxxvii4 #d71 the two palate bones1 the two ossa unguis 7fig4 ,,xxxviii4 #h71 the two inferior turbinated bones1 the vomer 7fig4 ,,xxxvii4 #f71 and the inferior maxilla or the lower jaw 7fig4 ,,xxxvii4 #g47 ,this irregular pile of bones is divided into the superior and inferior maxilla or jaws2 the superior maxilla being the upper and immoveable portion of the face2 the inferior maxilla being the lower and moveable portion of it4 ,besides these bones1 the face contains thirty-two teeth1 sixteen in each jaw4 ,the bones of the upper jaw are united together by sutures1 and the union is so firm1 that they have no motion but what they possess in common with the cranium4 ,the lower jaw is united by a distinct articulation with the cranium 7figs4 ,,xxxiv4 and ,,xxxv474 #fg4 ,besides the bones and the teguments1 the face contains a number of muscles1 which for the most part are small and delicate 7fig4 ,,xliv471 together with a considerable portion of adipose matter2 while1 as has been stated1 the face and head together contain all the senses1 with the exception of that of touch1 which is diffused1 more or less1 over the entire surface of the body4 ,illustration3 ,fig4 ,,xliv4 ,muscles of the face4 #fh4 ,the second great division of the body1 termed the ,,trunk1 extends from the first bone of the neck to that called the pubis in front1 and to the lower end of the coccyx behind 7fig4 ,,xxxiv4 #b74 ,it is subdivided into the thorax1 the abdomen1 and the pelvis 7fig4 ,,xlv474 #fi4 ,the thorax or chest extends above from the first bone of the neck1 by which it is connected with the head1 to the diaphragm below1 by which it is divided from the abdomen 7figs4 ,,xlv4 and ,,lxi474 ,it consists partly of muscles and partly of bones2 the muscular and the osseous portions being in nearly equal proportions4 ,both together form the walls of a cavity in which are placed the central organs of circulation and respiration 7fig4 ,,lx4 #b1 #e74 ,the chief boundaries of the cavity of the thorax before1 behind1 and at the sides1 are osseous 7fig4 ,,xlv472 being formed before1 by the sternum or breast-bone 7fig4 ,,xlv4 #f72 behind1 by the spinal column or back bone 7fig4 ,,xlv4 #b1 #d72 and at the sides1 by the ribs 7fig4 ,,xlv4 #g74 ,below1 the boundary is muscular1 being formed by the diaphragm 7fig4 ,,lxi4 #b71 while above the thorax is so much contracted 7fig4 ,,xlv471 that there is merely a space left for the passage of certain parts which will be noticed immediately4 #gj4 ,the figure of the thorax is that of a cone1 the apex being above 7fig4 ,,xlv471 through the aperture of which pass the tubes that lead to the lungs and stomach1 and the great blood-vessels that go to and from the heart 7fig4 ,,lx474 ,the base of the cone is slanting1 and is considerably shorter before than behind1 like an oblique section of the cone 7fig4 ,,xlv474 #ga4 ,the osseous portion of the walls of the thorax is formed behind by the spinal column1 a range of bones common indeed to all the divisions of the trunk2 for it constitutes alike the posterior boundary of the thorax1 abdomen1 and pelvis 7fig4 ,,xlv4 #b1 #d1 #f74 ,it is composed of thirty distinct bones1 twenty-four of which are separate and moveable on one another1 and on this account are called true vertebr 7fig4 ,,xlv4 #b1 #d72 the other five1 though separate at an early period of life1 are subsequently united into a single solid piece1 called the sacrum 7fig4 ,,xlv4 #e74 ,the bones composing this solid piece1 as they admit of no motion on each other1 are called false vertebr 7fig4 ,,xlv4 #e74 ,to the extremity of the sacrum is attached the last bone of the series1 termed the coccyx 7fig4 ,,xxxv474 #gb4 ,from above downwards1 that is1 from the first bone of the neck to the first bone of the sacrum1 the separate bones forming the column progressively increase in size2 for this column is the chief support of the weight of the head and trunk1 and this weight is progressively augmenting to this point 7fig4 ,,xlv4 #b1 #d74 ,from the sacrum to the coccyx1 the bones successively diminish in size1 until1 at the extremity of the coccyx1 they come to a point 7fig4 ,,xxxv474 ,the spinal column may therefore be said to consist of two pyramids united at their base 7fig4 ,,xlv4 #d1 #e74 ,the superior pyramid is equal in length to about one third of the height of the body1 and it is this portion of the column only that is moveable4 #gc4 ,the two surfaces of the spinal column1 the anterior and the posterior1 present a striking contrast 7figs4 ,,xxxiv4 and ,,xxxv474 ,the anterior surface1 which in its whole extent is rounded and smooth1 is broad in the region of the neck1 narrow in the region of the back1 and again broad in the region of the loins 7fig4 ,,xlv4 #b1 #d474 ,it presents three curvatures 7fig4 ,,xlv4 #b1 #d72 the convexity of that of the neck being forwards1 that of the back backwards1 and that of the loins again forwards 7fig4 ,,xlv4 #b1 #d74 #gd4 ,from the posterior surface of the column1 which is every where irregular and rough1 spring1 along the median line1 in regular series1 strong1 sharp1 and pointed projections of bone 7fig4 ,,xxxv471 which from being sharp and pointed1 like elongated spines1 are called spinous processes1 and have given name to the whole chain of bones4 ,these processes afford fixed points for the action of powerful muscles4 ,extending the whole length of the column1 from the base of the skull to the sacrum1 on each side of the spinous processes1 are deep excavations1 which are filled up with the powerful muscles that maintain the trunk of the body erect4 #ge4 ,from the lateral surfaces of the column likewise spring short but strong projections of bone1 termed transverse processes1 which also give attachment to powerful muscles 7fig4 ,,xlvi474 ,illustration3 ,fig4 ,,xlv4 ,bones of the trunk4 #a4 ,spinal column2 #b4 the seven cervical vertebr2 #c4 the twelve dorsal vertebr2 #d4 the five lumbar vertebr2 #e4 the sacrum2 #f4 the sternum2 #g4 the true ribs2 #h4 the false ribs2 #i4 the clavicle2 #aj4 the scapula2 #aa4 the ilium2 #ab4 the ischium2 #ac4 the pubes2 #ad4 the acetabulum2 #ae4 the brim of the pelvis4 #gf4 ,the separate bones of the series have a kind of turning motion on each other2 hence each is called a vertebra1 and the name of vertebral column is often given to the entire series1 as well as that of spinal column4 ,that portion of the column which forms the neck consists of seven distinct bones1 called cervical vertebr 7fig4 ,,xlv4 #b72 that portion which forms the back consists of twelve1 called dorsal vertebr 7fig4 ,,xlv4 #c72 that portion which forms the loins consists of five1 called lumbar vertebr 7fig4 ,,xlv4 #d74 ,between each of these classes of vertebr there are specific differences1 but they need not be described here3 all that is necessary to the present purpose is an account of the structure which is common to every vertebra4 #gg4 ,by inspecting fig4 ,,xlvi4 #a1 it will be seen that the upper and under edges of each vertebra consist of a ring of bone1 of a firm and compact texture1 rendering what may be called the body of the vertebra exceedingly strong 7fig4 ,,xlvi4 #c74 ,this ring of bone forms a superficial depression 7fig4 ,,xlvi4 #b71 for the reception of a peculiar substance1 immediately to be described1 which is interposed between each vertebra 7fig4 ,,xlvii4 #b74 #gh4 ,the anterior surface of the body of the vertebra is convex 7fig4 ,,xlvi4 #c72 its posterior surface is concave 7fig4 ,,xlvi4 #d72 from the posterior surface springs a bony arch 7figs4 ,,xlvi4 #e and ,,liii4 #a71 which1 together with the posterior concavity1 forms an aperture of considerable magnitude 7fig4 ,,xlvi4 #f71 a portion of the canal for the passage of the spinal cord 7figs4 ,,xlvii4 #c1 and ,,xlix4 #c74 ,illustration3 ,fig4 ,,xlvi4 ,view of some of the vertebr1 which by their union form the spinal column4 a4 ,a vertebra of the neck2 b4 a vertebra of the back2 a vertebra of the loins4 #a4 ,ring of compact bone forming1 #c1 the body of the vertebra2 #b4 superficial depression for the reception of the intervertebral cartilage2 #c4 anterior surface of the body of the vertebra2 #d4 posterior surface2 #e4 bony arch2 #f4 opening for the passage of the spinal cord2 #g4 opening for the passage of the spinal nerves2 #h4 articulating processes by which the vertebr are joined to each other2 #i4 two dorsal vertebr united1 showing the arrangement of1 #aj1 the spinous processes2 #aa4 a portion of a rib articulated with the side of the vertebra4 #gi4 ,both the upper and under edges of the arch form a notch 7fig4 ,,xlvi4 #g471 which1 together with a corresponding notch in the contiguous vertebra1 completes another aperture rounder and smaller than the former1 but still of considerable size 7fig4 ,,xlvi4 #g471 the passage of the spinal nerves 7fig4 ,,xlvii4 #c74 #hj4 ,from both the upper and under sides of the arch proceed two short but strong projections of bone 7fig4 ,,xlvi4 #h471 termed the articulating processes1 because it is chiefly by these processes that the vertebr are connected together4 ,from the beginning to the end of the series1 the two upper processes of the one vertebra are united with the two lower processes of the vertebra immediately above it 7fig4 ,,xlvi4 #i71 and around the edges of all the articulating processes are visible rough lines1 which mark the places to which the articulating ligaments are attached4 #ha4 ,no vertebra1 except the first1 rests immediately upon its contiguous vertebra 7fig4 ,,xlv4 #b1 #d74 ,each is separated from its fellow by a substance of a peculiar nature interposed between them1 termed the intervertebral substance 7figs4 ,,xlvii4 #b1 and ,l4 #b74 ,this substance partakes partly of the nature of cartilage1 and partly of that of ligament4 ,it is composed of concentric plates1 formed of oblique fibres which intersect each other in every direction4 ,this substance1 for about a quarter of an inch from its circumference towards its centre1 is tough1 strong1 and unyielding2 then it becomes softer1 and is manifestly elastic2 and so it continues until it approaches the centre1 when it becomes pulpy1 and is again inelastic4 ,the exterior tough and unyielding matter is for the firmness of the connexion of the several vertebr with each other2 the interior softer and elastic matter is for the easy play of the vertebr upon each other2 the one for security1 the other for pliancy4 ,and the adjustment of the one to the other is such as to combine these properties in a perfect1 manner4 ,the quantity of the unyielding substance is not so great as to produce rigidity2 the quantity of the elastic substance is not so great as to occasion insecurity4 ,the firm union of its solid matter renders the entire column strong2 the aggregate elasticity of its softer substance renders it springy4 ,illustration3 ,fig4 ,,xlvii4 #a4 ,one of the ,lumbar vertebr4 #b4 ,intervertebral substance4 #c4 ,a portion of the spinal cord in its canal4 #hb4 ,the column is not constructed in such a manner as to admit of an equal degree of motion in every part of it4 ,every thing is contrived to give to that portion which belongs to the neck freedom of motion1 and1 on the contrary1 to render that portion which belongs to the back comparatively fixed4 ,in the neck the mechanism of the articulating processes is such as to admit of an equal degree of sliding motion forwards1 backwards1 and from side to side1 together with a turning motion of one bone upon another2 at the same time1 the intervertebral substance between the several vertebr is thick4 ,in consequence of this mechanism1 we can touch the breast with the chin1 the back with the hind head1 and the shoulders with the ear1 while we can make the head describe more than a semicircle4 ,but1 in the back1 the articulating processes are so connected as to prevent the possibility of any motion1 either forwards or backwards1 or any turning of one vertebra upon another1 while the intervertebral substance is comparatively thin 7fig4 ,,xlv4 #b1 #d74 ,that portion of the column which belongs to the back is intended to afford a fixed support for the ribs1 a support which is indispensable to their action in the function of respiration4 ,in the loins1 the articulating processes are so connected as to admit of a considerable degree of motion in the horizontal direction1 and from side to side1 and the intervertebral substance here progressively increases in thickness to the point at which the upper portion of the column is united to the sacrum 7fig4 ,,xlv4 #b1 #d71 where the degree of motion is extensive4 #hc4 ,the canal for the spinal cord1 formed partly by the concavity in the posterior surface of the vertebra1 and partly by the arch that springs from it 7fig4 ,,xlvi4 #f471 is lined by a continuation of the dense and strong membrane that constitutes the internal periosteum of the cranium1 the dura mater 7fig4 ,,xlviii4 c71 which1 passing out of the opening in the occipital bone1 called the foramen magnum 7figs4 ,,xxxix4 #g1 and ,,xlix4 #c71 affords a smooth covering to the canal throughout its whole extent4 ,illustration3 ,fig4 ,,xlviii4 a4 ,the scalp1 turned down4 b4 ,the cut edge of the bones of the skull4 c4 ,the external strong membrane of the brain 7,dura ,mater7 suspended by a hook4 d4 ,the left hemisphere of the brain1 showing its convolutions4 e4 ,the superior edge of the right hemisphere4 f4 ,the fissure between the two hemispheres4 ,illustration3 ,fig4 ,,xlix4 #a4 ,hemispheres of the brain proper1 or cerebrum2 #b4 hemispheres of the smaller brain1 or cerebellum2 #c4 spinal cord continuous with the brain1 and the spinal nerves proceeding from it on each side4 #hd4 ,the spinal cord itself1 continuous with the substance of the brain1 passes also out of the cranium through the foramen magnum into the spinal canal 7fig4 ,,xlix4 #c71 enveloped in the delicate membranes that cover it1 and surrounded by the aqueous fluid contained between those membranes4 ,the size of the spinal canal1 accurately adapted to that of the spinal cord1 which it lodges and protects1 is of considerable size1 and of a triangular shape in its cervical portion 7fig4 ,,xlix4 #c71 smaller and rounded in its dorsal portion 7fig4 ,,xlix4 #c71 and again large and triangular in its lumbar portion 7fig4 ,,xlix4 #c74 #he4 ,the spinal column performs several different1 and apparently incompatible1 offices4 ,first1 it affords a support and buttress to other bones4 ,it sustains the head 7fig4 ,,xxxiv4 #a72 it is a buttress to the ribs 7fig4 ,,xlvi4 #g72 through the sternum and ribs it is also a buttress to the superior1 and through the pelvis1 to the lower1 extremities 7fig4 ,,xxxiv4 #b1 #c1 #d74 ,secondly1 it affords a support to powerful muscles1 partly to those that maintain the trunk of the body in the erect posture against the force of gravitation1 and partly to those that act upon the superior and inferior extremities in the varied1 energetic1 and sometimes long-continued movements they execute4 ,thirdly1 it forms one of the boundaries of the great cavities that contain the chief organs of the organic life4 ,to the support and protection of those organs it is specially adapted2 hence the surface in immediate contact with them is even and smooth2 hence its different curvatures1 convexities1 and concavities1 have all reference to their accommodation2 hence in the neck it is convex 7fig4 ,,xlv4 #b71 in order to afford a firm support to the esophagus1 the wind-pipe1 the aorta1 and the great trunks of the venous system 7fig4 ,,lx4 #c1 #d72 in the back it is concave1 in order to enlarge the space for the dilatation of the lung in the act of inspiration 7figs4 ,,xlv4 #c1 and ,,lx4 #e72 in the loins it is convex1 in order to sustain and fix the loose and floating viscera of the abdomen 7figs4 ,,xlv4 #d1 and ,,lx4 #f1 #g1 #h1 #i72 in the pelvis it is concave1 in order to enlarge the space for lodging the numerous delicate and highly-important organs contained in that cavity 7fig4 ,,xlv4 #e74 ,fourthly1 it forms the osseous walls of a canal 7figs4 ,,xlvi4 #f1 and ,,xlvii4 #c7 for the lodgment and protection of the soft and tender substance of the spinal cord1 one of the great central masses of the nervous system1 the seat of the animal life 7fig4 ,,xlix4 #c74 ,fifthly1 it affords in its osseous walls secure apertures for the passage of the spinal nerves 7figs4 ,,xlvi4 #g1 and ,,xlix4 #c71 by which impressions are transmitted from the organs to the spinal cord and brain1 in the function of sensation2 and from the spinal cord and brain to the organs in the function of volition4 #hf4 ,for the due performance of these offices1 it is indispensable that it should be firm1 rigid1 strong1 and yet to a certain extent readily flexible in every direction4 ,by what mechanism is it endowed with these apparently incompatible properties8 #hg4 ,by means of the ring of compact bone1 which forms so large a part of its body 7fig4 ,,xlvi4 #a7 it is rendered firm1 rigid1 and strong4 ,by means of its numerous separate pieces1 exactly adjusted to each other1 and dove-tailed into one another1 an increase of strength is gained1 such as it would not have been possible to communicate to a single solid piece4 ,by the same mechanism1 some degree of flexibility is also obtained2 each separate bone yielding to some extent1 which1 though slight in a single bone1 becomes considerable in the twenty-four4 #hh4 ,but the flexibility required is much greater than could be obtained by this expedient alone4 ,a rigid and immoveable pile of bones1 in the position of the spinal column1 on which all the other parts of the body rest1 and to which they are directly or indirectly attached1 would necessarily have rendered all its movements stiff and mechanical2 and every movement of every kind impossible1 but in a given direction4 ,that the movements of the body may be easy1 free1 and varied2 that it may be possible to bring into play new and complex combinations of motion at any instant1 with the rapidity of the changes of thought1 at the command of the impulses of feeling1 it is indispensable that the spinal column be flexible in every direction1 forwards1 backwards1 and at the sides3 it is equally indispensable that it be thus capable of yielding1 without injuring the spinal cord2 without injuring the spinal nerves2 without injuring the thoracic and abdominal viscera2 and without injuring the muscles of the trunk and extremities4 ,the degree in which it possesses this power of flexibility1 and the extent to which1 by the cultivation of it1 it is sometimes actually brought1 is exemplified in the positions and contortions of the posture-master and the tumbler4 ,it is acquired by means of the intervertebral substance1 the compressible and elastic matter interposed between the several vertebr4 ,so compressible is this substance1 that the human body is half an inch shorter in the evening than in the morning1 having lost by the exertions of the day so much of its stature2 yet1 so elastic is this matter1 that the stature lost during the day is regained by the repose of the night4 ,the weight of the body pressing in all directions upon the spinal column2 muscles1 bones1 cartilages1 ligaments1 membranes1 with all their vessels and all the fluids contained in them2 the weight of all these component parts of the head1 trunk1 and extremities1 pressing1 without the cessation of an instant1 during all the hours of vigilance1 upon the intervertebral substance1 compresses it2 but this weight1 being taken off during the night1 by the recumbent posture of the body1 the intervertebral substance1 in consequence of its elasticity1 regains its original bulk1 and of course the spinal column its original length4 #hi4 ,but the flexibility acquired through the combined properties of compressibility and elasticity is exceedingly increased by the action of the pulpy and inelastic matter in the centre of the intervertebral substance2 this matter serving as a pivot to the vertebr1 facilitating their motion on each other4 ,its effect has been compared to that of a bladder partly filled with water1 placed between two trenchers2 in this case1 the approximation of the circumference of the two trenchers on one side1 would instantly displace a portion of the water on that side1 which would occupy the increasing space on the other1 with the effect of facilitating the change1 in every possible direction1 of the position of the two trenchers in relation to each other4 ,to this effect1 however1 it is indispensable that the matter immediately around this central pivot should be1 not like itself1 rigid and unyielding1 but compressible and elastic4 ,it is an interesting fact1 that since this illustration was suggested1 it has been discovered that this very arrangement is actually adopted in the animal body4 ,in certain animals1 in the very centre of their intervertebral substance1 there has been actually found a bag of water1 with a substance immediately surrounding the bag1 so exceedingly elastic1 that when the bag is cut1 the fluid contained in it is projected to the height of several feet in a perpendicular stream4 #ij4 ,but besides securing freedom and extent of motion1 the intervertebral substance serves still another purpose1 which well deserves attention4 ,firmness and strength are indispensable to the fundamental offices performed by the column2 and to endow it with these properties1 we have seen that the external concentric layers of the intervertebral substance are exceedingly tough and that they are attached to the bodies of the vertebr1 which are composed of dense and compact bone4 ,but than dense and compact bone1 nothing can be conceived better calculated to receive and transmit a shock or jar on the application of any degree of force to the column4 ,yet such force must necessarily be applied to it in every direction1 from many points of the body1 during almost every moment of the day2 and did it actually produce a corresponding shock1 the consequence would be fatal3 the spinal cord and brain would be inevitably killed2 for the death of these tender and delicate substances may be produced by a violent jar1 although not a particle of the substances themselves be touched4 ,a blow on the head may destroy life instantaneously1 by what is termed concussion2 that is1 by the communication of a shock to the brain through the bones of the cranium4 ,the brain is killed2 but on careful examination of the cerebral substance after death1 not the slightest morbid appearance can be detected3 death is occasioned merely by the jar4 ,a special provision is made against this evil1 in the structure of the bones of the cranium1 by the interposition between its two compact plates of the spongy substance called diplo 7fig4 ,,xliii4 #b72 and this is sufficient to prevent mischief in ordinary cases4 ,a great degree of violence applied directly to the head is not common3 when it occurs it is accidental3 thousands of people pass through life without ever having suffered from it on a single occasion3 but every hour1 in the ordinary movements of the body1 and much more in the violent movements which it occasionally makes1 a degree of force is applied to the spinal column1 and through it transmitted to the head1 such as1 did it produce a proportionate shock1 would inevitably and instantly destroy both spinal cord and brain4 ,the evil is obviated partly by the elastic1 and partly by the non elastic properties of the matter interposed between the several layers of compact bone4 ,by means of the elastic property of this matter1 the head rides upon the summit of the column as upon a pliant spring1 while the canal of the spinal cord remains secure and uninvaded4 ,by means of the soft and pulpy portion of this matter1 the vibrations excited in the compact bone are absorbed point by point as they are produced3 as many layers of this soft and pulpy substance1 so many points of absorption of the tremors excited in the compact bone2 so many barriers against the possibility of the transmission of a shock to the delicate nervous substance4 #ia4 ,alike admirable is the mechanism by which the separate pieces of the column are joined together4 ,if but one of the bones were to slip off its corresponding bone1 or to be displaced in any degree1 incurable paralysis1 followed ultimately by death1 or instantaneous death1 would happen2 for pressure on the spinal cord in a certain part of its course is incompatible with the power of voluntary motion1 and with the continuance of life for any protracted term2 and in another part of its course1 with the maintenance of life beyond a few moments4 ,to prevent such consequences1 so great is the strength1 so perfect the attachment1 so unconquerable the resistance of that portion of the intervertebral substance which surrounds the edge of the bodies of the vertebr1 that it will allow the bone itself to give way rather than yield4 ,yet such is the importance of security to this portion of the frame1 that it is not trusted to one expedient alone1 adequate as that might seem4 ,besides the intervertebral substance1 there is another distinct provision for the articulation of the bodies of the vertebr4 ,commencing at the second cervical vertebra1 in its fore part1 and extending the whole length of the column to the sacrum1 is a powerful ligament1 composed of numerous distinct longitudinal fibres 7fig4 ,l471 which are particularly expanded over the intervals between the bones occupied by the intervertebral substance 7figs4 ,l4 #a1 and ,,li4 #b1 #b74 ,this ligament is termed the common anterior vertebral1 beneath which1 if it be raised from the intervertebral substance1 may be seen small decussating fibres1 passing from the lower edge of the vertebra above1 to the upper edge of the vertebra below 7fig4 ,l4 #c71 from which circumstance these fibres are termed crucial4 ,illustration3 ,fig4 ,l4 #a4 ,common anterior ligament2 #b4 intervertebral substance4 ,the anterior ligament is removed to exhibit 7#c47 the crucial fibres passing over it4 ,illustration3 ,fig4 ,,li4 #a4 ,portion of the occipital bone2 #b4 common anterior ligament4 #ib4 ,corresponding with the ligament on the anterior1 is another on the posterior part of the spine 7fig4 ,,lii4 #a71 which takes its origin from the foramen magnum 7fig4 ,,lii4 #a72 descends from thence1 within the vertebral canal1 on the posterior surface of the bodies of the vertebra 7fig4 ,,lii4 #a71 and extends to the sacrum4 ,this ligament is termed the common posterior vertebral1 which1 besides adding to the strength of the union of the bodies of the vertebr1 prevents the column itself from being bent too much forward4 ,illustration3 ,fig4 ,,lii4 #a4 ,posterior vertebral ligament4 #ic4 ,moreover1 the bony arches of the vertebr 7fig4 ,,liii4 #a7 are connected by means of a substance partly ligamentous1 and partly cartilaginous 7fig4 ,,liii4 #b71 which1 while it is extremely elastic1 is capable of resisting an extraordinary degree of force4 ,illustration3 ,fig4 ,,liii4 #a4 ,arches of the vertebr seen from within2 #b4 ligaments connecting them4 #id4 ,and in the last place1 the articular processes form so many distinct joints1 each being furnished with all the apparatus of a moveable joint1 and thus possessing the ordinary provision for the articulation of bones1 in addition to the whole of the foregoing securities4 #ie4 ,in the most extensive motion of which the spinal column is capable1 that of flexion1 the common anterior ligament is relaxed2 the fore part of the intervertebral substance is compressed1 and its back part stretched2 while the common posterior ligament is in a state of extension4 ,in the extension of the column the state of the ligaments is reversed2 those which were extended being in their turn relaxed1 while the common anterior vertebral is now put upon the stretch4 ,in the lateral inclination of the column1 the intervertebral substance is compressed on that side to which the body is bent4 ,in the rotatory motion of the column1 which is very limited in all the vertebr1 but more particularly in the dorsal1 in consequence of their attachment to the ribs1 the intervertebral substance is contorted1 as are likewise all the ligaments4 ,all the motions of the column are capable of being aided to a great extent by the motion of the pelvis upon the thighs4 #if4 ,the number and breadth of the attachments of these bones1 says an accomplished anatomist and surgeon1#d their firm union by ligament1 the strength of their muscles1 the very inconsiderable degree of motion which exists between any two of them1 and lastly1 the obliquity of their articular processes1 especially in the dorsal and lumbar vertebr1 render dislocation of them1 at least in those regions1 impossible without fracture2 and ,i much doubt whether dislocation even of the cervical vertebr ever occurs without fracture1 either through their bodies or their articular processes4 ,the effects of each of these accidents would produce precisely the same injury to the spinal marrow1 and symptoms of greater or less importance1 according to the part of the spinal column that is injured4 ,death is the immediate consequence if the injury be above the third cervical vertebra1 the necessary paralysis of the parts to which the phrenic and intercostal nerves are distributed causing respiration instantly to cease4 ,if the injury be sustained below the fourth cervical vertebra1 the diaphragm is still capable of action1 and dissolution is protracted4 ,the symptoms1 in fact1 are less violent in proportion as the injury to the spinal marrow is further removed from the brain2 but death is the inevitable consequence1 and that in every case at no very distant period4 #ig4 ,so the object of the construction of the spinal column being to combine extent and freedom of motion with strength1 and it being necessary to the accomplishment of this object to build up the column of separate pieces of bone1 the connecting substances by which the different bones are united are constituted and disposed in such a manner as to prove absolutely stronger than the bones themselves4 ,such is the structure of this important portion of the human body considered as a piece of mere mechanism2 but our conception of its beauty and perfection would be most inadequate if we did not bear in mind1 that while the spinal column performs offices so varied and apparently so incompatible1 it forms an integrant portion of a living machine3 it is itself alive3 every instant1 blood-vessels1 absorbents and nerves1 are nourishing1 removing1 renewing1 and animating every part and particle of it4 #ih4 ,the anterior boundary of the thorax is formed by the bone called the sternum1 or the breast-bone1 which is broad and thick at its upper1 and thin and elongated at its lower extremity 7figs4 ,,xlv4 #f1 and ,,liv471 where it gives attachment to a cartilaginous appendix1 which being pointed and somewhat like a broadsword1 is called the ensiform cartilage4 ,illustration3 ,fig4 ,,liv4 ,anterior view of the sternum4 #ii4 ,its position is oblique1 being near the vertebral column at the top1 and distant from it at the bottom 7fig4 ,,xlv4 #f74 ,its margins are thick1 and marked by seven depressions1 for the reception of the cartilages of the seven true ribs 7fig4 ,,liv74 ,its anterior surface is immediately subjacent to the skin1 and gives attachment to powerful muscles1 which act on the superior extremities3 its posterior surface is slightly hollowed in order to enlarge the cavity of the thorax 7fig4 ,,lv474 ,illustration3 ,fig4 ,,lv4 ,posterior view of the sternum4 #ajj4 ,the thorax is bounded at the sides by the ribs1 which extend like so many arches between the spinal column and the sternum 7fig4 ,,xlv4 #g1 #h74 ,they are in number twenty-four1 twelve on each side1 of which the seven upper are united to the sternum by cartilage1 and are called true ribs 7fig4 ,,xlv4 #g72 the cartilages of the remaining five are united with each other and are not attached to the sternum2 these are called false ribs 7fig4 ,,xlv4 #h73 all of them are connected behind to the spinal column 7fig4 ,,xxxv474 #aja4 ,the ribs successively and considerably increase in length as far as the seventh1 by which the cavity they encompass is enlarged2 from the seventh they successively diminish in length1 and the capacity of the corresponding part of the cavity is lessened4 ,the direction of the ribs from above downwards is oblique 7fig4 ,,xlv4 #g1 #h74 ,their external or anterior surface is convex 7fig4 ,,xlv4 #g1 #h72 their internal or posterior surface is concave3 by the first their strength is increased2 by the second the general cavity of the thorax is enlarged 7fig4 ,,xlv4 #g1 #h74 ,their upper margin is smooth and rounded1 and gives attachment to a double layer of muscles1 called the intercostal1 placed in the intervals that separate the ribs from each other 7fig4 ,,lix474 ,along the lower margin is excavated a deep groove1 for the lodgment and protection of the intercostal vessels4 #ajb4 ,the ribs are connected with the spinal column chiefly by what is termed the anterior ligament 7fig4 ,,lvi4 #a71 which is attached to the head of the rib 7fig4 ,,lvi471 and which1 dividing into three portions 7fig4 ,,lvi4 #a71 firmly unites every rib to two of the vertebr1 and to the intervertebral substance 7fig4 ,,lvi4 #a74 ,this articulation is fortified by a second ligament 7fig4 ,,lvi4 #b71 also attached to a head of the rib1 termed the interarticular 7fig4 ,,lvi4 #b71 and by three others1 one of which is attached on the fore part1 and the two others in the back part1 to the neck of the rib 7fig4 ,,lvii4 #a74 ,illustration3 ,fig4 ,,lvi4 ,ligaments connecting the ribs to the spinal column4 #a4 anterior ligaments2 #b4 interarticular ligament2 #c4 ligaments of the necks of the ribs4 ,the cartilages of the seven superior ribs are attached to the sternum by a double layer of ligamentous fibres1 termed the anterior and the posterior ligaments of the sternum 7fig4 ,,lviii474 ,so strong are the bands which thus attach the ribs to the spinal column and the sternum1 that the ribs cannot be dislocated without fracture4 ,such at least is the case in experiments upon the dead body1 where1 though the rib be subjected to the application of force by means of an instrument best calculated to detach its head from the articulation1 yet it is always broken4 ,illustration3 ,fig4 ,,lvii4 #a1 c4 ,ligaments connecting the ribs to the vertebr behind4 ,while thus firmly attached to their points of support1 the ligaments1 which fix them1 are so disposed as to render the ribs capable of being readily moved upwards and downwards3 upwards in inspiration2 downwards in expiration2 and it is by this alternate action that they enlarge and diminish the cavity of the thorax in the function of respiration4 ,illustration3 ,fig4 ,,lviii4 ,ligaments joining the cartilages of the ribs to the sternum4 #ajc4 ,such are the boundaries of the cavity of the thorax as far as its walls are solid4 ,the interspaces between these solid portions at the sides are filled up by muscles1 principally by those termed the intercostal 7fig4 ,,lix472 below1 the boundary is formed by the diaphragm 7fig4 ,,lxi4 #b72 while above1 as has been already stated 7#fi71 the cavity is so contracted as only to leave an opening for the passage of certain parts to and from the chest4 ,illustration3 ,fig4 ,,lix4 ,a view of the muscles called ,intercostals1 filling up the spaces between the ribs4 #ajd4 ,the inner surface of the walls of the thorax1 in its whole extent1 is lined by a serous membrane1 exceedingly thin and delicate1 but still firm1 called the pleura4 ,the same membrane is reflected over the organs of respiration contained in the cavity1 so as to give them an external coat4 ,the membrane itself is every where continuous1 and every where the same1 whether it line the containing or the contained parts2 but it receives a different name as it covers the one or the other3 that portion of it which lines the walls of the cavity being called the costal pleura 7fig4 ,,lxi4 a71 while that which covers the organs contained in the cavity is termed the pulmonary pleura 7fig4 ,,lx4 #e1 #a74 #aje4 ,a fold of each pleura passes directly across the central part of the cavity of the thorax2 extending from the spinal column to the sternum1 and dividing the general cavity into two4 ,this portion of the pleura is called the mediastinum1 from its situation in the centre of the thorax1 and it so completely divides the thoracic cavity into two1 that the organs on one side of the chest have no communication with those of the other2 so that there may be extensive disease in one cavity 7for example1 a large accumulation of water17 while the other may be perfectly sound4 #ajf4 ,the main organs contained in the cavity of the thorax are the lungs with their air tube2 the heart with its great vessels2 and the tube passing from the mouth to the stomach 7fig4 ,,lx474 #ajg4 ,the two lungs occupy the sides of the chest 7fig4 ,,lx4 #e74 ,they are completely separated from each other by the membranous partition just described1 the mediastinum4 ,between the two folds of the mediastinum1 namely1 in the middle of the chest1 but inclining somewhat to the left side1 is placed the heart1 enveloped in another serous membrane1 the pericardium 7fig4 ,,lx4 #b1 #a74 #ajh4 ,the lungs are moulded to the cavities they fill2 whence their figure is conical1 the base of the cone being downwards1 resting on the diaphragm 7fig4 ,,lx4 #e1 b72 and the apex upwards1 towards the neck 7fig4 ,,lx4 #e74 #aji4 ,that surface of each lung which corresponds to the walls of the chest is convex in its whole extent 7fig4 ,,lx4 #e72 on the contrary1 that surface which corresponds to the mediastinum is flattened 7fig4 ,,lx4 #e74 ,the basis of the lung is concave1 adapted to the convexity of the diaphragm on which it rests 7fig4 ,,lx4 #e74 #aaj4 ,the air-vessel of the lungs1 termed the bronchus1 together with the blood-vessels and nerves1 enter the organ at its flattened side1 not exactly in the middle1 but rather towards the upper and back part4 ,this portion is termed the root of the lung4 #aaa4 ,the lungs are attached to the neck by the trachea 7fig4 ,,lx4 #d71 the continuation of which forms the bronchus2 to the spinal column by the pleura1 and to the heart by the pulmonary vessels 7fig4 ,,lx4 #c1 d73 their remaining portion is free and unattached4 #aab4 ,in the living body1 the lungs on each side completely fill the cavity of the chest1 following passively the movements of its walls1 and accurately adapting themselves to its size1 whether its capacity enlarge in inspiration1 or diminish in expiration1 so that the external surface of the lung 7the pulmonary pleura7 is always in immediate contact with the lining membrane of the walls of the cavity 7the costal pleura72 consequently1 during life1 there is no cavity1 the chest being always completely full4 ,illustration3 ,fig4 ,,lx4 a4 ,the cut edges of the ribs1 forming the lateral boundaries of the cavity of the thorax4 b4 ,the diaphragm1 forming the inferior boundary of the thorax1 and the division between the thorax and the abdomen4 c4 ,the cut edges of the abdominal muscles1 turned aside1 exposing the general cavity of the abdomen4 #a4 ,the cut edge of the pericardium turned aside4 #b4 ,the heart4 #c4 ,the great vessels in immediate connexion with the heart4 #d4 ,the trachea1 or wind-pipe4 #e4 ,the lungs4 #f4 ,the liver4 #g4 ,the stomach4 #h4 ,the large intestine4 #i4 ,the small intestines4 #aj4 ,the urinary bladder4 #aac4 ,the anterior surface of the pericardium1 the bag which envelopes the heart1 lies immediately behind the sternum1 and the cartilages of the second1 third1 fourth1 and fifth ribs1 covered at its sides by the pleura1 and firmly attached below to the diaphragm 7fig4 ,,lx4 #a74 #aad4 ,surrounded by its pericardium1 within the mediastinum1 the heart is placed nearly in the centre of the chest1 but its direction is somewhat oblique1 its apex being directly opposite to the interval between the fifth and sixth ribs on the left side 7fig4 ,,lx4 #b72 while its basis is directed upwards1 backwards1 and towards the right 7fig4 ,,lx4 #b74 ,that portion of its surface which is presented to view on opening the pericardium is convex 7fig4 ,,lx4 #b72 but its opposite surface1 namely1 that which rests upon the part of the pericardium which is attached to the diaphragm1 is flattened 7fig4 ,,lx4 #a74 ,it is fixed in its situation partly by the pericardium and partly by the great vessels that go to and from it4 ,but under the different states of expiration and inspiration1 it accompanies1 in some degree1 the movements of the diaphragm2 and in the varied postures of the body1 the heart deviates to a certain extent from the exact position here described4 #aae4 ,the second division of the trunk1 the abdomen1 is bounded above by the diaphragm 7fig4 ,,lxi4 #b71 below by the pelvis 7fig4 ,,lxi4 #c71 behind and at the sides by the vertebr and muscles of the loins 7fig4 ,,lxiii471 and before by the abdominal muscles 7fig4 ,,lxiii4 #i74 #aaf4 ,the organ which forms the superior boundary of the abdomen1 the diaphragm 7midriff71 is a circular muscle1 placed transversely across the trunk1 nearly at its centre 7fig4 ,,lxi4 #b74 ,it forms a vaulted partition between the thorax and the abdomen 7fig4 ,,lxi4 #b74 ,all around its border it is fleshy 7fig4 ,,lxi4 #b72 towards its centre it is tendinous 7fig4 ,,lxi4 #b72 the surface towards the abdomen is concave 7fig4 ,,lxi4 #b72 that towards the thorax convex 7fig4 ,,lxi4 #b72 while its middle tendinous portion ascends into the thorax as high as the fourth rib 7fig4 ,,lxi4 #b74 ,illustration3 ,fig4 ,,lxi4 ,view of the diaphragm4 #a4 ,cavity of the thorax2 #b4 diaphragm separating the cavity of the thorax from that of the abdomen2 #c4 cavity of the pelvis4 #aag4 ,the diaphragm is perforated by several apertures1 for the transmission of tubes and vessels1 which pass reciprocally between the thorax and abdomen 7fig4 ,,lxii474 #a4 ,a separate aperture is formed to afford an exit from the thorax of the aorta1 the common source of the arteries 7fig4 ,,lxii4 #b71 and an entrance into the thorax of the thoracic duct1 the tube that bears the digested aliment to the heart4 #b4 ,a little to the left of the former1 there is another aperture1 through which passes the esophagus or gullet 7fig4 ,,lxii4 #c71 the tube that conveys the food from the mouth to the stomach4 #c4 ,on the right side1 in the tendinous portion of the diaphragm1 very carefully constructed1 is a third aperture for the passage of the vena cava 7fig4 ,,lxii4 #d71 the great vessel that returns the blood to the heart from the lower parts of the body4 ,illustration3 ,fig4 ,,lxii4 ,view of the diaphragm with the tubes that pass through it4 #a4 ,arch of the diaphragm2 #b4 the trunk of the aorta passing from the chest into the abdomen2 #c4 the esophagus passing from the chest through the diaphragm to the stomach2 #d4 the vena cava1 the great vein that returns the blood to the heart from the lower parts of the body1 passing from the abdomen1 into the chest1 in its way to the right side of the heart2 #e4 #f4 muscles that arise in the interior of the trunk and that act upon the thigh2 #e4 the muscle called psoas2 #f4 the muscle called iliacus4 #aah4 ,the partition formed by the diaphragm between the thorax and abdomen1 though complete1 is moveable2 for as the diaphragm descends in inspiration and ascends in expiration1 it proportionally enlarges or diminishes the cavities between which it is placed2 consequently1 the actual magnitude of these cavities varies every moment1 and the size of the one is always in the inverse ratio of that of the other4 #aai4 ,between the abdomen and the pelvis there is no separation2 one cavity is directly continuous with the other 7fig4 ,,lxi4 #c72 but along the inner surface of the expanded bones1 which form a part of the lateral boundary of the abdomen1 there is a prominent line1 termed the brim of the pelvis 7fig4 ,,xlv4 #ae71 marking the point at which the abdomen is supposed to terminate and the pelvis to commence4 #abj4 ,behind and at the sides the walls of the abdomen are completed partly by the lumbar portion of the spinal column and partly by the lumbar muscles 7fig4 ,,xlv4 #d71 and before by the abdominal muscles 7fig4 ,,lxiii4 #i74 #aba4 ,the inner surface of the walls of the abdomen is lined throughout by a serous membrane1 termed the peritoneum 7fig4 ,,lxiii474 ,from the walls of the abdomen1 the peritoneum is reflected upon the organs contained in the cavity1 and is continued over them so as to form their external coat4 ,the peritoneum also descends between the several organs1 connecting them together1 and holding them firmly in their situation2 and it likewise forms numerous folds1 in which are embedded the vessels and nerves that supply the organs4 ,it secretes a serous fluid1 by which its own surface and that of the organs it covers is rendered moist1 polished1 and glistening1 and by means of which the organs glide smoothly over it1 and over one another in the various movements of the body1 and are in constant contact without growing together4 ,in structure1 distribution1 and function1 the peritoneum is thus perfectly analogous to the pleura4 #abb4 ,like the thorax1 the abdomen is always completely full4 ,when the diaphragm is in action1 it contracts4 ,when the diaphragm is in the state of contraction1 the abdominal and lumbar muscles are in the state of relaxation4 ,by the contraction of the diaphragm1 the organs contained in the abdomen are pushed downwards1 and the anterior and lateral walls of the cavity being at this moment in a state of relaxation1 they readily yield1 and1 consequently1 the viscera are protruded forwards and at the sides4 ,but the abdominal and lumbar muscles in their turn contract1 the diaphragm relaxing2 and1 consequently1 the viscera1 forced from the front and sides of the abdomen1 are pushed upwards1 together with the diaphragm1 into the cavity of the thorax4 ,a firm and uniform pressure is thus at all times maintained upon the whole contents of the abdomen3 there is an exact adaptation of the containing to the contained parts1 and of one organ to another4 ,no space intervenes either between the walls of the abdomen and the organs they enclose1 or between one organ and another3 so that the term cavity does not denote a void or empty space1 but merely the extent of the boundary within which the viscera are contained4 #abc4 ,the contents of the abdomen consist of the organs which belong to the apparatus of digestion1 and of those which belong to the apparatus of excretion4 #abd4 ,the organs which belong to the apparatus of digestion are--#a4 ,the stomach 7fig4 ,,lxiii4 #b7 #b4 ,the duodenum 7fig4 ,,lxiii4 #d74 #c4 ,the jejunum 7fig4 ,,lxiii4 #e74 #d4 ,the ilium 7fig4 ,,lxiii4 #e74 ,the three last organs are called the small intestines1 and their office is partly to carry on the digestion of the aliment commenced in the stomach1 and partly to afford an extended surface for the absorption of the nutriment as it is prepared from the aliment4 #e4 ,the pancreas 7fig4 ,,lxiv4 #e74 #f4 ,the liver 7fig4 ,,lxiv4 #b74 #g4 ,the spleen 7fig4 ,,lxiv4 #d74 ,the three last organs truly belong to the apparatus of digestion1 and their office is to co-operate with the stomach and the small intestines in the conversion of the aliment into nutriment4 ,illustration3 ,fig4 ,,lxiii4 #a4 ,esophagus2 #b4 stomach2 #c4 liver raised1 showing its under surface2 #d4 duodenum2 #e4 small intestines2 #f4 ccum2 #g4 colon2 #h4 urinary bladder2 #i4 gall bladder2 #aj4 abdominal muscles divided and reflected4 #abe4 ,the organs which belong to the apparatus of excretion are--#a4 ,the large intestines consisting of the ccum 7fig4 ,,lxiii4 #f74 #b4 ,the colon 7fig4 ,,lxiii4 #g74 #c4 ,the rectum 7fig4 ,,lxiv4 #aj74 ,it is the office of these organs1 which are called the large intestines1 to carry out of the system that portion of the alimentary mass which is not converted into nourishment4 #d4 ,the kidneys 7fig4 ,,lxiv4 #f71 the organs which separate in the form of the urine an excrementitious matter from the blood1 in order that it may be conveyed out of the system4 ,illustration3 ,fig4 ,,lxiv4 ,general view of the viscera of the abdomen4 #a4 ,stomach raised2 #b4 under surface of liver2 #c4 gall bladder2 #d4 spleen2 #e4 pancreas2 #f4 kidneys2 #g4 ureters2 #h4 urinary bladder2 #i4 portion of the intestine called duodenum2 #aj4 portion of the intestine called rectum2 #aa4 the aorta4 #abf4 ,the last division of the trunk1 called the pelvis 7fig4 ,,lxi4 #c71 consists of a circle of large and firm bones1 interposed between the lower portion of the trunk and the inferior extremities 7fig4 ,,xlv474 ,the bones that compose the circle1 distinct in the child1 are firmly united in the adult into a single piece2 but as the original separation between each remains manifest1 they are always described as separate bones4 ,they are the sacrum 7fig4 ,,xlv4 #e71 the coccyx 7fig4 ,,xxxv471 the ilium 7fig4 ,,xlv4 #aa71 the ischium 7fig4 ,,xlv4 #ab71 and the pubis 7fig4 ,,xlv4 #ac74 #abg4 ,the sacrum1 placed like a wedge between the moveable portion of the spinal column and the lower extremities1 forms the posterior boundary of the pelvis4 ,the figure of this bone is triangular 7fig4 ,,xlv4 #e72 its anterior surface is concave and smooth1 for enlarging the cavity of the pelvis and sustaining the organs contained in it 7fig4 ,,xlv4 #e72 its posterior surface is convex1 irregular1 and rough 7fig4 ,,xxxv471 giving origin to the great muscles that form the contour of the hip1 and to the strong muscles of the back and loins that raise the spine and maintain the trunk of the body erect4 #abh4 ,the base or upper part of the sacrum receives the last vertebra of the loins on a large and broad surface 7fig4 ,,xlv4 #d71 forming a moveable joint2 and the degree of motion at this point is greater than it is at the higher points of the spinal column4 ,firmly united at its sides with the haunch bones1 it admits there of no degree of motion4 #abi4 ,the coccyx1 so named from its resemblance to the beak of the cuckoo1 when elongated by a succession of additional bones1 forms the tail in quadrupeds2 but in man it is turned inwards to support the parts contained in the pelvis1 and to contract the lower opening of the cavity4 ,by means of a layer of cartilage1 the medium by which this bone is connected with the sacrum1 it forms a moveable articulation1 continuing moveable in men until the age of twenty-five1 and in women until the age of forty-five2 continuing moveable in women thus long1 in order that by yielding to the force which tends to push it backwards during the period of labour1 it may enlarge the lower aperture of the pelvis1 and so facilitate the process of parturition and diminish its suffering4 #acj4 ,the lateral boundaries of the pelvis are formed by the ilium1 the haunch bone 7fig4 ,,xlv4 #aa71 and by the ischium1 the hip bone 7fig4 ,,xlv4 #ab74 ,the ilium forms the lower part of the abdomen and the upper part of the pelvis 7fig4 ,,xlv4 #aa72 its broad expanded wing supports the contents of the abdomen1 and gives attachment to the muscles that form the anterior portion of its walls 7figs4 ,,xlv4 #aa1 and ,,lxiii4 #i72 its external convex surface sustains the powerful muscles that extend the thigh2 and along its internal surface is the prominent line which marks the brim of the pelvis 7fig4 ,,xlv4 #ae71 and which divides this cavity from that of the abdomen4 #aca4 ,the ischium or hip bone is the lower part of the pelvis 7fig4 ,,xlv4 #ab72 at its undermost portion is a rounded prominence called the tuberosity 7fig4 ,,xlv4 #ab71 in its natural condition covered with cartilage1 upon which is superimposed a cushion of fat4 ,it is this part on which the body is supported in a sitting posture4 #acb4 ,the pubis or share bone forms the upper and fore part of the pelvis 7fig4 ,,xlv4 #ac71 and together with the two former bones1 completes the large and deep socket1 termed the acetabulum 7fig4 ,,xlv4 #ad71 into which is received the head of the thigh-bone 7fig4 ,,xxxiv4 #d74 ,the margin of the acetabulum and the greater part of its internal surface is lined with cartilage1 so that in its natural condition it is much deeper than it appears to be when the bones alone remain4 #acc4 ,the lower aperture of the pelvis1 which appears large when all the soft parts are removed1 is not really large1 for in its natural state it is filled up partly by muscles and partly by ligaments1 which sustain and protect the pelvic organs1 leaving only just space enough for the passage to and from those which have their opening on the external surface4 #acd4 ,the cavity of the pelvis1 together with all the organs contained in it1 are lined by a continuation of the membrane that invests the abdomen and its contents4 #ace4 ,the organs contained in the pelvis are the rectum 7fig4 ,,lxiv4 #i71 which is merely the termination of the large intestines1 the urinary bladder 7fig4 ,,lxiv4 #h71 and the internal part of the apparatus of reproduction4 #acf4 ,the large and strong bones of the pelvis not only afford lodgment and protection to the tender organs contained in its cavity1 but sustain the entire weight of the body1 the trunk resting on the sacrum as on a solid basis 7fig4 ,,xlv4 #e71 and the lower extremities being supported in the sockets in which the heads of the thigh-bones play1 in the varied movements of locomotion 7fig4 ,,xxxiv4 #d74 #acg4 ,the last division of the body comprehends the superior and the inferior extremities4 #ach4 ,the superior extremities consist of the shoulder1 arm1 fore-arm1 and hand4 #aci4 ,the soft parts of the ,,shoulder are composed chiefly of muscles2 its bones are two1 the scapula or the blade bone1 and the clavicle or the collar bone 7fig4 ,,lxv4 #b1 #d74 ,illustration3 ,fig4 ,,lxv4 #a4 ,sternum2 #b4 clavicle2 #c4 ribs2 #d4 anterior surface of scapula2 #e4 coracoid process of scapula2 #f4 acromion process of scapula2 #g4 margin of glenoid cavity of scapula2 #h4 body of the humerus or bone of the arm2 #i4 head of the humerus4 #adj4 ,the ,,scapula is placed upon the upper and back part of the thorax1 and occupies the space from the second to the seventh ribs 7fig4 ,,lxv4 #d7 ,illustration3 ,fig4 ,,lxvi4 #a4 ,posterior surface of scapula2 #b4 margin of scapula2 #c4 acromion process2 #d4 margin of glenoid cavity2 #e4 clavicle2 #f4 body of humerus2 #g4 head of humerus4 ,unlike that of any other bone of the body1 it is embedded in muscles1 without being attached to any bone of the trunk1 excepting at a single point4 ,from the bones of the thorax it is separated by a double layer of muscles1 on which it is placed as upon a cushion1 and over the smooth surface of which it glides4 ,originally1 like the bones of the skull1 it consisted of two tables of compact bone1 with an intermediate layer of spongy bony substance 7diplo72 but1 by the pressure of the muscles that act upon it1 it gradually grows thinner and thinner1 until1 as age advances1 it becomes in some parts quite transparent and as thin as a sheet of paper4 #ada4 ,the figure of the scapula is that of an irregular triangle 7fig4 ,,lxvi474 ,its anterior surface is concave 7fig4 ,,lxv4 #d71 corresponding to the convexity of the ribs 7fig4 ,,xlv4 #g72 its posterior surface is very irregular 7fig4 ,,lxvi4 #a71 being in some parts concave and in others convex1 giving origin especially to two large processes 7figs4 ,,lxv4 #e1 and ,,lxvi4 #c72 one of which is termed the acromion 7fig4 ,,lxvi4 #c71 and the other the coracoid process of the scapula 7fig4 ,,lxv4 #e74 ,the margins of the bone1 whatever the thinness of some portions of it1 are always comparatively thick and strong 7fig4 ,,lxvi4 #b71 affording points of origin or of insertion to powerful muscles4 ,at what is called the anterior angle of the bone there is a shallow oval depression covered with cartilage and deepened by a cartilaginous margin1 called the glenoid cavity of the scapula 7figs4 ,,lxv4 #g1 and ,,lxvi4 #d71 which receives the head of the humerus or bone of the arm 7figs4 ,,lxv4 #i1 and ,,lxvi4 #g1 #f74 #adb4 ,the clavicle1 the second bone of the shoulder1 is a long and slender bone1 of the form of an italic ,illustration1 projecting a little forwards towards its middle1 so as to give a slight convexity of outline to the top of the chest and the bottom of the neck 7fig4 ,,lxv4 #b74 ,it is attached by one extremity to the sternum 7fig4 ,,lxv4 #b7 and by the other to the scapula 7fig4 ,,lxv4 #b71 by moveable joints4 ,the nature of an immoveable joint has been explained 7#fc74 ,in the connexion of the bones of the trunk1 while the main object is to secure firmness of attachment1 some degree of motion is at the same time obtained 7#ha et seq473 but the mode in which the several bones of the extremities are connected with each other and with the trunk1 admits of so great a degree of motion1 that these articulations are pre-eminently entitled to the name of moveable joints4 ,the component parts of all moveable joints are bone1 cartilage1 synovial membrane1 and ligament4 ,the great character of a moveable joint is the approximation of two or more bones2 yet these bony surfaces are never in actual contact1 but are invariably separated from each other by cartilage4 ,the cartilage either covers the entire extent of the articulating surface of the bones1 as in the shoulder-joint1 where both the head of the humerus and the cavity of the scapula that receives it are enveloped in this substance 7fig4 ,,lxv4 #g4 #i71 or a portion of it is placed between the articulating surfaces of the bones1 as in the joint between the clavicle and sternum 7fig4 ,,lxvii4 a72 which1 when so placed1 is termed an interarticular cartilage 7fig4 ,,lxvii4 a74 ,by its smooth surface cartilage lessens friction2 while by its elasticity it facilitates motion and prevents concussion4 ,slightly organized cartilage is provided with comparatively few blood-vessels and nerves4 ,had it been vascular and sensible like the skin and the muscle1 the force applied in the movements of the joint would have stimulated the blood-vessels to inordinate action1 and the sensibility of the nerves would have been the source of constant pain3 every motion of every joint would have been productive of suffering1 and have laid the foundation of disease4 ,the facility and ease of motion obtained by the smoothness1 elasticity1 and comparative insensibility of cartilage are still further promoted by the fluid which lubricates it1 termed synovia1 secreted by a membrane called synovial1 which lines the internal surface of the joint1 and which bears a close resemblance to the serous 7#cj74 ,synovia is a viscid fluid of the consistence of albumen 7#e74 ,it is to the joint what oil is to the wheel1 preventing abrasion and facilitating motion2 but it is formed by the joint itself1 at the moment when needed1 and in the quantity required4 ,the motion of the joint stimulates the synovial membrane to secretion1 and hence the greater the degree of motion1 the larger the quantity of lubricating fluid that is supplied4 ,the several parts of the apparatus of moveable joints are retained in their proper position by ligamentous substance1 which1 as has been shown 7#if and #ig71 is oftentimes so strong that it is easier to fracture the bone than to tear the ligament1 and in every case the kind and extent of motion possessed by the joint are dependent mainly on the form of the articulatory surfaces of the bones and on the disposition of the ligaments4 #adc4 ,in the joint formed by the clavicle and the sternum 7fig4 ,,lxvii4 a7 an interarticular cartilage is placed between the two bones which are united1 first by a strong fibrous ligament1 which envelops them as in a capsule 7fig4 ,,lxvii4 #a72 by a second ligament1 which extends from the cartilage of the first rib to the clavicle 7fig4 ,,lxvii4 #d71 by which the attachment of the clavicle to the sternum is materially strengthened2 and by a third ligament which passes transversely from the head of one clavicle to that of the other 7fig4 ,,lxvii4 #c74 ,the joint thus formed1 though so strong and firm that the dislocation of it is exceedingly rare1 yet admits of some degree of motion in every direction1 upwards1 downwards1 forwards1 and backwards2 and this articulation is the sole point by which the scapula is connected with the trunk1 and consequently by which the upper extremity can act1 or be acted upon1 by the rest of the body4 ,illustration3 ,fig4 ,,lxvii4 #a4 ,the fibrous capsule of the sternum and clavicle2 #b4 the same laid open1 showing a1 the interarticular cartilage2 #c4 the ligament connecting the two clavicles2 #d4 the ligament joining the clavicle to the first rib2 #e4 ligaments passing down in front of the sternum4 #add4 ,the scapular extremity of the clavicle 7fig4 ,,lxviii4 #f7 is attached to the processes of the scapula 7fig4 ,,lxviii4 #d4 #c7 by several ligaments of great strength 7fig4 ,,lxviii4 #g1 #h1 #i74 ,first by very strong fasciculi which pass from the upper surface of the clavicle to the acromion of the scapula 7fig4 ,,lxviii4 #f72 and secondly by two ligaments which unite the clavicle with the coracoid process of the scapula 7fig4 ,,lxviii4 #h1 #i74 ,these ligaments are so powerful that they resist a force capable of fracturing the clavicle2 and they need to be thus strong1 for the clavicle is a shaft which sustains the scapula1 and through the scapula the whole of the upper extremity2 and the main object of the joint by which these bones are united1 is to afford a firm attachment of the scapula to its point of support4 ,illustration3 ,fig4 ,,lxviii4 #a4 ,the clavicle2 #b4 the anterior part of the scapula2 #c4 the coracoid process2 #d4 the acromion process2 #e4 the humerus2 #f4 ligaments binding the scapular end of the clavicle to the acromion2 #g4 #h4 #i4 ligaments passing from one process of the scapula to the other2 #aj4 the fibrous capsule of the shoulder-joint4 #ade4 ,the clavicle serves the following uses3 it sustains the upper extremity2 it connects the upper extremity with the thorax2 it prevents the upper extremity from falling forwards upon the thorax2 and it affords a fixed point for steadying the extremity in the performance of its various actions4 #adf4 ,the glenoid cavity of the scapula 7fig4 ,,lxv4 #g7 receives the head of the humerus1 the bone of the arm 7fig4 ,,lxv4 #i71 and the two bones being united by ligament form the shoulder-joint 7fig4 ,,lxviii474 ,this joint is what is termed a ball and socket joint1 the peculiarities of which are two3 first1 beyond all others this mode of articulation admits of free and extensive motion2 in the present case1 there is the utmost freedom of motion in every direction1 upwards1 downwards1 backwards1 and forwards4 ,in the second place1 this mode of articulation admits of the motion of the limb without that of the body1 or of the motion of the body without that of the limb4 ,when at rest1 the arm may be moved in almost any direction without disturbing the position of any other part of the frame2 the manifold advantages of which are obvious4 ,on the other hand1 by careful management1 very considerable variations in the posture of the body may be effected without the communication of any degree of motion to the limb2 an unspeakable advantage when the limb has sustained injury1 or is suffering from disease4 #adg4 ,it does not seem possible to construct a joint of great strength1 capable1 at the same time1 of the degree of motion possessed by the joint of the shoulder4 ,so shallow is the socket of the scapula1 and so large the head of the humerus1 that it seems as if the slightest movement must dislodge it from its cavity 7fig4 ,,lxvi4 #d4 #g74 ,for sustaining heavy weights or resisting a great amount of pressure1 applied to it suddenly and in various directions1 the arm is obviously unfitted4 ,but this is not its office4 ,the superior extremities are the organs of apprehension--the instruments by which the mind executes the commands of the will4 ,they do not need the strength required by the organs that sustain the weight of the body and that perform the function of locomotion2 but they do need freedom and extent of motion3 to this strength may be sacrificed1 and so it is2 yet what can be done to combine strength with mobility is effected4 ,large and strong processes of bone1 proceeding as has been shown 7#ada71 from the convex surface of the scapula 7figs4 ,,lxv4 and ,,lxvi471 overhang1 and to a considerable extent surround1 the head of the arm-bone1 especially resisting the force that would dislodge it from its socket and drive it upwards1 inwards1 and backwards 7fig4 ,,lxv471 the directions in which force is most commonly applied to it4 ,by these processes of bone the joint is greatly strengthened1 especially in those directions4 ,moreover1 a strong ligament1 termed the fibrous capsule 7fig4 ,,lxviii4 #aj7 envelops the joint4 ,this ligament1 arising from the neck of the scapula 7fig4 ,,lxviii4 #aj71 expands itself in such a manner as completely to surround the head of the humerus 7fig4 ,,lxviii4 #aj72 and then again contracts in order to be inserted into the neck of the bone 7fig4 ,,lxviii4 #aj74 ,this ligament is strengthened by the tendons of no less than four muscles which are expanded over it1 as well as by the powerful substance termed fascia which is reflected upon it from both the processes and ligaments of the scapula4 ,in addition to all these expedients for fortifying the joint1 it receives a further security in the position of the scapula1 which is loose and unattached2 which slides easily over the ribs upon its cushion of flesh2 which thus obtains1 by its facility of yielding1 some compensation for its want of strength1 eluding the force which it cannot resist4 #adh4 ,the arm consists of numerous and powerful muscles1 and of a single bone1 the humerus1 which belongs to the class of bones termed cylindrical 7#ahe74 #adi4 ,the upper end of the humerus terminates in a circular head 7fig4 ,,lxv4 #i71 which is received into the socket of the scapula 7fig4 ,,lxv4 #i4 #g7 termed1 as has been stated 7#ada71 its glenoid cavity4 ,the middle portion of the bone1 or what is termed its shaft 7fig4 ,,lxv4 #h71 diminishes considerably in magnitude1 and becomes somewhat rounded 7fig4 ,,lxv4 #h71 while its lower end again enlarges1 and is spread out into a flattened surface of great extent 7fig4 ,,lxix4 #a1 #c1 #b1 #d74 ,of this broad flattened surface1 the middle portion is grooved 7fig4 ,,lxix4 #b73 it is covered with cartilage2 it forms the articulating surface by which the arm is connected with the fore-arm4 ,on each side of this groove there is a projection of bone or tubercle1 termed condyle 7fig4 ,,lxix4 #c1 #d71 the inner 7fig4 ,,lxix4 #c7 being much larger than the outer 7fig4 ,,lxix4 #d74 ,the inner condyle gives origin to the muscles that bend1 the outer to those that extend the fore-arm and the fingers 7figs4 ,,lxxxiv4 #a1 #b1 and ,,lxxxv4 #a74 ,illustration3 ,fig4 ,,lxix4 #a4 ,lower extremity of the humerus2 #b4 grooved surface2 #c4 internal condyle2 #d4 external condyle2 #e4 the upper part of the ulna2 #f4 the head2 #g4 the neck2 #h4 the tubercle of the radius4 #aej4 ,the muscles that act upon the arm arise from the back 7fig4 ,,lxxii4 #b71 the chest 7fig4 ,,lxxi4 #a71 the clavicle 7fig4 ,,lxxi4 #a71 and the scapula 7fig4 ,,lxxi4 #c72 and they move the arm with freedom and power upwards1 downwards1 forwards1 backwards1 inwards1 and outwards4 ,the chief muscle that raises the arm is the deltoid 7fig4 ,,lxxi4 #c71 which arises partly from the clavicle and partly from the scapula 7fig4 ,,lxxi4 #c74 ,it has the appearance of three muscles proceeding in different directions1 the different portions being separated by slight fissures 7figs4 ,,lxxi4 #c1 and ,,lxxii4 #c74 ,the fibres converging unite and form a powerful muscle which covers the joint of the humerus 7fig4 ,,lxxi4 #c74 ,it is implanted by a short and strong tendon into the middle of the humerus 7fig4 ,,lxxi4 #d74 ,its manifest action is to pull the arm directly upwards4 ,its action is assisted by the muscles that cover the back of the scapula1 which are in like manner inserted into the humerus1 and which1 at the same time that they elevate the arm1 support it when raised4 ,illustration3 ,fig4 ,,lxxi4 ,view of the muscles on the fore part of the chest that act upon the arm4 #a4 ,the muscle called the great pectoral2 #b4 the small pectoral2 #c4 the deltoid2 #d4 the humerus4 #aea4 ,the principal muscle that carries the arm downwards is the latissimus dorsi 7fig4 ,,lxxii4 #b71 the broadest muscle of the body1 which1 after having covered all the lower part of the back and loins1 terminates in a thin but strong tendon which stretches to the arm1 and is implanted into the humerus 7fig4 ,,lxxii4 #b71 near the tendon of a muscle immediately to be described1--the great pectoral4 ,when the arm is raised by the deltoid and its assistant muscles1 the latissimus dorsi carries it downwards with force1 and its powerful action is increased by that of other muscles which arise from the scapula and are inserted into the arm4 #aeb4 ,the principal muscle that carries the arm forwards towards the chest1 is the great pectoral 7fig4 ,,lxxi4 #a71 which1 arising partly from the clavicle 7fig4 ,,lxxi4 #a71 partly from the sternum 7fig4 ,,lxxi4 #a71 and partly from the cartilages of the second1 third1 fourth1 fifth1 and sixth ribs 7fig4 ,,lxxi4 #a71 covers the greater part of the breast 7fig4 ,,lxxi4 #a74 ,its fibres1 converging1 terminate in a strong tendon1 which is inserted near the tendon of the longissimus dorsi into the humerus1 about four inches below its head 7fig4 ,,lxxi4 #a74 ,these two muscles form the axilla or armpit1 the anterior border of the axilla consisting of the pectoral muscle4 ,though each of these muscles has its own peculiar office1 yet they often act in concert1 thereby greatly increasing their power1 and the result of their combined action is to carry the arm either directly downwards or to the side of the chest4 ,illustration3 ,fig4 ,,lxxii4 ,view of the muscles seated on the back part of the trunk that act upon the shoulder and arm4 #a4 ,the muscle called the trapezius2 #b4 the latissimus dorsi2 #c4 the deltoid4 #aec4 ,some of the muscles that elevate the arm carry it inwards1 and others outwards2 the muscles that carry it forwards likewise carry it inwards2 while of the muscles that pull it downwards1 some direct it forwards and inwards1 and others backwards and outwards 7#aea and #aeb74 #aed4 ,it has been already stated that the shoulder-joint is completely surrounded by the muscular fibres or the tendinous expansions of several of these powerful muscles1 which have a far greater effect in maintaining the head of the humerus in its socket than the fibrous capsule of the joint2 the latter being necessarily loose1 in order to allow of the extended and varied motions of the arm1 whereas the muscles that encompass the joint adhere closely and firmly to it4 ,moreover1 by virtue of their vital power these muscles act with an efficiency which a mere ligamentous band is incapable of exerting2 for they apportion the strength of resistance to the separating force1 and react with an energy proportioned to the violence applied4 #aee4 ,the bones of the fore-arm are two1 the ulna and the radius 7figs4 ,,lxix4 and ,,lxxiii474 ,the ulna is essentially the bone of the elbow 7figs4 ,,lxix4 #e1 and ,,lxxiii4 #c72 the radius that of the hand 7fig4 ,,lxxv474 ,supposing the arm to hang by the side of the body1 and the palm of the hand to be turned forwards1 the ulna1 in apposition with the little finger1 occupies the inner2 and the radius1 in apposition with the thumb1 occupies the outer part of the fore-arm 7fig4 ,,xxxiv4 #c74 ,illustration3 ,fig4 ,,lxxiii4 #a4 ,the internal condyle of the humerus2 #b4 the external condyle of the humerus2 #c4 the olecranon process of the ulna2 #d4 the head of the radius4 #aef4 ,the upper end of the ulna belonging to the elbow is large 7figs4 ,,lxix4 #e1 and ,,lxxiii4 #c74 ,it sends backwards the large projection commonly named the elbow or olecranon 7fig4 ,,lxxii4 #c71 in the centre of which there is a smooth and somewhat triangular surface 7fig4 ,,lxxiii4 #c7 which is always covered by skin of a coarse texture1 like that placed over the lower part of the knee-pan1 as if nature intended this for a part on which we may occasionally lean and rest4 ,large at the elbow1 the ulna gradually grows smaller and smaller as it descends towards the wrist1 where it ends in a small round head 7fig4 ,,lxxxii4 #b71 beyond which1 on the inner side1 or that corresponding to the little finger1 it projects downwards a small rounded point1 termed the styloid process 7fig4 ,,lxxxii4 #c74 ,as the styloid process and the olecranon1 the two extremities of the ulna 7figs4 ,,lxxiii4 #c1 and ,,lxxii4 #c71 are easily and distinctly felt1 the length of this bone was primitively used as a measure1 called a cubit1 which was the ancient name of the bone4 #aeg4 ,the radius1 the second bone of the fore-arm1 placed along its outer part next the thumb1 is small at its upper end 7figs4 ,,lxix4 #f1 and ,,lxxiii4 #d72 but its body is larger than that of the ulna2 while its lower end1 next the wrist to which it properly belongs1 is very bulky 7fig4 ,,lxxxii4 #a74 ,its upper end is formed into a small circular head1 which is united by distinct joints both to the humerus and to the ulna 7fig4 ,,lxix4 #f74 ,the top of its rounded head is excavated into a shallow cup 7figs4 ,,lxix4 #f1 and ,,lxxiii4 #d7 which receives a corresponding convexity of the humerus 7fig4 ,,lxix4 #b71 and its lower extremity is excavated into an oblong cavity1 which receives two of the bones of the wrist 7fig4 ,,lxxxiii4 #a4 #d74 #aeh4 ,the joint of the elbow is composed above of the condyles of the humerus 7fig4 ,,lxix4 #c4 #b71 and below by the heads of the ulna and radius 7fig4 ,,lxix4 #e4 #f74 #aei4 ,the upper surface of the ulna is so accurately adapted to the lower surface of the humerus that the one seems to be moulded on the other 7figs4 ,,lxix4 #e1 and ,,lxxiii4 #c71 and the form of these corresponding surfaces1 which are everywhere covered with cartilage1 is such as to admit of free motion backwards and forwards1 that is1 of extension and flexion2 but to prevent any degree of motion in any other direction4 ,the joint is therefore a hinge-joint1 of which the two motions of flexion and extension are the proper motions4 ,this hinge is formed on the part of the humerus by a grooved surface1 with lateral projections 7fig4 ,,lxix4 #b1 #c1 #d71 and on the part of the ulna by a middle projection with lateral depressions 7fig4 ,,lxix4 #e73 the middle projection of the ulna turning readily on the grooved surface of the humerus 7fig4 ,,lxix4 #b74 #afj4 ,the bones are held in their proper situation1 first1 by a ligament on the fore part of the arm1 called the anterior 7fig4 ,,lxxiv4 #f71 which arises from the lower extremity of the humerus1 and is inserted into the upper part of the ulna and the coronary ligament of the radius 7fig4 ,,lxxiv4 #f4 #h72 secondly1 by another ligament on the back part of the arm1 called the posterior ligament 7fig4 ,,lxxv4 #h71 placed in the cavity of the humerus that receives the olecranon of the ulna 7fig4 ,,lxxv4 #h72 and thirdly1 by two other ligaments at the sides of the ulna 7fig4 ,,lxxv4 #f1 #g74 ,the ulna and radius are united1 first1 by a ligament called the coronary1 which1 arising from the ulna1 passes completely around the head of the radius 7fig4 ,,lxxvi4 #c71 and the attachment of which1 while sufficiently close to prevent the separation of the two bones1 is yet not adherent to the radius1 for a reason immediately to be assigned2 secondly1 by another ligament which passes in an oblique direction from one bone to the other 7fig4 ,,lxxvi4 #d72 and thirdly1 by a dense and broad ligament1 termed the interosseous 7figs4 ,,lxxiv4 #aj1 and ,,lxxvi4 #e71 which fills up the space between the two bones nearly in their whole extent4 ,this ligament serves other offices besides that of forming a bond of union1 affording1 more especially1 a greater extent of surface for the attachment of muscles1 and separating the muscles on the anterior from those on the posterior part of the limb4 ,illustration3 ,fig4 ,,lxxiv4 ,anterior view of the ligaments of the elbow-joint4 #a4 ,the lower portion of the humerus2 #b4 the upper portion of the radius2 #c4 the upper portion of the ulna2 #d4 the internal condyle2 #e4 the external condyle2 #f4 the anterior ligament2 #g4 portion of the internal lateral ligament2 #h4 portion of the coronary ligament2 #i4 the oblique ligament2 #aj4 upper portion of the interosseous ligament4 ,illustration3 ,fig4 ,,lxxv4 ,posterior view of the ligaments of the elbow-joint4 #a4 ,lower end of the humerus2 #b4 internal condyle2 #c4 external condyle2 #d4 the olecranon process of the ulna2 #e4 the upper portion of the radius2 #f4 the internal lateral ligament2 #g4 the external lateral ligament2 #h4 the posterior ligament4 ,illustration3 ,fig4 ,,lxxvi4 ,view of the ligaments connecting the ulna and radius at their upper part4 #a4 ,the radius2 #b4 the ulna2 #c4 the coronary ligament surrounding the head of the radius2 #d4 the oblique ligament passing from the ulna to the tubercle of the radius2 #e the upper portion of the interosseous ligament4 #afa4 ,at their inferior extremities the ulna and radius are united partly by the interosseous ligament 7fig4 ,,lxxvii4 #a7 and partly by ligamentous fibres which pass transversely from one bone to the other 7fig4 ,,lxxvii4 #b7 on the anterior and the posterior surface of the fore-arm4 ,illustration3 ,fig4 ,,lxxvii4 #a4 ,interosseous ligament2 #b4 transverse fibres passing between the radius and ulna1 and uniting the two bones2 #c4 #d4 #e4 posterior and lateral ligaments of the wrist joint2 #f4 ligaments uniting the bones of the wrist with one another2 #g4 #h4 ligaments which attach the metacarpal to the carpal bones2 #i4 transverse ligaments for the attachment of the phalanges of the fingers2 #aj4 lateral ligaments for the attachment of the phalanges of the fingers #aa4 ligaments of the thumb4 #afb4 ,the lower extremity of the radius is also united to the wrist2 and the hand being attached to the wrist1 the junction of the hand and the fore-arm is effected by the articulation of the wrist with the radius 7fig4 ,,lxxvii474 ,the ligaments which connect the bones of the wrist with the radius are bands of exceeding strength 7fig4 ,,lxxvii4 #c74 #afc4 ,the muscles that act upon the fore-arm are placed upon the arm 7fig4 ,,lxxviii474 ,the joint of the elbow being a hinge-joint1 the fore-arm can admit only of two motions1 namely1 flexion and extension4 ,the muscles by which these motions are effected are four1 two for each2 the two flexors being placed on the fore part 7fig4 ,,lxxviii4 #b4 #d71 and the two extensors on the back part of the arm 7fig4 ,,lxxix4 #e74 #afd4 ,the two flexor muscles of the fore-arm are termed the biceps and the brachialis 7fig4 ,,lxxviii4 #b1 #d74 ,the biceps is so called because it has two distinct heads or points of origin 7fig4 ,,lxxviii4 #b71 both of which arise from the scapula 7fig4 ,,lxxviii4 #b74 ,about a third part down the humerus the two heads meet1 unite and form a bulky muscle 7fig4 ,,lxxviii4 #b71 which1 when it contracts1 may be felt like a firm ball on the fore part of the arm1 the upper part of the ball marking the point of union of the two heads 7fig4 ,,lxxviii4 #b74 ,the muscle gradually becoming smaller1 at length terminates in a rounded tendon 7fig4 ,,lxxviii4 #c71 which is implanted into the tubercle of the radius a little below its neck 7fig4 ,,lxxviii4 #c74 ,it is an exceedingly thick and powerful muscle1 and its manifest action is to bend the fore-arm with great strength4 ,but since its tendon is inserted into the radius1 besides bending the fore-arm1 it assists other muscles that also act upon the radius in the performance of a function to be described immediately 7#afh74 ,illustration3 ,fig4 ,,lxxviii4 ,view of the flexor muscles of the fore-arm4 #a4 ,the anterior surface of the scapula2 #b4 the muscle called biceps2 #c4 tendon of the biceps passing to the tubercle of the radius2 #d4 the muscle called brachialis4 #afe4 ,the second flexor of the fore-arm1 termed the brachialis1 is placed immediately under the biceps1 and is concealed by it for a considerable part of its course 7fig4 ,,lxxviii4 #d74 ,arising from the humerus1 on each side of the insertion of the deltoid1 it continues its attachment to the bone all the way down the fore part of the humerus1 to within inch of the joint2 it then passes over the joint1 adhering firmly to the anterior ligament 7fig4 ,,lxxviii4 #d71 and is inserted by a strong tendon into the ulna 7fig4 ,,lxxviii4 #d74 ,it is a thick and fleshy muscle1 powerfully assisting the action of the biceps4 #aff4 ,the two extensor muscles are named the triceps and the anconeous 7fig4 ,,lxxix474 ,the triceps1 seated on the back part of the arm1 derives its name from having three distinct points of origin1 or three separate heads 7fig4 ,,lxxix4 #e72 one of which arises from the scapula and two from the humerus 7fig4 ,,lxxix4 #e74 ,all these heads adhere firmly to the humerus1 as the brachialis does on the fore part of the arm1 down to within an inch of the joint 7fig4 ,,lxxix4 #e71 where they form a strong tendon1 which is implanted into the olecranon of the ulna 7fig4 ,,lxxix4 #c72 the projection of which affords a lever for increasing the action of the muscle4 ,in all animals that leap and bound1 this process of the ulna is increased in length in proportion to their power of performing these movements4 ,the triceps forms an exceedingly thick and strong muscle1 which envelops the whole of the back part of the arm 7fig4 ,,lxxix472 its action is simple and obvious2 it powerfully extends the fore-arm4 ,the anconeous1 a small muscle of a triangular form1 arising from the external condyle of the humerus1 and inserted into the ulna a little below the olecranon1 assists the action of the triceps4 ,illustration3 ,fig4 ,,lxxix4 ,view of the extensor muscles of the fore-arm4 #a4 ,the scapula2 #b4 the upper part of the humerus2 #c4 upper end of the ulna2 #d4 upper end of the radius2 #e4 the muscle called triceps1 the extensor of the fore-arm4 #afg4 ,such are the motive powers which act upon the fore-arm1 and which produce all the motions of which the hinge-joint of the elbow renders it capable4 ,but besides flexion and extension1 the fore-arm is capable of the motion of rotation1 which is accomplished by means of the radius4 ,it has been shown 7#aeg7 that the top of the rounded head of the radius is excavated into a shallow cup 7figs4 ,,lxix4 #f1 and ,,lxxiii4 #d7 which receives a corresponding convexity of the humerus 7figs4 ,,lxix4 #b1 and ,,lxxiii4 #b74 ,in consequence of this articulation with the humerus1 the radius1 like the ulna1 can move backwards and forwards in flexion and extension1 the proper movements of the hinge-joint2 but that portion of the margin of the hinge of the radius which is in apposition with the ulna is convex 7fig4 ,,lxix4 #f71 and is received into a semilunar cavity hollowed out in the ulna 7fig4 ,,lxix4 #e74 ,in this cavity the rounded head of the radius revolves1 the two bones being held together by the ligament already described 7#afj71 which surrounds the head of the radius 7fig4 ,,lxxvi4 #c71 and which holds it firmly without being adherent to it1 and without impeding in any degree the rotatory motion of the radius4 ,below1 the surface of the radius next the ulna is hollowed out into a semilunar cavity 7fig4 ,,lxxxii4 #a71 which receives a corresponding convex surface of the ulna 7fig4 ,,lxxxii4 #b71 upon which convex surface the radius rolls 7fig4 ,,lxxxii4 #a74 ,thus1 by the mode in which it is articulated with the ulna above1 the radius turns upon its own axis4 ,by the mode in which it is articulated with the ulna below1 the radius revolves upon the head of the ulna2 and1 in consequence of both articulations1 is capable of performing the motion of rotation4 ,moreover1 the hand being attached to the radius through the medium of the wrist 7figs4 ,,lxxxii4 #a4 #d4 and ,,lxxxiii4 #a4 #d7 must necessarily follow every movement of the radius2 the rotation of which brings the hand into two opposite positions4 ,in the one1 the palm of the hand is directed upwards 7fig4 ,,lxxxii472 in the other1 it is turned downwards 7fig4 ,,lxxxiii474 ,when the hand is turned upwards1 it is said to be in the state of supination 7fig4 ,,lxxxii472 when downwards1 in that of pronation 7fig4 ,,lxxxiii474 ,a distinct apparatus of muscles is provided for effecting the rotation of the radius1 in order to bring the hand into these opposite states3 one set for producing its supination1 and another its pronation4 #afh4 ,the principal supinators arise from the external condyle of the humerus 7fig4 ,,lxxx471 and are called long and short 7fig4 ,,lxxx4 #d1 #e74 ,the long supinator extends as far as the lower end of the radius1 into which it is inserted 7fig4 ,,lxxx4 #d73 the short supinator surrounds the upper part of the radius1 and is attached to it in this situation 7fig4 ,,lxxx4 #e474 ,moreover1 the triceps1 being inserted into the radius 7#afd71 often cooperates with the supinators and powerfully assists their action4 #afi4 ,the principal pronators are also two1 called the round and the square 7figs4 ,,lxxxi4 and ,,lxxxvi4 #a74 ,the round pronator arises from the internal condyle1 and passing downwards1 is inserted into the middle of the radius 7fig4 ,,lxxxi4 #d72 the square pronator is a small muscle between the radius and ulna1 at their lower extremities being attached to each 7fig4 ,,lxxxvi4 #a74 ,illustration3 ,fig4 ,,lxxx4 ,view of the supinators of the radius and hand4 #a4 ,the humerus2 #b4 the ulna2 #c4 the radius2 #d4 the muscle called the long supinator passing to be inserted into the lower portion of the radius2 #e4 the muscle1 called the short supinator1 surrounding the upper part of the radius4 #agj4 ,the action of these muscles in producing the rotation of the radius1 and so rendering the hand supine or prone1 is sufficiently manifest from the mere inspection of the diagrams 7fig4 ,,lxxxi4 #d74 ,illustration3 ,fig4 ,,lxxxi4 ,view of the pronators of the hand4 #a4 ,lower end of the humerus2 #b4 the radius2 #c4 the ulna2 #d4 the muscle called the round pronator1 one of the powerful pronators of the hand4 #aga4 ,the hand is composed of the carpus1 metacarpus1 and fingers4 #agb4 ,the carpus 7fig4 ,,lxxxii4 #d7 consists of eight small wedge-shaped bones1 placed in a double row1 each row containing an equal number1 and the whole disposed like stones in an arch 7fig4 ,,lxxxii4 #d74 ,they do in fact form an arch1 the convexity of which is upwards1 on the dorsal surface 7fig4 ,,lxxxiii4 #d72 and the concavity downwards1 on the palmar surface 7fig4 ,,lxxxii4 #d74 ,but they differ from the stones of an arch in this1 that each bone is joined to its fellow by a distinct moveable joint1 each being covered with a smooth articulating cartilage4 ,at the same time all of them are tied together by ligaments of prodigious strength1 which cross each other in every direction 7fig4 ,,lxxvii4 #f71 so that the several separate joints are consolidated into one great joint4 ,the consequence of this mechanism is that some degree of motion is capable of taking place between the several bones1 which1 when multiplied together1 gives to the two rows of bones such an extent of motion1 that when the wrist is bent the arch of the carpus forms a kind of knuckle4 ,by this construction a facility and ease of motion1 and a power of accommodation to motion and force1 are obtained1 such as belong to no arch contrived by human ingenuity4 ,illustration3 ,fig4 ,,lxxxii4 #a4 ,lower extremity of the radius2 #b4 lower extremity of the ulna2 #c4 styloid process of the ulna2 #d4 bones of the carpus or wrist2 #e4 metacarpal bones2 #f4 first phalanges of the fingers2 #g4 second phalanges of the fingers2 #h4 third phalanges of the fingers4 #agc4 ,the metacarpus 7fig4 ,,lxxxii4 #e71 the middle portion of the hand1 interposed between the wrist and the fingers1 is composed of five bones1 which are placed parallel to each other 7fig4 ,,lxxxii4 #e74 ,they are convex outwardly1 forming the back 7fig4 ,,lxxxiii4 #e71 and concave inwardly1 forming the hollow of the hand 7fig4 ,,lxxxii4 #e74 ,they are large at each end1 to form the joints by which they are connected with the wrist and fingers 7figs4 ,,lxxxii4 and ,,lxxxiii473 they are small in the middle1 in order to afford room for the lodgment and arrangement of the muscles1 that move the fingers from side to side 7fig4 ,,lxxxvi4 #b74 ,their ends1 which are joined to the carpus1 are connected by nearly plane surfaces 7figs4 ,,lxxxii4 and ,,lxxxiii473 their ends1 which support the fingers1 are formed into rounded heads1 which are received into corresponding cup-shaped cavities1 excavated in the top of the first bones of the fingers 7fig4 ,,lxxxii4 #e474 ,the powerful ligaments that unite these bones pass1 both on the dorsal and the palmar surface1 from the inferior extremity of the second row of the carpal to the bases of the metacarpal bones 7fig4 ,,lxxvii1 #g1 #h74 ,the ligaments are arranged in such a manner as to limit the motions of the joints chiefly to those of flexion and extension1 allowing1 however1 a slight degree of motion from side to side4 #agd4 ,each of the fingers is composed of three separate pieces of bone1 called phalanges2 the thumb has only two 7fig4 ,,lxxxii4 #f1 #g1 #h73 the phalanges are convex outwardly 7fig4 ,,lxxxii4 #f1 #g1 #h7 for increasing their strength1 and flattened inwardly 7fig4 ,,lxxxiii4 #f1 #g1 #h7 for the convenience of grasping4 ,the last bones of the fingers1 which are small1 terminate at their under ends1 in a somewhat rounded and rough surface 7fig4 ,,lxxxiii4 #h71 on which rests the vascular1 pulpy1 and nervous substance1 constituting the special organ of touch1 placed at the points of the fingers1 and guarded on the upper surface by the nail 7fig4 ,,lxxxii4 #h74 ,illustration3 ,fig4 ,,lxxxiii4 #a4 ,lower extremity of the radius2 #b4 lower extremity of the ulna2 #c4 styloid process of the ulna2 #d4 bones of the carpus2 #e4 metacarpal bones2 #f4 #g4 #h4 first1 second1 and third phalanges of the fingers4 #age4 ,the round inferior extremity of the metacarpus is admitted into the cavity of the superior extremity of the first phalanx of the five fingers 7figs4 ,,lxxxii4 and ,,lxxxiii471 and their joints are connected by lateral and transverse ligaments of great strength 7fig4 ,,lxxvii4 #i74 ,the situation and direction of the ligaments which unite the several phalanges of the fingers 7fig4 ,,lxxvii4 #i7 are precisely the same as those of the articulation of the phalanges with the metacarpus 7fig4 ,,lxxvii4 #g1 #h72 and the articulation of these bones with one another is such as to admit only of the motions of flexion and extension4 #agf4 ,the muscles which perform these motions are seated for the most part on the fore-arm4 ,independently of the supinators and pronators which have been already described 7#afg et seq471 there are distinct sets of muscles for bending and extending the wrist and the fingers4 ,the flexors arise from the internal1 and the extensors from the external1 condyle of the humerus 7fig4 ,,lxix4 #c1 #d74 ,the internal condyle is larger and longer than the external 7fig4 ,,lxix4 #c1 #d72 for the flexors require a larger point of origin and a longer fulcrum than the extensor muscles2 because to the actions of flexion1 such as grasping1 bending1 pulling1 more power is necessary than to the action of extension1 which consists merely in the unfolding or the opening of the hand previously to the renewal of the grasp4 #agg4 ,for the same reason1 two muscles are provided for flexing1 while only one is provided for extending the fingers4 ,the flexors1 bulky1 thick1 and strong1 are placed on the fore part of the fore-arm 7fig4 ,,lxxxiv474 ,the first1 named the superficial flexor 7fig4 ,,lxxxiv4 #a71 about the middle of the arm1 divides into four fleshy portions1 each of which ends in a slender tendon 7fig4 ,,lxxxiv4 #a74 ,as these tendons approach the fingers they expand 7fig4 ,,lxxxiv4 #a71 and when in apposition with the first phalanx1 split and form distinct sheaths for the reception of the tendons of the second flexor 7fig4 ,,lxxxiv4 #c74 ,after completing the sheath1 the tendons proceed forward along the second phalanx1 into the fore part of which they are implanted1 and the chief office of this powerful muscle is to bend the second joint of the fingers upon the first1 and the first upon the metacarpal bone4 ,its action is assisted by a second muscle1 called the deep or profound flexor 7fig4 ,,lxxxiv4 #b71 because it lies beneath the former2 or the perforans1 because it pierces it4 ,bulky and fleshy1 this second flexor1 like the first1 about the middle of the arm1 divides into four tendons1 which1 entering the sheaths prepared for them in the former muscle 7where the tendons are small and rounded for their easy transmission and play71 pass to the root of the third phalanx of the fingers into which they are implanted 7fig4 ,,lxxxiv4 #c74 ,illustration3 ,fig4 ,,lxxxiv4 ,view of the flexor muscles of the fingers4 #a4 ,the superficial flexor1 divided and turned aside1 to show1 #b4 the deep flexor2 #c4 sheaths for the tendons of the deep flexor1 formed by the splitting of the tendons of the superficial flexor2 #d4 the anterior annular ligament1 divided and turned aside4 #aah4 ,the muscle that extends the fingers1 called the common extensor1 is placed on the back part of the fore-arm 7fig4 ,,lxxxv471 about the middle of which it divides into four portions which terminate in so many tendons 7fig4 ,,lxxxv4 #b74 ,when they reach the back of the metacarpal bones1 these tendons become broad and flat1 and send tendinous expansions to each other1 forming a strong tendinous sheath which surrounds the back of the fingers 7fig4 ,,lxxxv4 #b74 ,these tendinous expansions are inserted into the posterior part of the bones of the four fingers 7fig4 ,,lxxxv4 #b72 and their office is powerfully to extend all the joints of all the fingers 7fig4 ,,lxxxv4 #b74 #agi4 ,on both the palmar and dorsal regions of the wrist are placed ligaments for tying down these tendons1 and preventing them from starting from their situation during the action of the muscles 7figs4 ,,lxxxiv4 and ,,lxxxv474 ,on the palmar region an exceedingly strong ligament passes anteriorly to the concave arch of the carpus 7fig4 ,,lxxxiv4 #d7 for the purpose of tying down the tendons of the flexor muscles4 ,on the dorsal surface 7fig4 ,,lxxxv471 a similar ligament1 passing in an oblique direction from the styloid process of the radius to the styloid process of the ulna 7fig4 ,,lxxxv4 #c71 performs the same office in tying down the tendons of the extensor muscle4 ,both these ligaments are called annular4 ,illustration3 ,fig4 ,,lxxxv4 ,view of the extensor muscles of the fingers4 #a4 ,the common extensor1 sending 7#b #b #b #b7 tendons to each finger2 #c4 the posterior annular ligament4 #ahj4 ,in the palm of the hand are placed additional muscles which assist the flexors of the fingers 7fig4 ,,lxxxvi4 #b71 being chiefly useful in enabling the fingers to perform with strength and precision short and quick motions4 ,there are especially four small and rounded muscles 7fig4 ,,lxxxvi4 #b71 resembling the earth worm in form and size1 and hence called lumbricales2 but as their chief use is to assist the fingers in executing short and rapid motions1 they have also received the better name of the musculi fidicinales4 ,illustration3 ,fig4 ,,lxxxvi4 #a4 ,the muscle called the square pronator2 #b4 muscles seated in the palm of the hand1 by which1 chiefly1 the fingers execute short and rapid motions4 #aha4 ,the thumb1 in consequence of the comparative looseness of its ligaments1 is capable of a much greater extent of motion than the fingers1 and can be applied to any part of each of the fingers1 to different parts of the hand1 and in direct opposition to the power exerted by the whole of the fingers and hand1 in the act of grasping4 ,the muscles which enable it to perform these varied motions1 and which act powerfully in almost every thing we do with the hand1 form a mass of flesh at the ball of the thumb 7fig4 ,,lxxxvii4 #a71 almost entirely surrounding it4 ,the little finger is also provided with a distinct apparatus of muscles 7fig4 ,,lxxxvii4 #b71 which surrounds its root1 just as those of the thumb surround its ball1 in order to keep it firm in opposition to the power of the thumb in the act of grasping1 and in various other motions4 ,illustration3 ,fig4 ,,lxxxvii4 #a4 ,the mass of muscles forming the ball of the thumb2 #b4 the mass of muscles forming the ball of the little finger2 #c4 tendons of one of the flexor muscles of the fingers2 #d4 sheaths formed by the tendons of the superficial flexor for the reception of the tendons of the deep flexor4 #ahb4 ,the upper extremity is covered by a tendinous expansion or fascia which envelopes the whole arm1 encloses its muscles as in a sheath1 and affords them1 in their strong actions1 that kind of support which workmen feel in binding their arms with thongs4 ,this fascia likewise descends between many of the muscles1 forming strong partitions between them1 and affording points of origin to many of their fibres1 scarcely less fixed than bone itself4 #ahc4 ,from the whole1 it appears1 that the first joint of the upper extremities1 that of the shoulder1 is a ball and socket joint1 a joint admitting of motion in every direction2 that the second joint1 that of the elbow1 is partly a hinge-joint1 admitting of flexion and extension1 and partly a rotation joint1 admitting of a turning or rotatory motion2 and that the joints of the wrist and of the fingers are likewise hinge-joints1 admitting at the same time of some degree of lateral motion4 ,when these various motions are combined1 the result is that the hand can apply itself to bodies in almost every direction1 in any part of the area described by the arm1 when all the joints are moved to their utmost extent4 ,there is thus formed an instrument of considerable strength1 capable of a surprising variety and complexity of movements1 capable of seizing1 holding1 pulling1 pushing and striking with great power1 yet at the same time capable of apprehending the minutest objects1 and of guiding them with the utmost gentleness1 precision1 and accuracy1 so that there are few conceptions of the designing mind which cannot be executed by the skilful hand4 #ahd4 ,the lower extremities consist of the thigh1 leg1 and foot4 #ahe4 ,the osseous part of the thigh consists of a single bone1 called the femur 7fig4 ,,xxxiv4 #d71 the longest1 thickest1 and strongest bone in the body4 ,it sustains the entire weight of the trunk1 and occasionally much heavier loads superimposed upon it4 ,it is constructed in such a manner as to combine strength with lightness4 ,this is effected by rendering the bone what is technically called cylindrical2 that is1 a bone in which the osseous fibres are arranged around a hollow cylinder4 ,there are two varieties of osseous matter1--the compact1 in which the fibres are dense and solid 7fig4 ,,lxxxviii4 #a71 and the spongy1 in which the fibres are comparatively tender and delicate 7fig4 ,,lxxxviii4 #b74 ,both varieties are1 indeed1 combined1 more or less1 in every bone1 the compact substance being always external1 and the spongy internal2 but in the cylindrical bones the arrangement is peculiar4 ,every long or cylindrical bone consists of a body or shaft 7fig4 ,,lxxxviii4 #d471 and of two extremities 7fig4 ,,lxxxviii4 #e74 ,the body is composed principally of compact substance1 which on the external surface is so dense and solid1 that scarcely any distinct arrangement is visible2 but towards the interior this density diminishes2 the fibres become distinct 7fig4 ,,lxxxviii4 #e71 and form an expanded tissue of a cellular appearance 7fig4 ,,lxxxviii4 #e71 the cells being called cancelli1 and the structure cancellated4 ,in the centre of the bone even the cancelli disappear2 the osseous fibres terminate2 and a hollow space is left filled up1 in the natural state1 by an infinite number of minute membranous bags which contain the marrow 7fig4 ,,lxxxviii4 #c74 ,in the body of the bone1 to which strength is requisite1 that part being the most exposed to external violence1 the compact matter is arranged around a central cavity4 ,by this means strength is secured without any addition of weight2 for the resisting power of a cylindrical body increases in proportion to its diameter2 consequently the same number of osseous fibres placed around the circumference of a circle produce a stronger bone than could have been constructed had the fibres been consolidated in the centre1 and had the diameter been proportionally diminished4 ,the hollow space thus gained in its centre1 renders the bone lighter by the subtraction of the weight of as many fibres as would have gone to fill up that space2 while its strength is not only not diminished by this arrangement1 but positively increased4 ,on the other hand1 at the extremities of the bone1 space1 not strength1 is required2 required for the attachment and arrangement of the tendons of the muscles that act upon it1 and for the formation of joints 7fig4 ,,lxxxviii4 #e74 ,accordingly1 at its extremities the bone swells out into bulky surfaces2 but these surfaces are composed1 not of dense and solid substance1 but of spongy tissue1 covered by an exceedingly thin crust of compact matter1 and so1 as by the former expedient strength is secured without increase of weight1 by this1 space is obtained without increase of weight4 ,illustration3 ,fig4 ,,lxxxviii4 ,a section of the femur1 showing1 #a4 the compact bony substance2 #b4 the spongy or cancellated structure2 #c4 the internal cavity containing the marrow2 #d4 body2 #e1 extremities of the bone4 #ahf4 ,the thigh-bone1 placed at the under and outer part of the pelvis1 has an oblique direction1 the under being considerably nearer its fellow than the upper end 7fig4 ,,xxxiv4 #d71 in order to afford space for the passages at the bottom of the pelvis1 and also to favour the action of walking4 ,the body of the bone1 which is of a rounded form 7fig4 ,,xxxiv4 #d71 is smooth on its anterior surface 7fig4 ,,xxxiv4 #d71 where it is always slightly convex1 the convexity being forwards 7fig4 ,,xxxiv4 #d71 while its posterior surface is irregular and rough1 and forms a sharp prominent line1 termed the linea aspera 7fig4 ,,xxxv4 #d71 giving attachment to numerous muscles4 #ahg4 ,the superior extremity of the femur terminates in a large ball or head1 which forms nearly two-thirds of a sphere 7fig4 ,,lxxxix4 #d474 ,it is smooth1 covered with cartilage1 and received into the socket of the ilium called the acetabulum1 which1 deep as it is1 is still further deepened by the cartilage which borders the brim 7fig4 ,,lxxxix4 #c74 ,the brim is particularly high in the upper and outer part1 because it is in this direction that the reaction of the ground against the descending weight of the trunk tends to dislodge the ball from its socket4 #ahh4 ,passing obliquely downwards and outwards from the ball1 is that part of the femur which is called the neck 7fig4 ,,lxxxix4 #e74 ,it spreads out archlike between the head and the body of the bone1 and is more than an inch in length 7fig4 ,,lxxxix4 #e74 ,it is thus long in order that the head of the bone may be set deep in its socket1 and that its motions may be wide1 free1 and unembarrassed4 ,illustration3 ,fig4 ,,lxxxix4 #a4 ,lower portion of the ilium2 #b4 tuberosity of the ischium3 #c4 socket for the head of the femur1 or thigh-bone2 #d4 head of the femur2 #e4 neck of the femur2 #f4 the great process of the femur called the trochanter major2 #g4 the body of the femur4 #ahi4 ,from the external surface of the femur1 nearly in a line with its axis1 proceeds the largest and strongest bony process of the body which gives insertion to its most powerful muscles1 namely1 those that extend the thigh and that turn it upon its axis 7fig4 ,,lxxxix4 #f74 ,because1 from its oblique direction1 it rotates the thigh1 this process is called the trochanter1 and1 from its size1 the trochanter major4 ,at the under and inner part of the neck on the posterior surface of the bone1 is a similar process1 but much smaller1 called the trochanter minor 7fig4 ,,xxxv4 #d71 into which are inserted the muscles that bend the thigh4 #aij4 ,the inferior extremity of the femur1 much broader and thicker than the superior 7fig4 ,,xc4 #a71 is terminated by two eminences1 with smooth surfaces1 termed condyles 7fig4 ,,xc4 #b71 which1 articulated with the tibia1 and the patella1 form the joint of the knee 7figs4 ,,xc4 #b1 #d1 #e1 and ,,xci4 #a1 #b1 #c74 ,illustration3 ,fig4 ,,xc4 #a4 ,lower end of the femur2 #b4 condyles of the femur2 #c4 upper end of the tibia2 #d4 articular surfaces on the head of the tibia on which the thigh-bone plays2 #e4 the patella1 or knee-pan2 #f4 upper end of the fibula1 not entering into the knee-joint4 ,illustration3 ,fig4 ,,xci4 ,posterior view of the bones forming the knee-joint4 #a4 ,lower end of the femur2 #b4 upper end of the tibia2 #c4 articular surfaces on the head of the tibia1 on which the thigh-bone plays2 #d4 upper end of the fibula1 not entering into the knee joint4 #aia4 ,the bones of the leg1 two in number1 consist of the tibia 7fig4 ,,xc4 #c7 and fibula 7fig4 ,,xc4 #f74 ,the tibia1 next to the femur1 the longest bone in the body1 is situated at the inner side of the leg 7fig4 ,,xc4 #c74 ,its superior extremity is bulky and thick 7fig4 ,,xc4 #c74 ,the top of it forms two smooth and slightly concave surfaces1 adapted to the convex surfaces of the condyles of the femur 7fig4 ,,xc4 #d1 #b74 ,on its outer side there is a smooth surface1 to which the head of the fibula is attached 7fig4 ,,xc4 #f74 ,its lower extremity1 which is small1 forms a concavity adapted to the convexity of the bone of the tarsus1 called the astragalus1 with which it is articulated 7fig4 ,,xcii4 #d47 ,its inner part is produced so as to form the inner ankle 7figs4 ,,xcii4 #b1 and ,,xciii4 #c73 its outer side is excavated into a semilunar cavity1 for receiving the under end of the fibula1 which forms the outer ankle 7figs4 ,,xcii4 #c1 and ,,xciii4 #d74 #aib4 ,the fibula1 in proportion to its length the most slender bone of the body1 is situated at the outer side of the tibia 7fig4 ,,xc4 #f74 ,its upper end formed into a head1 with a flat surface on its inner side 7figs4 ,,xc4 #f1 and ,,xci4 #d71 is firmly united to the tibia 7fig4 ,,xc4 #d74 ,its lower end forms the outer ankle1 which is lower and farther back than the inner 7fig4 ,,xcii4 #c1 #b74 ,illustration3 ,fig4 ,,xcii4 ,anterior view of the bones forming the ankle-joint4 #a4 ,lower end of the tibia2 #b4 production of the tibia1 forming the inner ankle2 #c4 lower end of the fibula1 forming the outer ankle2 #d4 upper part of the astragalus3 these three bones form the ankle-joint2 #e #e #e1 other bones of the tarsus2 #f #f #f #f #f metatarsal bones4 ,illustration3 ,fig4 ,,xciii4 ,posterior view of the bones forming the ankle-joint4 #a4 ,lower end of the tibia2 #b4 lower end of the fibula2 #c4 internal malleolus or ankle2 #d4 external malleolus or ankle2 #e4 one of the tarsal bones1 called the astragalus1 with which the tibia and fibula are articulated2 #f4 the os calcis or heel4 #aic4 ,the patella1 or knee-pan 7fig4 ,,xc4 #e71 is a light but strong bone1 of the figure of the heart as painted on playing-cards1 placed at the fore part of the joint of the knee1 and attached by a strong ligament to the tibia1 the motions of which it follows 7fig4 ,,xc4 #e74 ,it is lodged1 when the knee is extended1 in a cavity formed for it in the femur 7fig4 ,,xc472 when bent1 in a cavity formed for it at the fore part of the knee 7fig4 ,,xc4 #e74 #aid4 ,the foot consists of the tarsus1 metatarsus1 and toes4 #aie4 ,the tarsus1 or instep1 is composed of seven strong1 irregular-shaped bones1 disposed like those of the carpus1 in a double row 7fig4 ,,xcii4 #d1 #e74 ,the arrangement of the tarsal bones is such as to form an arch1 the convexity of which above1 constitutes the upper surface of the instep 7fig4 ,,xcii4 #d1 #e73 in the concavity below are lodged the muscles1 vessels1 and nerves that belong to the sole4 #aif4 ,the metatarsus consists of five bones1 which are placed parallel to each other 7fig4 ,,xcii4 #f71 and which extend between the tarsus and the proper bones of the toes 7fig4 ,,xcii4 #f74 ,their extremities1 especially next the tarsus1 are large1 in order that they may form secure articulations with the tarsal bones 7fig4 ,,xcii4 #f74 ,their bodies are arched upwards 7fig4 ,,xcii4 #f71 slightly concave below1 and terminate forwards in small1 neat1 round heads1 which receive the first bones of the toes1 and with which they form joints1 admitting of a much greater degree of rotation than is ever actually exercised1 in consequence of the practice of wearing shoes4 ,the natural1 free1 wide-spreading form of the toes1 and the consequent security with which they grasp the ground1 is greatly impaired by this custom4 ,taken together1 the bones of the metatarsus form a second arch corresponding to that of the tarsus 7fig4 ,,xcviii4 #b74 #aig4 ,each toe consists of three distinct bones1 called1 like those of the fingers1 phalanges 7fig4 ,,xcviii471 but the great toe1 like the thumb1 has only two 7fig4 ,,xcviii474 ,that extremity of the first phalanges which is next the metatarsal bones is hollowed into a socket for the head of the metatarsal bones4 #aih4 ,besides the bones already described1 there are other small bones1 of the size and figure of flattened peas1 found in certain parts of the extremities1 never in the trunk1 called sesamoid1 from their resemblance to the seed of the sesamum4 ,they belong rather to the tendons of the muscles than to the bones of the skeleton4 ,they are embedded within the substance of tendons1 are found especially at the roots of the thumb and of the great toe1 and are always placed in the direction of flexion4 ,their office1 like that of the patella1 which is1 in truth1 a bone of this class1 is to increase the power of the flexor muscles by altering the line of their direction1 that is1 by removing them farther from the axis of the bone on which they are intended to act4 #aii4 ,the ligaments which connect the bones of the lower extremities are the firmest and strongest in the body4 ,of these1 the fibrous capsule of the hip-joint 7fig4 ,,xciv4 #a71 which secures the head of the femur in the cavity of the acetabulum 7fig4 ,,xciv471 is the thickest and strongest4 ,it completely surrounds the joint 7fig4 ,,xciv4 #a74 ,it arises from the whole circumference of the acetabulum1 and1 proceeding in a direction outwards and backwards1 is attached below to the neck of the femur 7fig4 ,,xciv4 #a74 ,it is thicker1 stronger1 and much more closely attached to the bones than the fibrous capsule of the shoulder-joint 7#add71 because the hip-joint is formed1 not like the shoulder-joint1 for extent of motion1 but for strength4 ,its internal surface is lined by synovial membrane1 and its external surface is covered and strengthened by the insertion of muscles that move the thigh-bone4 ,the joint is strengthened by another ligament1 which passes from the inner and fore part of the cavity of the acetabulum 7fig4 ,,xcv47 to be inserted into the head of the femur 7fig4 ,,xciv471 called the round ligament1 the office of which obviously is to hold the head of the femur firmly in its socket4 ,illustration3 ,fig4 ,,xciv4 #a4 ,the fibrous capsule of the hip-joint1 laid open and turned aside to show1 #b4 the round ligament in its natural position4 ,illustration3 ,fig4 ,,xcv4 ,a view of the head of the femur drawn out of its socket1 and suspended by the round ligament1 to show more clearly the action of the ligament in retaining the head of the femur in its socket4 #bjj4 ,numerous and complicated ligaments connect the bones that form the knee-joint 7fig4 ,,xcvi471 and the strength of these powerful bands is greatly increased by the tendons that move the leg 7fig4 ,,xcvi4 #e71 which pass over1 and more or less surround1 the joint4 ,illustration3 ,fig4 ,,xcvi4 ,general view of the ligaments of the knee-joint4 #a4 ,lower end of the femur2 #b4 upper end of the tibia2 #c4 upper end of the fibula2 #d4 the patella2 #e4 united tendons of the extensor muscles2 #f4 ligaments of the patella2 #g4 the capsular investment of the knee2 #h4 the internal lateral ligament2 #i4 the external lateral ligaments2 #aj4 the posterior ligament2 #aa4 the ligament connecting the tibia and fibula2 #ab4 a portion of the interosseous ligament4 #bja4 ,strong ligaments maintain in their proper position the bones that form the ankle-joint 7fig4 ,,xcvii471 connect the bones of the tarsus and metatarsus with one another 7fig4 ,,xcviii4 #a71 and articulate the several phalanges of the toes 7fig4 ,,xcviii4 #b74 ,illustration3 ,fig4 ,,xcvii4 ,general view of the posterior ligaments of the ankle-joint4 #a4 ,lower end of the tibia2 #b4 lower end of the fibula2 #c4 astragalus2 #d4 os calcis2 #e4 ligament between the tibia and fibula2 #f4 ligament passing from the fibula to the astragalus2 #g4 ligament passing from the fibula to the os calcis2 #h4 ligament passing from the tibia to the astragalus4 ,illustration3 ,fig4 ,,xcviii4 ,general view of the ligaments of the sole of the foot4 #a4 ,ligaments connecting the bones of the tarsus2 #b4 ligaments connecting the bones of the toes4 #bjb4 ,the joint of the hip1 like that of the shoulder1 is capable of flexion1 extension1 and rotation2 but its rotatory motions are to a much less extent1 on account of the greater depth of the acetabulum and the stronger and shorter fibrous capsule4 ,when the femur is flexed1 the thigh is bent upon the pelvis1 and its inferior extremity is carried forwards4 ,when it is extended1 the thigh is carried backwards4 ,the two thighs may be separated from each other laterally 7abduction71 or brought near to each other 7adduction71 or the one may be made to cross the other1 and they may be rotated outwards or inwards4 #bjc4 ,the apparatus of muscles that produces these varied motions is seated partly on the trunk and partly on the pelvis4 ,thus1 the powerful muscle that flexes the thigh1 or that carries it forwards1 termed the psoas 7fig4 ,,xcix4 #a71 arises from the last vertebra of the back1 and successively from each vertebra of the loins 7fig4 ,,xcix4 #a71 and is inserted into the lesser trochanter of the femur 7fig4 ,,xcix4 #c74 ,its action is assisted first by a large and strong muscle named the iliacus 7fig4 ,,xcix4 #b71 which occupies the whole concavity of the ilium 7fig4 ,,xcix4 #b71 and which1 like the psoas1 is inserted into the lesser trochanter of the femur 7fig4 ,,xcix4 #c74 ,illustration3 ,fig4 ,,xcix4 ,view of the muscles that bend the thigh4 #a4 ,the muscle called psoas2 #b4 the muscle called iliacus2 #c4 tendons of these muscles1 going to be inserted into the trochanter minor of the femur4 #bjd4 ,the muscles that extend the thigh1 or that carry it backwards1 named the gluti1 the most powerful muscles of the body1 are placed in successive layers1 one upon the other1 on the back part of the ilium 7fig4 ,c4 #a1 #b1 #c71 and are inserted into the linea aspera of the femur4 ,they constitute the mass of flesh which forms the hip1 and their powerful action in drawing the thigh backwards is assisted by several other muscles 7fig4 ,c4 #d1 #e1 #f74 ,their action is never perfectly simple and direct2 for those which move the thigh forwards sometimes carry it inwards1 and sometimes outwards2 and in like manner1 those which move it backwards1 at one time carry it inwards and at another outwards1 according to the direction of the fibres of the muscle and the position of the limb when those fibres act2 while some of them1 and more especially those which carry it backwards1 at the same time rotate it1 or roll it upon its axis4 ,illustration3 ,fig4 ,c4 ,view of the muscles that extend the thigh4 #a4 ,the muscle called glutus maximus1 removed from its origin1 #b1 #b1 to show the muscles which lie beneath it2 #b4 cut edge showing the origin of the same muscle2 #c4 the muscle called glutus medius2 #d1 #e1 #f4 smaller muscles1 assisting the action of the gluti4 #bje4 ,the knee is a hinge-joint1 admitting only of flexion and extension1 and is therefore provided only with two sets of muscles1 one for bending and the other for extending the leg4 ,the flexors of the leg arise from the under and back part of the pelvis1 are seated on the back part of the thigh1 and are inserted into the upper part either of the tibia or of the fibula 7fig4 ,,ci74 ,they consist for the most part of three muscles1 named the semi-tendinosus1 the semi-membranosus 7fig4 ,,ci4 #c71 and the biceps of the leg 7fig4 ,,ci4 #a74 ,the tendons of the two former muscles1 in passing to be inserted into the leg1 form the inner1 and that of the latter the outer1 hamstrings 7fig4 ,,ci4 #d1 #e74 ,illustration3 ,fig4 ,,cii4 ,view of the flexor and extensor muscles of the leg4 #a4 ,the biceps of the leg2 #b4 tendon of the biceps1 inserted into the head of the fibula2 #c4 the semi-membranosus1 passing to be inserted into the head of the fibula2 #d4 tendon of the semi-membranosus forming the inner1 and #e4 tendon of the biceps forming the outer1 hamstring2 #f4 upper part of the gastrocnemius muscle2 #g4 the four large muscles which unite to form the great extensor muscle of the leg1 inserted into #h4 the patella2 #i4 a portion of the glutus maximus concealing the other muscles of the hip4 #bjf4 ,four large muscles1 blended together in such a manner as to form one muscle of prodigious size1 termed the quadriceps cruris 7fig4 ,,ci4 #g71 occupying nearly all the forepart and the sides1 and a considerable portion of the back part of the thigh1 constitute the great flexor of the thigh4 ,this enormous mass of muscle arises partly from the ischium1 and partly from the upper part of the femur 7fig4 ,,ci4 #g71 and is all inserted into the patella 7fig4 ,,ci4 #h71 which constitutes a pulley for the purpose of assisting the action of these powerful muscles4 #bjg4 ,the muscles which bend the toes and extend the foot1 termed the gastrocnemii 7fig4 ,,cii4 #a1 #b71 are placed on the back part of the leg1 and form the mass of muscle which constitutes the calf of the leg 7fig4 ,,cii4 #a1 #b74 ,they arise partly from the lower extremity of the femur 7fig4 ,,cii47 and partly from the upper and back part of the fibula and tibia2 and they form the largest and strongest tendon in the body1 termed the tendo achillis 7fig4 ,,cii4 #c71 which is implanted into the heel 7fig4 ,,cii4 #d74 ,illustration3 ,fig4 ,,cii4 ,view of the muscles which bend the toes1 and which1 by lifting the heel1 extend the foot4 #a4 ,the muscle called gastrocnemius externus1 which1 uniting with #b4 the gastrocnemius internus1 forms #c4 the tendo achillis1 which is inserted into #d4 the heel4 ,illustration3 ,fig4 ,,ciii4 ,view of the muscles which extend the toes and bend the foot4 #a4 ,the common extensor2 #b4 the tendons of the same muscle inserted into the toes2 #c4 the anterior annular ligament of the foot4 ,illustration3 ,fig4 ,,civ4 ,view of the muscles in the sole of the foot4 #a ,the muscle which draws the great toe from the other toes2 #b4 the muscle which draws the little toe from the other toes2 #c4 the muscle called the short flexor of the toes1 which assists in bending the four smaller toes4 #bjh4 ,the muscles which extend the toes and bend the foot are seated on the fore part of the leg 7fig4 ,,ciii472 split into tendons like the analogous muscles of the fingers 7fig4 ,,ciii4 #b72 and are bound down by a ligament 7fig4 ,,ciii4 #c71 exactly the same in name1 disposition1 and office1 as that which belongs to the hand 7fig4 ,,ciii4 #c74 ,numerous minute muscles are placed in the sole of the foot 7fig4 ,,civ471 which act on the toes as the small muscles in the palm of the hand act on the fingers 7fig4 ,,lxxxvi474 #bji4 ,such are the moving powers which put in action the complicated mechanism provided for the function of locomotion4 ,and these powers are adequate to their office2 but they are what may be termed expensive powers2 agents requiring a high degree1 of organization and the utmost resources of the economy to support and maintain them4 ,hence in the construction of the framework of the machine which they have to move1 whatever mechanical contrivance may economize their labour1 is adopted4 ,the construction1 form1 and disposition of the several parts of that framework have all reference to two objects3 first1 the combination of strength with lightness2 and secondly1 security to tender organs1 with the power of executing rapid1 energetic1 and1 sometimes1 violent motions4 ,the combination is effected and the object attained in a mode complicated in the detail1 simple in the design1 and perfect in the result4 ,the weight of the body transmitted from the arch of the pelvis to a second arch1 formed by the neck of the thigh-bone1 and from this1 in a perpendicular direction1 to a third arch formed by the foot1 is ultimately received by the heel behind1 and by the metatarsal bones and the first phalanges of the toes before1 and more especially by the metatarsal joints belonging to the great and little toe1 which have a special apparatus of muscles1 for the purpose of preserving steadily their relative situation to the heel4 ,the weight of the body is thus sustained on a series of arches1 from which it is1 in succession1 transmitted to the ground1 where it ultimately rests upon a tripod3 forms known and selected as the best adapted to afford support1 and to give security of position4 ,columns of compact bone superimposed one upon another1 and united at different points by bands of prodigious strength1 form the pillars of support4 ,but these bony columns never touch each other2 are never in actual contact2 are all separated by layers of elastic matter which1 while they assist in binding the columns together1 enable them to move one upon another1 as upon so many pliant springs4 ,the layers of cartilage interposed between the several vertebr2 the layer of cartilage interposed between the vertebral column and the pelvis2 the layer of cartilage that lines the acetabulum and that covers the head of the femur2 the layer of cartilage that covers the lower extremity of the femur and the upper extremity of the tibia and fibula and the tarsus2 the successive layers of cartilage interposed between the several bones of the tarsus2 and finally1 the layer of cartilage that covers both the tarsal and the digital extremities of the metatarsal bones2 are so many special provisions to prevent the weight of the body from being transmitted to the ground with a shock2 and1 at the same time1 so many barriers established between the ground and the spinal cord1 the brain and the soft and tender organs contained in the thoracic and abdominal cavities1 to prevent these organs from being injured by the reaction of the ground upon the body4 ,the excellence of this mechanism is seen in its results2 in contemplating from what heights we can leap--to what heights we can spring--to what distances we can bound--how swiftly we can run--how firmly we can stand--how nimbly we can dance--and yet how perfectly we can balance ourselves upon the smallest surfaces of support6 #baj4 ,it is necessary1 in order to complete this general view of the structure of the human body1 and of the combination and arrangement of its various parts1 to denote the several regions into which1 for the purpose of describing with accuracy the situation and relation of its more important organs1 the body is divided4 ,it is not needful to the present purpose to describe the regions of the head1 because its internal cavity contains only one organ1 the brain1 and its external divisions do not differ materially from those which are common and familiar2 but the chest1 the abdomen1 and the upper and lower extremities are mapped out into regions1 of which it is very important to have an exact knowledge1 which may be acquired by the study of the annexed diagrams4 ,illustration3 ,fig4 ,,cv4 ,anterior view of the regions of the body4 #a4 ,region of the neck2 #b4 region of the chest or thorax4 ,abdominal regions3 #c4 epigastric2 #d4 umbilical2 #e4 hypogastric region4 ,regions of the upper extremities4 #f4 shoulder2 #g4 arm2 #h4 elbow2 #i4 fore-arm2 #aj4 wrist2 #aa4 ball of thumb2 #ab4 the axilla or armpit4 ,regions of the lower extremities3 #ac4 thigh2 #ad4 knee2 #ae4 leg2 #af4 ankle2 #ag4 instep and foot4 ,illustration3 ,fig4 ,,cvi4 ,posterior view of the regions of the body3 #ah4 region to the scapula2 #ai4 of the back2 #bj4 of the loins2 #ba4 of the hips2 #bb4 of the ham2 #bc4 of the calf of the leg2 #bd4 of the heel and foot4 ,illustration3 ,fig4 ,,cvii4 ,lateral view of the regions of the body3 #be4 arch of the foot4 ,illustration3 ,fig4 ,,cviii4 ,anterior view of the situation of the more important internal organs3 #a4 lungs1 right and left2 #b4 heart2 #c4 line representing the edge of the diaphragm2 #d4 liver2 #e4 stomach2 #f4 small intestines2 #g4 colon2 #h4 urinary bladder4 ,illustration3 ,fig4 ,,cix4 ,posterior view of the situation of the more important internal organs3 #i4 kidnies1 right and left2 #aj4 the course of the spinal cord4 ,illustration3 ,fig4 ,,cx4 ,lateral view of the situation of the more important internal organs4 ,,chapter ,,vi4 ,,of ,,the ,,blood4 ,physical characters of the blood3 colour1 fluidity1 specific gravity1 temperature3 quantity--,process of coagulation--,constituents of the blood3 proportions--,constituents of the body contained in the blood--,vital properties of the blood--,practical applications4 #baa4 ,supposing the human body to have been built up in the manner now described1 and to be in the full exercise of all its functions1 the integrity of its various structures is maintained1 and their due action excited by the blood4 ,out of this substance is formed the blandest fluid1 as the milk1 and the firmest solid1 as the compact bone4 ,the heart1 capable of untiring action1 as long as the blood is in contact with its internal surface1 becomes immovable soon after the supply of this fluid is withdrawn2 and in less than one minute from the time it ceases to flow in due quantity and of proper quality through the vessels of the brain1 the eye is no longer capable of seeing1 nor the ear of hearing1 nor the brain of carrying on any intellectual operation4 #bab4 ,at the moment1 and for some time after it has issued from its vessel1 the appearance of the blood is that of a thick1 viscid1 and tenacious fluid2 yet it is essentially a solid1 composed of several substances1 each possessing its own distinct and peculiar properties1 the relation and combination of which cannot be considered without exciting the feeling that our admiration of the structure of the animal frame ought not to be confined to the mechanism of its solid parts1 but that the whole is admirable1 from the common material of which it is composed1 to its most delicate and elaborate instrument4 #bac4 ,the colour of redness is universally associated with the idea of blood2 but redness of colour is not essential to blood4 ,there are many animals with true1 yet without red1 blood2 and there is no animal in which the blood is red in all the parts of its body4 ,the blood of the insect is transparent2 that of the reptile is of a yellowish colour2 that of the fish1 in the greater part of its body1 is colourless4 ,even the red blood of the human body is not equally red in every part of it1 there being two distinct systems of blood-vessels1 distinguished from each other by carrying blood of different colours4 #bad4 ,in the state of health1 the specific gravity of human blood1 water being #ajjj1 is #ajhj2 from which standard it is capable of varying from #aabj1 the maximum1 to #ajbf1 the minimum4 #bae4 ,the natural temperature of the human blood is #ih4 ,from this it is capable of varying from #ajd1 the maximum1 to #hf1 the minimum2 these changes being always the effect of disease4 #baf4 ,it is estimated that the fluids circulating in the adult man amount to about fifty pounds2 of these it is calculated that twenty-eight consist of red blood4 #bag4 ,fluid and homogeneous as the blood appears while flowing in its vessel1 when a mass of it is collected and allowed to stand at rest1 it soon undergoes a very remarkable change4 ,first1 a thin film is formed upon its surface2 this is followed by the conversion of the whole mass into a soft jelly3 this jelly separates into two portions1 a fluid and a solid portion4 ,the solid portion again separates into two parts1 into a substance of a yellowish-white colour1 occupying the upper surface1 and into a red mass always found at the under surface4 #bah4 ,the process by which the constituents of the blood are thus spontaneously disunited1 and afforded in a separate form1 is denominated ,,coagulation2 the fluid portion separated by the process is termed the ,,serum2 the solid portion the ,,coagulum or ,,clot2 the white substance forming the upper part of the clot1 the ,,fibrin2 and the red mass forming the under part of it1 the ,,red ,,particles4 #bai4 ,probably the process of coagulation commences the moment the blood leaves its living vessel4 ,in three minutes and a half it is visible to the eye2 in seven minutes the mass is formed into a jelly2 in from ten to twelve minutes the serum separates from the clot2 in about twenty the clot is divided into fibrin and red particles1 when the coagulation is complete2 but occasionally the clot continues to grow firmer and firmer for the space of twenty-four hours4 #bbj4 ,as soon as the coagulation commences1 and during all the time the blood preserves its heat1 an aqueous vapour arises from it1 termed the ,,halitus4 ,the halitus consists of water holding in solution a small quantity of animal and saline matter1 which communicate to it a ftid odour of a strong and peculiar nature1 manifest on approaching a slaughter-house1 and still more manifest in the slaughter-house of human beings1 a field of battle4 #bba4 ,during the process of coagulation1 as in every other in which a fluid is converted into a solid1 caloric is evolved4 #bbb4 ,during the process of coagulation carbonic acid is also extricated4 #bbc4 ,the process of coagulation affords three distinct substances1 the chief constituents of the blood1 namely1 serum1 fibrin1 and red particles4 #bbd4 ,the serum1 the fluid portion of the blood1 when obtained perfectly pure1 is of a light straw colour1 tinged with green4 ,its taste is saline1 and its consistence adhesive4 ,it is composed principally of water holding in solution animal and saline matter4 ,the animal matter gives it its adhesive consistence1 and the saline its peculiar salt taste4 ,the chief animal matter contained in it is the proximate principle termed albumen1 which may be separated from the water that holds it in solution by the application of heat and by certain chemical agents4 ,heat being applied1 when the temperature reaches #afj1 fluid serum is converted into a white opaque solid substance of firm consistence4 ,this is found to be albumen1 which may be also separated from the watery portion by the application of spirits of wine1 acids1 oxymuriate of mercury1 and several other chemical substances4 ,the quantity of albumen contained in #ajjj parts of serum varies from about #gh1 the maximum1 to #eh1 the minimum4 #bbe4 ,if the albumen yielded by the serum be subjected to pressure1 or be cut into small pieces1 there flows from it a watery fluid which is termed the serosity4 ,in meat dressed for the table1 the serum of the blood contained in the blood-vessels is converted by the heat into solid albumen1 from which1 when cut1 the serosity flows in the form of gravy4 #bbf4 ,besides albumen1 serum holds in solution both a fatty and an oily matter1 in the proportion of about one part of each to #ajjj parts of serum4 ,the proportion of its saline substances is about ten in #ajjj parts4 ,according to ,m4 le ,canu1 who has made the most recent chemical analysis of serum1 #ajjj parts contain1 of ,water #ijfjj ,albumen #ghjj ,animal matter1 soluble in water and alcohol #afi ,albumen combined with soda #baj ,crystallizable fatty matter #abj ,oily matter #ajj ,hydrochlorate of soda and potash #fjj ,subcarbonate and phosphate of soda1 and sulphate of potash #baj ,phosphate of lime1 magnesia1 and iron1 with subcarbonate of lime and magnesia #ia ,loss #ajj #bbg4 ,all the animal and saline matter held in solution in the serum being removed1 the fluid that remains is water1 the proportion of which in #ajjj parts varies from #hec1 the maximum1 to #ggi1 the minimum4 #bbh4 ,the second constituent of the blood1 the fibrin1 is the most essential portion of it1 being invariably present1 whatever other constituent be absent4 ,while circulating in the living vessel1 fibrin is fluid and transparent2 by the process of coagulation1 it is converted into a solid and opaque substance of a yellowish white colour1 consisting of stringy fibres1 disposed in stri1 which occasionally form a complete net-work 7fig4 ,,cxi474 ,these fibres are exceedingly elastic4 ,in their general aspect and their chemical relations they bear a close resemblance to pure muscular fibre1 that is1 to muscular fibre deprived of its enveloping membrane and of its colouring matter1 and they form the basis of muscle4 ,according to ,m4 le ,canu1 the proportion of the fibrin varies from seven parts in #ajjj1 the maximum1 to one part in #ajjj1 the minimum1 the medium of twenty experiments being four parts in #ajjj4 ,illustration3 ,fig4 ,,cxi4 ,a portion of the fibrin of the blood1 showing its fibrous structure and the striated or net-like arrangement of its fibres4 #bbi4 ,the third constituent of the blood1 the matter upon which its red colour depends1 though1 as has been stated1 entirely absent in certain classes of animals1 and in all animals in some parts of their body1 seems to be essential1 at least to the organic organs1 whenever they perform their functions with a high degree of perfection4 ,thus in the lowest class of vertebrated animals1 the fish1 while the principal part of its body receives only a colourless fluid1 its organic organs1 as the heart1 the gills1 the liver1 are provided with red blood4 #bcj4 ,the red matter1 wherever present1 is invariably heavier than the fibrin1 and consequently1 during the process of coagulation1 it gradually subsides to the lower surface1 and is always found forming the bottom of the clot4 ,its proportion to the other constituents varies very remarkably1 the maximum being #adh1 the minimum #fh1 and the medium #ajh1 in #ajjj parts of blood4 #bca4 ,all observers are agreed that the red matter of the blood consists of minute particles1 having a peculiar and definite structure2 but in regard to the nature of that structure1 there is considerable diversity of opinion1 which is not wonderful1 since the particles in question are so minute that they can be distinguished only by the microscope1 and since1 of all microscopical objects1 they are perhaps the most difficult to examine1 because1 being soft and yielding1 their figure is apt to change1 and because there is reason to suppose that their substance is not uniform in its refractive power4 #bcb4 ,the earlier observers describe the red particles as being of a globular figure1 and accordingly name them globules4 ,they conceive that each globule consists of a central solid particle1 enveloped in a transparent vesicle4 ,recently1 ,sir ,everard ,home and ,mr4 ,bauer in this country1 and ,,mm4 ,prevost and ,dumas on the continent1 have revived this opinion1 and describe the red particle as consisting of a central solid white corpuscle contained in an external envelop of a red colour4 ,when the blood is observed with the microscope in a living animal1 flowing in its vessels1 only two substances can be distinguished1 namely1 a transparent fluid and the red corpuscles4 ,,mm4 ,prevost and ,dumas contend that these two substances are the only component parts of the blood4 ,when the blood coagulates1 they conceive that the red envelop separates from the central white corpuscle2 that these white corpuscles unite together2 that the aggregates resulting from this combination are disposed in the form of filaments1 which filaments constitute the fibrin1 while the red matter at the bottom of the clot is nothing but the disintegrated envelops of the central particle4 ,but this view is not the common one4 ,in general1 physiologists conceive the fibrin to be one constituent and the red particles to be another constituent of the blood4 ,mr4 ,lister1 who has successfully laboured to improve the microscope1 and who1 together with his friend ,dr4 ,hodgkin1 have very carefully examined with their improved instrument the red particles1 contend that the figure of these bodies is not globular1 although they state that the instant the particles are removed from the living blood-vessels many things are capable of making them assume a globular appearance2 such1 for example1 as the application of water4 ,with a rapidity which1 in spite of every precaution1 the eye in vain attempts to follow1 the particles change their real figure for a globular form on the application of the smallest quantity of pure water2 while1 if the water contain a solution of saline matter1 little alteration is occasioned in the figure of the particles4 ,according to these observers1 the red particles are flattened cakes1 having rounded and very slightly thickened margins 7fig4 ,,cxii4 #a74 ,the thickness of the margin gives to both surfaces the appearance of a slight depression in the middle 7fig4 ,,cxii4 #a71 so that the particles bear a close resemblance to a penny piece4 ,there is no appearance of an external envelop4 ,the circular and flattened cake is transparent2 when seen singly it is nearly if not quite colourless 7fig4 ,,cxii4 #a72 it assumes a reddish tinge only when aggregated in considerable masses4 ,illustration3 ,fig4 ,,cxii4 #a4 ,a particle of the human blood as it appears when transparent and floating2 #b4 the same dry1 seen as opaque1 illuminated by a leiberkuhn2 #c4 the same as it appears when half the leiberkuhn is darkened2 #d4 a particle of the frog's blood floating2 #e4 the same seen on its edge4 ,all the above objects are magnified #ejj diameters#e4 #bcc4 ,the red particle of the human blood is circular 7fig4 ,,cxii4 #a1 #b1 #c74 ,it is circular also in all animals belonging to the class mammalia2 but in the three lower classes of vertebrated animals1 the bird1 the reptile1 and the fish1 it is elliptical 7fig4 ,,cxii4 #d1 #e74 #bcd4 ,the magnitude of the red particle of the human blood is variously estimated from the two-thousandth to the six-thousandth part of an inch in diameter4 ,bauer estimates it at the two-thousandth1 ,hodgkin and ,lister at the three-thousandth1 ,kater at the four-thousandth1 ,wollaston at the five-thousandth1 and ,young at the six-thousandth part of an inch4 ,its magnitude is uniformly the same in all individuals of the same species1 but differs exceedingly in the different classes4 ,the elliptical particles are larger than the circular1 but proportionally thinner2 larger in fishes than in any other class of animals1 and largest of all in the skate4 #bce4 ,when perfect and entire1 the red particles indicate a disposition to arrange themselves in a definite mode4 ,they combine spontaneously into columns of variable length 7fig4 ,,cxiii474 ,in order to observe this tendency1 a small quantity of blood1 the moment it is taken from its living vessel1 should be placed between two strips of glass or covered with a bit of talc and placed under the microscope4 ,when thus arranged1 a considerable agitation at first takes place among the particles4 ,as soon as this motion subsides1 the particles apply themselves to each other by their broad surfaces1 and thus form piles or columns of ,considerable length 7fig4 ,,cxiii474 ,the columns often again combine one among another1 the end of one being attached to the side of another1 sometimes producing very curious ramifications 7fig4 ,,cxiii474 ,in like manner1 the elliptical particles apply themselves to each other by their broad surfaces1 but they are not so exactly matched as the circular1 one particle partially overlapping another1 so that they form less regular columns than the circular4 ,illustration3 ,fig4 ,,cxiii4 ,columnar arrangement which the particles of the human blood assume immediately after it is drawn from its vessel4 #bcf4 ,the red particles1 as far as is known1 constitute a distinct and peculiar form of animal matter3 the red colour1 according to some1 depending on an impregnation of iron2 according to others1 on an animal substance of a gelatinous nature4 #bcg4 ,the exact proportion of the different substances contained in the blood1 according to the most recent analysis of it1 that by ,m4 le ,canu1 is as follows1 namely1 ,water #ghfejj ,albumen #fidae ,fibrin #cefe ,colouring matter #aaifbf ,crystallizable fatty matter #dcjj ,oily matter #bbgj ,extractive matter1 soluble in alcohol and water #aibj ,albumen combined with soda #bjaj ,chloruret of sodium and potassium1 alkaline phosphate1 sulphate1 and subcarbonates #gcjd ,subcarbonate of lime and magnesia1 phosphates of lime1 magnesia and iron1 peroxide of iron #adad ,loss #behf -------- #ajjj #bch4 ,from the results of this analysis it is manifest that all the proximate principles of which the different tissues are composed exist in the blood1 namely1 albumen1 the proximate principle forming the basis of membrane2 fibrin1 the proximate principle forming the basis of muscle2 fatty matter1 forming the basis of nerve and brain2 and various saline and mineral substances1 forming a large part of bone1 and entering more or less into the composition of every fluid and solid4 #bci4 ,the blood1 which contains all the proximate constituents of the body1 and which1 by distributing them to the various tissues and organs1 maintains their integrity and life1 is itself alive4 ,the vitality of the blood is proved1-- #bdj4 i4 ,by its undergoing the process of death1 which it does just as much as the heart or the brain1 every time it is removed from the body4 ,while flowing in its living vessel1 the blood is permanently fluid4 ,its fluidity depends on a force of mutual repulsion exerted by its particles on each other4 ,that repulsive force is a vital endowment1 probably derived from the organic nerves so abundantly distributed to the inner coat of the blood-vessels4 ,when this vital influence is withdrawn1 which happens on the removal of the blood from its vessel1 the mass is no longer capable of remaining fluid2 the fibrin is converted into a solid2 the red particles1 instead of repelling1 attract each other1 forming the crude aggregate at the bottom of the clot2 coagulation is thus a process of death2 its commencement indicates a diminution of the vital energy of the blood2 during its progress that energy is constantly growing less and less2 the blood is dying2 and when complete1 the blood is dead4 #bda4 ,hence in every state of the system in which the vital energy of the blood is preternaturally increased1 coagulation is proportionably slow2 in every state in which its energy is diminished1 coagulation is rapid4 ,by copious and repeated blood-letting1 the vital energy is rapidly exhausted4 ,the effect of blood-letting on coagulation is determined by experiments instituted for the express purpose of ascertaining it4 ,blood was received from a horse at four periods1 about a minute and a half intervening between the filling of each cup4 ,minutes4 ,seconds4 ,in cup ,no4 #a4 coagulation began in #aa #aj #b4 #aj #e #c4 #i #ee #d4 #c #aj #bdb4 ,in like manner three cups were filled with the blood of a sheep1 at the interval of half a minute4 ,minutes4 ,seconds4 ,in cup ,no4 #a4 coagulation began in #b #aj #b4 #a #de #c4 #j #ee ,the same result was obtained in blood taken from a human subject4 ,a pound and a half of blood was removed from the arm of a woman labouring under fever1 a portion of which1 received into a tea-cup on the first effusion1 remained fluid for the space of seven minutes2 a similar quantity1 taken immediately before tying up the arm1 was coagulated in three minutes thirty seconds4 ,these experiments demonstrate that coagulation is rapid or slow as the vital energy of the blood is exhausted or unexhausted1 or that in proportion to the degree of life possessed by the blood is the space of time it takes in dying4 #bdc4 ,this result is referable to the principle already shown to be characteristic of living substance1--namely1 the power of resisting1 within a certain range1 the ordinary influence of physical agents4 ,the operation of this power is illustrated in a beautiful manner in a series of experiments performed by ,mr4 ,hunter on the egg and on blood4 ,this physiologist exposed a live1 that is1 a fresh egg to the temperature of the #agth and the #aeth degrees of ,fahrenheit2 it took half an hour to freeze it4 ,the egg was then thawed and exposed to #aj less cold1 namely1 to the #beth degree of ,fahrenheit2 it was now frozen in a quarter of an hour4 ,a living egg and one that had been killed by having been first frozen and then thawed1 were put together into a freezing mixture at #ae3 the dead was frozen twenty-five minutes sooner than the living egg4 ,the undiminished vitality of the fresh egg enabled it to resist the low temperature for the space of twenty-five minutes2 the vitality of the frozen egg having been destroyed1 it yielded at once to the influence of the physical agent4 ,on subjecting blood to analogous experiments1 the result was found to be the same4 ,blood immediately taken from the living vessel1 and blood previously frozen and then thawed1 being exposed to a freezing mixture1 a much shorter period and a much less degree of cold were required to freeze the latter than the former4 #bdd4 ii4 ,the vitality of the blood is proved by the change it undergoes in becoming a constituent part of an organized tissue4 ,the blood conveys to the several tissues the constituents of which they are composed2 each tissue selects from the mass of blood its own constituents and converts them into its own substance1 in which conversion1 since the blood always goes to the tissue in a fluid form1 the blood must necessarily pass from a fluid into a solid4 ,in the vessels the vital endowment of the blood maintains it permanently fluid2 in the structures the same power makes it and keeps it solid4 ,one and the same substance in one and the same body1 in one part is always fluid1 in another always solid2 the fluid is every moment passing into the solid and the solid into the fluid1 without intermixture and without interference4 ,nothing analogous to this is ever witnessed in inorganic matter1 in physical mechanism2 it is peculiar to the organized body and distinctive of the mechanism of life4 ,sometimes in physical mechanism we can perceive the mechanical arrangements and distinctly trace them from beginning to end3 in vital mechanism1 even when we can discern the mechanical arrangements1 we can seldom trace them beyond a step or two1 and never from beginning to end2 but arrangement and adaptation we know there must be in that which goes beyond1 no less than in that which keeps within1 our perception1 and we ought scarcely to question the existence of adjustments1 because they elude our sense1 when probably the very reason why they do so is that their delicacy and perfection immeasurably exceed any with which sense has made us acquainted4 #bde4 iii4 ,the vitality of the blood is proved by the process of organization4 ,we can trace only a few steps of this process1 but these are sufficient to establish the point in question4 ,blood effused from living vessels into the substance1 or upon the surface of living organs1 solidifies without losing vitality4 ,if a clot of blood be examined some time after it has thus become solid1 it is found to abound with blood-vessels4 ,some of these vessels are obviously derived from the surrounding living parts4 ,the minute vessels of these parts1 as can be distinctly traced1 elongate and shoot into the clot4 ,the clot thus acquires blood-vessels of its own4 ,by degrees a complete circulation is established within it4 ,the blood-vessels of the clot act upon the blood they receive just as the vessels of any other part act upon their blood1 that is transform it into the animal matter it is their office to elaborate4 ,in this manner a clot of blood is converted into a component part of the body1 and acquires the power of exercising its own peculiar and appropriate functions in the economy4 #bdf4 ,but while1 in this process1 some of the vessels of the clot can be distinctly traced from the surrounding living parts1 others appear to have no communication with those parts1 at all events no such communication can be traced4 ,these vessels1 the origin of which cannot be found external to the clot1 are supposed by some physiologists to be formed within it4 ,within the living egg1 during incubation1 certain motions or actions are observed spontaneously to arise1 which terminate in the development of the chick4 ,analogous motions arising within the clot terminate1 it is conceived1 in the development of blood-vessels4 ,according to this view1 a simultaneous action takes place in the clot1 and in the living part with which it is in contact2 each shooting out vessels which elongate1 approximate1 unite1 and thus establish a direct vital communication4 ,whether this view of the process of organization be the correct one or not does not affect the present argument4 ,it is certain that a clot of blood surrounded by living parts becomes organized2 it is certain that no dead substance surrounded by living parts becomes organized2 it follows that the blood possesses life4 #bdg4 ,health and life depend on the quantity1 quality1 and distribution of the blood4 ,the chief source from which the blood itself is derived is the chyle3 hence too much or too little food1 or too great or too little activity of the organs that digest it1 may render the quantity of the blood preternaturally abundant or deficient2 or though there be neither excess nor deficiency in the quantity of nourishment formed1 parts of the blood which ought to be removed may be retained1 or parts which ought to be retained may be removed1 and hence the actual quantity in the system may be superabundant or insufficient4 #bdh4 ,the relative proportion of every constituent of the blood is capable of varying2 and of course in the degree in which the healthy proportion is deranged1 the quality of the mass must undergo a corresponding deterioration4 ,the watery portion is sometimes so deficient1 that the mass is obviously thickened2 while at other times the fluid preponderates so much over the solid constituents1 that the blood is thin and watery4 ,the albumen1 the quantity of which varies considerably even in health1 in disease is sometimes twice as great1 and at other times is less than half its natural proportion4 ,in some cases the fibrin preponderates so much1 that the coagulum formed by the blood is exceedingly coherent1 firm and dense2 in other cases the quantity of fibrin is so small1 that the coagulation is imperfect1 forming only a soft1 loose and tender coagulum1 and in extreme cases the blood remains wholly fluid4 ,when the vital energy of the system is great1 the red particles abound2 when it is depressed1 they are deficient4 ,in the former state1 they are of a bright red colour2 in the latter1 dusky1 purple1 or even black4 ,when the depression of the vital energy is extreme1 the power of mutual repulsion exerted by the particles would seem to be so far destroyed as to admit of their adhering to each other partially in certain organs2 while in other cases they seem to be actually disorganised1 and to have their structures so broken up1 that they escape from the current of the circulation as if dissolved in the serum1 through the minute vessels intended only for the exhalation of the watery part of the blood4 ,this fearful change is conceived to have an intimate connexion with a diminution of the proportion of the saline constituents4 ,out of the body1 as has been shown1 the red particles change their figure instantaneously1 and are rapidly dissolved when in contact with pure water2 while they undergo little change of form if the water hold saline matter in solution4 ,it would seem that one use of the saline constituents of the blood is to preserve entire the figure and constitution of the red particles4 ,it is certain that any change in the proportion of the saline constituents produces a most powerful effect on the condition of the red particles4 ,it is no less certain that changes do take place in the proportion of the saline constituents4 ,in the state of health1 the taste of the blood is distinctly salt1 depending chiefly on the quantity of muriate of soda contained in it4 ,in certain violent and malignant diseases1 such1 for example1 as the malignant forms of fever1 and more especially that form of it termed pestilential cholera1 this salt taste is scarcely1 if at all1 perceptible2 and it is ascertained that1 in such cases1 the proportion of saline matter is sensibly diminished4 #bdi4 ,the quality of the blood may be also essentially changed by the disturbance of the balance of certain organic functions3 digestion1 absorption1 circulation1 respiration1 are indispensable to the formation of the blood and to the nourishment of the tissues4 ,absorption1 nutrition1 secretion1 circulation1 render the blood impure1 either by directly communicating to it hurtful ingredients1 or by allowing noxious matters to accumulate in it1 or by destroying the relative proportion of its constituents4 ,organs are specially provided1 the main function of which is to separate and remove from the blood these injurious substances4 ,organs of this class are called depurating1 and the process they carry on is denominated that of depuration4 ,the lungs1 the liver1 the kidneys1 are depurating organs1 and one result at least of the functions they perform is the purification or depuration of the blood4 ,if the lung fail to eliminate carbon1 the liver bile1 the kidney urine1 carbon1 bile1 urine1 or at least the constituents of which these substances are composed1 must accumulate in the blood1 contaminate it1 and render it incapable of duly nourishing and stimulating the organs4 #bej4 ,but though the blood be good in quality and just in quantity1 health and life must still depend upon its proper distribution4 ,it may be sent out to the system too rapidly or too slowly4 ,it may be distributed to different portions of the system unequally2 too much may be sent to one organ1 and too little to another3 consequently1 while the latter languishes1 the former may be oppressed1 overwhelmed or stimulated to violent and destructive action4 ,in either case health is disturbed and life endangered4 #bea4 ,of the mode and degree in which food1 air1 moisture1 temperature1 repletion1 abstinence1 exercise1 indolence1 influence the quantity1 quality1 and distribution of the blood2 of the mode in which the condition of the blood modifies the actions both of the organic and the animal organs2 of the reason why health and disease are wholly dependent on those states and actions1 a clear and just conception may be formed when the several functions have been described1 and the precise office of each is understood4 ,,chapter ,,vii4 ,,of ,,the ,,circulation4 ,vessels connected with the heart3 chambers of the heart--,position of the heart--,pulmonic circle3 systemic circle--,structure of the heart1 artery1 and vein--,consequences of the discovery of the circulation to the discoverer--,action of the heart3 sounds occasioned by its different movements--,contraction3 dilatation--,disposition and action of the valves--,powers that move the blood--,force of the heart--,action of the arterial tubes3 the pulse3 action of the capillaries3 action of the veins--,self-moving power of the blood--,vital endowment of the capillaries3 functions--,practical applications4 #beb4 ,the blood1 being necessary to nourish the tissues and to stimulate the organs1 must be in motion in order to be borne to them4 ,an apparatus is provided partly for the purpose of originating an impelling force to put the blood in motion1 and partly for the purpose of conveying the blood when in motion to the different parts of the body4 #bec4 ,the heart is the impelling organ2 the great vessels in immediate connexion with it are the transmitting organs 7fig4 ,,cxiv4 #a1 #b74 ,the heart is divided into two sets of chambers 7fig4 ,,cxiv4 #c1 #d1 #aj1 #aa71 one for the reception of the blood from the different parts of the body 7fig4 ,,cxiv4 #c1 #aj72 the other for the communication of the impulse which keeps the blood in motion 7fig4 ,,cxiv4 #d1 #aa74 ,the chamber which receives the blood is termed an auricle 7fig4 ,,cxiv4 #c1 #aj71 and is connected with a vessel termed a vein 7fig4 ,,cxiv4 #a1 #b1 #i72 that which communicates impulse to the blood is termed a ventricle 7fig4 ,,cxiv4 #d1 #aa71 and is connected with a vessel termed an artery 7fig4 ,,cxiv4 #g1 #ab74 ,the vein carries blood to the auricle2 the auricle transmits it to the ventricle2 the ventricle propels it into the artery2 the artery1 carrying it out from the ventricle1 ultimately sends it again into the vein1 the vein returns it to the auricle1 the auricle to the ventricle1 the ventricle to the artery1 and thus the blood is constantly moving in a circle2 hence the name of the process1 the circulation of the blood4 ,illustration3 ,fig4 ,,cxiv4 ,view of the heart with its several chambers exposed1 and the great vessels in connection with them4 #a4 ,the superior vena cava2 #b4 the inferior vena cava2 #c4 the chamber called the right auricle2 #d4 the chamber called the right ventricle2 #e4 the line marking the passage between the two chambers1 and the points of attachment of one margin of the valve2 #f4 the septum between the two ventricles2 #g4 the pulmonary artery arising from the right ventricle1 and dividing at #h1 into right and left for the corresponding lungs2 #i4 the four pulmonary veins bringing the blood from the lungs into #aj1 the left auricle2 #aa4 the left ventricle2 #ab4 the aorta arising from the left ventricle1 and passing down behind the heart to distribute blood1 by its divisions and subdivisions1 to every part of the body4 #bed4 ,in nourishing the tissues and stimulating the organs1 the blood parts with its nutritive and stimulating constituents1 and receives in return some ingredients which can no longer be usefully employed in the economy1 and others which are positively injurious4 ,an apparatus is established for its renovation and depuration2 this organ is termed the lung 7fig4 ,,lix4 #e71 and to this organ the blood must in like manner be conveyed4 ,thus the blood moves in a double circle1 one from the heart to the body and from the body back to the heart1 termed the systemic circle2 the other from the heart to the lung and from the lung back to the heart1 termed the pulmonic circle4 ,hence in the human body the heart is double1 consisting of two corresponding parts precisely the same in name1 in nature1 and in office2 the one appropriated to the greater1 or the systemic1 and the other to the lesser1 or the pulmonic circulation 7fig4 ,,cxiv474 #bee4 ,there is a complete separation between these two portions of the heart 7fig4 ,,cxiv4 #f71 formed by a strong muscular partition which prevents any communication between them except through the medium of vessels4 #bef4 ,the heart is situated between the two lungs 7fig4 ,,lix4 #b1 #e71 in the lower and fore part of the chest1 nearly in the centre1 but inclining a little to the left side4 ,its position is oblique 7fig4 ,,lix4 #b1 #e74 ,its basis is directed upwards1 backwards1 and towards the right 7fig4 ,,lix4 #b72 its apex is directed downwards1 forwards1 and towards the left1 opposite to the interval between the cartilages of the fifth and sixth ribs 7fig4 ,,lix4 #b74 ,it is inclosed in a bag termed the pericardium 7fig4 ,,cxv471 which consists of serous membrane4 ,the pericardium is considerably larger than the heart1 allowing abundant space for the action of the organ 7fig4 ,,cxv474 ,one part of the pericardium forms a bag around the heart 7fig4 ,,cxv472 the other part is reflected upon the heart so as to form its external covering 7fig4 ,,cxv471 and is continued for a considerable distance upon the great vessels that go to and from the heart in such a manner that this bag1 like all the serous membranes1 constitutes a shut sac4 ,both that portion of the pericardium which is reflected upon the heart1 and that which forms the internal surface of the bag around it1 is moistened during life by a serous fluid1 which1 after death1 is condensed into a small quantity of transparent water4 ,that portion of the pericardium which rests on the diaphragm 7fig4 ,,lxx4 #a7 is so firmly attached to it that it cannot be separated without laceration1 and by this attachment1 together with the great vessels at its base1 the heart is firmly held in its situation1 although in the varied movements of the body it is capable of deviating to a slight extent from the exact position here described4 ,illustration3 ,fig4 ,,cxv4 ,view of the heart enveloped in its pericardium1 the fore part of the latter being cut open and reflected back4 #beg4 ,when the interior of the heart is laid open there are brought into view four chambers 7fig4 ,,cxiv4 #c1 #d1 #aj1 #aa71 two for each circle4 ,those belonging to the pulmonic circle are on the right 7fig4 ,,cxiv4 #c1 #d71 those to the systemic on the left side of the body 7fig4 ,,cxiv4 #aj1 #aa72 hence the terms right and left are applied to these respective parts of the heart4 #beh4 ,the veins which carry the blood to the right or the pulmonic chambers are two1 one of which brings it from the upper1 and the other from the lower parts of the body3 the first is called the superior and the second the inferior vena cava 7fig4 ,,cxiv4 #a1 #b74 ,both pour their blood into the first chamber1 termed the right auricle 7fig4 ,,cxiv4 #c72 from the right auricle the blood passes into the second chamber1 denominated the right ventricle 7fig4 ,,cxiv4 #d73 from which springs the artery which carries the blood from the heart to the lung1 the pulmonary artery 7fig4 ,,cxiv4 #g74 ,this is the pulmonic circle4 ,from the lung the blood is returned to the heart by four veins1 termed the pulmonary veins 7fig4 ,,cxiv4 #i71 which pour the blood into the third chamber of the heart1 the left auricle 7fig4 ,,cxiv4 #aj74 ,from the left auricle it passes into the fourth chamber1 the left ventricle 7fig4 ,,cxiv4 #aa71 from which springs the artery which carries out the blood to the system1 termed the aorta 7figs4 ,,cxiv4 #ab1 and ,,cxvii4 #aa74 ,this is the systemic circle4 ,in the system the minute branches of the aorta unite with the minute branches that form the ven cav1 which return the blood to the right auricle of the heart1 and thus the double circle is completed4 #bei4 ,the two chambers called the auricles occupy the basis of the heart 7fig4 ,,cxiv4 #c1 #aj74 ,the right auricle is situated at the basis of the right ventricle 7figs4 ,,cxiv4 #c1 and ,,cxvi4 #d74 ,it is partly membranous and partly muscular4 ,at its upper and back part is the opening of the vena cava superior 7fig4 ,,cxvi4 #a71 which returns the blood to the heart from the head1 neck1 and all the upper parts of the body4 ,at its lower part is the opening of the vena cava inferior 7fig4 ,,cxvi4 #b71 which returns the blood from all the lower parts of the body4 ,illustration3 ,fig4 ,,cxvi4 ,view of the heart with the great vessels in connection with it1 on the right side1 its different chambers being laid open and its structure shown4 #a4 ,the vena cava superior2 #b4 the vena cava inferior2 #c4 cut edge of the right auricle turned aside to show1 #d4 the cavity of the right auricle into which the two ven cav pour the blood returned from all parts of the body2 #e4 hook suspending the reflected portion of the wall of the auricle2 #f4 the right ventricle2 #g4 cut edge of the wall of the ventricle1 a portion of which has been removed to show #h4 the cavity of the ventricle2 #i4 situation of the opening between the auricle and ventricle1 called the auricular orifice of the ventricle2 #aj4 valve placed between the auricle and ventricle1 one margin being firmly attached to the auriculo-ventricular opening in its entire extent1 the other lying loose in the cavity of the ventricle2 #aa4 probe passed from the auricle into the ventricle underneath the valve1 showing the course of the blood from the former chamber to the latter2 #ab4 the column carne attached by one extremity to the walls of the ventricle1 the other extremity ending in tendinous threads attached to the loose margin of the valve2 #ac4 passage to the pulmonary artery2 #ad4 the three semilunar valves placed at the commencement of #ae4 the pulmonary artery2 #af4 the two great branches into which the trunk of the pulmonary artery divides1 one branch going to each lung4 #bfj4 ,the auricle communicates with its corresponding ventricle by a large opening1 termed the auricular orifice of the ventricle 7figs4 ,,cxiv4 #e1 and ,,cxvi4 #i74 ,all around the opening is placed a thin but strong membrane 7fig4 ,,cxvi4 #aj71 one margin of which is firmly attached to the wall of the ventricle 7figs4 ,,cxiv4 #e1 and ,,cxvi4 #i71 while the other is free 7fig4 ,,cxvi4 #aj74 ,this membrane receives the name1 and1 as will be seen immediately1 performs the office of a valve4 #bfa4 ,the ventricle is much thicker and proportionally stronger than the auricle 7fig4 ,,cxvi4 #c1 #f74 ,it is composed almost entirely of muscular fibre4 ,over nearly the whole extent of its internal surface are placed irregular masses of muscular fibres1 many of which stand out from the wall of the ventricle like columns or pillars 7fig4 ,,cxvi4 #ab72 hence they are called fleshy columns 7column carne74 ,some of these fleshy columns are adherent by one extremity to the wall of the ventricle1 while the other extremity terminates in tendinous threads which are attached to the membrane that forms the valve 7fig4 ,,cxvi4 #ab74 #bfb4 ,from the upper and right side of this chamber springs the pulmonary artery 7fig4 ,,cxvi4 #ae72 at the entrance of which are placed three membranes of a crescent or semilunar shape1 termed the semilunar valves 7fig4 ,,cxvi4 #ad74 #bfc4 ,the structure of the left side of the heart is perfectly analogous to that of the right4 ,its auricle1 like that on the left side1 is placed at the base of the ventricle 7figs4 ,,cxiv4 #aj1 and ,,cxvii4 #b71 and like it also is thin1 being composed chiefly of membrane4 ,at its upper and back part 7figs4 ,,cxiv4 #i1 and ,,cxvii4 #a7 are the openings of the four pulmonary veins1 two from the right1 and two from the left lung4 #bfd4 ,at the passage of communication between the left auricle and ventricle is placed a valve analogous to that on the right side 7fig4 ,,cxvii4 #g74 ,illustration3 ,fig4 ,,cxvii4 ,view of the heart with the great vessels in connection with it1 on the left side1 its chambers being laid open as in the preceding figure4 #a4 ,the four pulmonary veins opening into1 #b4 the cavity of the left auricle2 #c4 the cut edge of the wall of the auricle2 #d4 the appendix of the auricle2 #e4 the cavity of the left ventricle2 #f4 the cut edge of the wall of the ventricle1 the greater portion of the wall having been removed to show the interior of the chamber2 #g4 valve placed between the auricle and ventricle2 #h4 column carne terminating in tendinous threads attached to the loose margin of the valve2 #i4 probe passed underneath the valve and its tendinous threads1 raising them from the wall of the ventricle similar to a refluent current of blood2 #aj4 passage to #aa4 the aorta2 #ab4 two of the semilunar valves placed at the mouth of the aorta1 the third having been cut away2 #ac4 arch of the aorta2 #ad4 the three semilunar valves at the commencement of the pulmonary artery seen in action1 completely closing the mouth of the vessel4 #bfe4 ,the walls of the left ventricle are nearly as thick again as those of the right1 and its fleshy columns are much larger and stronger4 ,from the upper and back part of this fourth chamber 7fig4 ,,cxvii4 #aa7 springs the great systemic artery1 the aorta1 around the mouth of which are placed three semilunar valves 7fig4 ,,cxvii4 #ab71 similar to those at the mouth of the pulmonary artery4 #bff4 ,the partition which divides the two sets of chambers from each other 7fig4 ,,cxiv4 #f7 is wholly composed of muscular fibres1 and is called the septum of the heart4 #bfg4 ,the external surface of the heart is covered by a thin but strong membrane continued over it from the pericardium4 ,between this membranous covering and its fleshy substance is lodged1 even when the body is reduced to the greatest degree of thinness1 a quantity of fat4 ,immediately beneath this fat are the fleshy fibres that compose the main bulk of the organ4 ,these fibres are arranged in a peculiar manner4 ,the arrangement is not perceptible when the heart is examined in its natural state1 but after it has been subjected to long-continued boiling1 which1 besides separating extraneous matters from the fibres1 hardens and loosens without displacing them1 the manner in which they are disposed is manifest4 ,just at the point where the muscular fibres that constitute the septum of the auricles are set upon those which form the septum of the ventricles1 and parallel with the origin of the aorta1 the heart is not muscular but tendinous4 ,the substance called tendon1 it has been shown1 is often employed in the body to afford origin or insertion to muscular fibres1 performing1 in fact1 the ordinary office of bone1 and substituted for it in situations where bone would be inconvenient4 ,from the tendinous matter just indicated most of the fibres that constitute the muscular walls of the heart take their origin4 ,from this point the fibres proceed in different directions3 those which go to form the wall of the auricles ascend2 those which form the wall of the ventricles pursue an oblique course downwards1 and the arrangement of the whole is such1 that a general contraction of the fibres must necessarily bring all the parts of the heart towards this central tendinous point4 ,the object and the result of this arrangement will be manifest immediately4 #bfh4 ,the internal surface of the chambers of the heart1 in its whole extent1 is lined by a fine transparent serous membrane1 which renders it smooth and moist2 and1 like all other organs which have important functions to perform1 it is plentifully supplied with blood-vessels and nerves4 #bfi4 ,such is the structure of the organ that moves the blood4 ,the artery1 the tube that carries it out from the heart1 is a vessel composed of three distinct layers of membrane superimposed one upon another1 and intimately united by delicate cellular tissue4 ,these layers are termed tunics or coats4 ,the external coat 7fig4 ,,cxviii4 #c71 which is also called the cellular1 consists of minute whitish fibres1 which are dense and tough1 and closely interlaced together in every direction4 ,they form a membrane of great strength1 the elasticity of which1 especially in the longitudinal direction1 is such that1 in addition to its other names1 it has received that of the elastic coat4 ,illustration3 ,fig4 ,,cxviii4 ,portion of an artery1 showing the several coats of which it is composed separated from each other4 #a4 ,the internal or serous coat2 #b4 the middle or fibrous coat2 #c4 the external or cellular coat4 #bgj4 ,the middle or the fibrous tunic is composed of yellowish flattened fibres which pass in an oblique direction around the calibre of the vessel1 forming segments of circles1 which1 uniting1 produce complete rings 7fig4 ,,cxviii4 #b74 ,this tunic is thick1 consisting of several layers of fibres which it is easy to peel off in succession4 ,they form a firm1 solid1 elastic1 but1 at the same time1 brittle membrane4 #bga4 ,the inner tunic1 thin1 colourless1 nearly transparent1 and perfectly smooth1 is moistened by a serous fluid1 and is thence called the serous coat 7fig4 ,,cxviii4 #a74 ,to the naked eye it presents no appearance of fibres1 yet notwithstanding its extreme delicacy1 it is so strong that1 after the other coats of the artery have been entirely removed in a living animal1 it is capable of resisting the impetus of the circulation1 and of preventing the dilatation of the artery4 ,the arteries themselves are supplied with arteries1 vessels that nourish their tissues1 and which are sent to them from neighbouring branches1 seldom or never from the vessel itself to which they are distributed4 ,each individual part of an artery is supplied by its own appropriate vessels1 which form but few communications above and below1 so that if care be not taken in surgical operations to disturb these nutrient arteries very little1 the vessel will perish for want of sustenance4 #bgb4 ,the vein1 the tube that carries back the blood to the heart1 is composed of the same number of tunics as the artery1 which1 with the exception of the middle1 are essentially the same in structure1 but they are all much thinner4 ,the external tunic consists of a less dense and strong cellular membrane2 the middle tunic1 instead of being formed of elastic rings1 is composed of soft and yielding fibres1 disposed in a longitudinal direction2 while the inner coat1 which is still more delicate than that of the artery1 is arranged in a peculiar manner4 ,the inner coat of most veins1 at slight intervals1 is formed into folds 7fig4 ,,cxx4 #e71 one margin of which is firmly adherent to the circumference of the vessel1 while the other margin is free and turned in the direction of the heart4 ,these membranous folds are termed valves4 ,in all veins the diameter of which is less than a line the valves are single2 in most veins of greater magnitude they are placed in pairs1 while in some of the larger trunks they are triple1 and in a few instances quadruple1 and even quintuple4 ,the veins1 like the arteries1 are supplied with nutrient vessels and nerves4 #bgc4 ,all the arteries of the body proceed from the two trunks already described2 that connected with the pulmonic circle1 the pulmonary artery1 and that connected with the systemic circle1 the aorta4 ,these vessels1 as they go out from the heart and proceed to their ultimate termination1 are arborescent1 that is1 they successively increase in number and diminish in size1 like the branches of a tree going off from the trunk 7fig4 ,,cxix4 #a1 #b1 #c74 ,each trunk usually ends by dividing into two or more branches 7fig4 ,,cxix4 #a1 #b71 the combined area of which is always greater than that of the trunk from which they spring1 in the proportion of about one and a half to one4 ,as the branch proceeds to its ultimate termination it divides and subdivides1 until at length the vessel becomes so minute1 that it can no longer be distinguished by the eye4 ,these ultimate branches are called capillary vessels1 from their hair-like smallness 7fig4 ,,cxix4 #d72 but this term does not adequately express their minuteness4 ,it has been stated 7#bcd7 that the red particle of the blood1 at the medium calculation1 is not more than the three-thousandth part of an inch in diameter2 yet vast numbers of the capillary vessels are so small that they are incapable of admitting one of these particles1 and receive only the colourless portion of the blood4 ,illustration3 ,fig4 ,,cxix4 ,view of the manner in which an artery divides and subdivides into its ultimate branches4 #a4 ,trunk of the artery2 #b4 large branches into which it subdivides2 #c4 small branches1 successively becoming smaller and smaller until they terminate in #d4 the capillary branches4 #bgd4 ,every portion of an artery1 by reason of the elasticity of its coats1 preserves nearly a cylindrical form1 and as the area of the branches is greater than that of the trunks1 the blood1 in proceeding from the heart to the capillaries1 though passing through a series of descending cylinders1 is really flowing through an enlarging space4 #bge4 ,the disposition of the veins1 like that of the arteries1 is arborescent1 but in an inverse order2 for the course of the veins is from capillary vessels to visible branches1 and from visible branches to large trunks 7fig4 ,,cxx4 #a1 #b1 #c74 ,in every part of the body where the capillary arteries terminate the capillary veins begin1 and the branches uniting to form trunks1 and the small to form large trunks1 and the trunks always advancing towards the heart1 and always increasing in magnitude as they approach it1 form at length the two veins which it has been stated 7#beh7 return all the blood of the body to the right auricle of the heart4 ,illustration3 ,fig4 ,,cxx4 ,view of the manner in which the minute branches of the vein unite to form the larger branches and the trunks4 #a4 ,capillary venous branches2 #b4 small branches formed by the union of the capillary2 #c4 larger branches formed by the union of the smaller and gradually increasing in size1 to form the great trunk1 #d4 a portion of which is laid open to show its inner surface and the arrangement of #e4 the valves formed by its inner coat4 #bgf4 ,the veins are very much more numerous than the arteries1 for they often consist of double sets1 and they are at the same time more capacious and more extensible4 ,reckoning the whole of the blood at one-fifth of the weight of the body1 it is estimated that1 of this quantity1 about one-fourth is in the arterial and the remaining three-fourths in the venous system4 ,the combined area of the branches of the veins is much greater than that of the two trunks in which they terminate 7fig4 ,,cxx4 #a1 #b1 #c1 #d73 the blood1 therefore1 in returning to the heart1 is always flowing from a large into a smaller space4 #bgg4 ,the divisions and subdivisions of the artery freely communicate in all parts of the body by means of what are called anastomosing branches1 and this communication of branch with branch and trunk with trunk is termed anastomosis4 ,the same intercommunication1 but with still greater freedom and frequency1 takes place among the branches of veins4 ,in both orders of vessels the communication is frequent in proportion to the minuteness of the branch and its distance from the heart4 ,it is also more frequent in proportion as a part is exposed to pressure2 hence the minute arteries and veins about a joint are distinguished for the multitude of their anastomosing branches2 and above all1 it is frequent in proportion to the importance of the organ2 hence the most remarkable anastomosis in the body is in the brain4 ,by this provision care is taken that no part be deprived of its supply of blood2 for if one channel be blocked up1 a hundred more are open to the current1 and the transmission of it to any particular region or organ by two or more channels1 instead of through one trunk1 is a part of the same provision4 ,thus the fore-arm possesses four principal arteries with corresponding veins1 and the brain receives its blood through four totally independent canals#f4 #bgh4 ,that the blood is really a flowing stream1 and that it pursues the course described 7#beh71 is indubitable4 ,for1 7#a47 ,with the microscope1 in the transparent parts of animals1 the blood can be seen in motion 7fig4 ,,cxxi472 and if its course be attentively observed1 its route may be clearly traced4 ,illustration3 ,fig4 ,,cxxi4 ,view of the circulation of the blood as seen under the microscope in the web of the frog's foot4 7#b47 ,the membranes termed valves are so placed as to allow of the freest passage to the blood in the circle described1 while they either altogether prevent or exceedingly impede its movement in any other direction4 7#c47 ,the effect of a ligature placed around a vein and an artery1 and of a puncture made above the ligature in the one vessel and below it in the other1 demonstrate both the motion of the blood and the course of it4 ,when a ligature is placed around a vein1 that part of the vessel which is most distant from the heart becomes full and turgid on account of the accumulation of blood in it2 while the part of the vessel which is between the ligature and the heart becomes empty and flaccid1 because it has carried on its contents to the heart1 and it can receive no fresh supply from the body4 ,when1 on the contrary1 a ligature is placed around an artery1 that portion of the vessel which lies between the ligature and the heart becomes full and turgid1 and the other portion empty and flaccid4 ,this can only be because the contents of the two vessels move in opposite directions1--from the heart to the artery1 from the artery to the vein1 and from the vein to the heart4 ,at the same time1 if the vein be punctured above the ligature1 there will be little or no loss of blood2 while if it be punctured below the ligature1 the blood will continue to flow until the loss of it occasions death1 which could not be unless the blood were in motion1 nor unless the direction of its course were from the artery to the vein and from the vein to the heart4 7#d47 ,if fluids be injected into the veins or arteries1 whether of the dead or of the living body1 they readily make their way and fill the vessels1 if thrown in the direction stated to be the natural course of the circulation2 but they are strongly resisted if forced in the opposite direction4 #bgi4 ,such is the description1 and with the exception of the first proof1 such the evidence of the circulation of the blood in the human body1 pretty much as it was given by the discoverer of it1 the illustrious ,harvey4 ,before the time of ,harvey1 a vague and indistinct conception that the blood was not without motion in the body had been formed by several anatomists4 ,it is analogous to the ordinary mode in which the human mind arrives at discovery 7chap4 iii41 p4 #ajc71 that many minds should have an imperfect perception of an unknown truth1 before some one mind sees it in its completeness and fully discloses it4 ,having1 about the year #afbj1 succeeded in completely tracing the circle in which the blood moves1 and having at that time collected all the evidence of the fact1 with a rare degree of philosophical forbearance1 ,harvey still spent no less than eight years in re-examining the subject1 and in maturing the proof of every point1 before he ventured to speak of it in public4 ,the brief tract which at length he published was written with extreme simplicity1 clearness1 and perspicuity1 and has been justly characterised as one of the most admirable examples of a series of arguments deduced from observation and experiment that ever appeared on any subject4 #bhj4 ,cotemporaries are seldom grateful to discoverers4 ,more than one instance is on record in which a man has injured his fortune and lost his happiness through the elucidation and establishment of a truth which has given him immortality4 ,it may be that there are physical truths yet to be brought to light1 to say nothing of new applications of old truths1 which1 if they could be announced and demonstrated to-day1 would be the ruin of the discoverer4 ,it is certain that there are moral truths to be discovered1 expounded1 and enforced1 which1 if any man had now penetration enough to see them1 and courage enough to express them1 would cause him to be regarded by the present generation with horror and detestation4 ,perhaps1 during those eight years of re-examination1 the discoverer of the circulation sometimes endeavoured in imagination to trace the effect which the stupendous fact at the knowledge of which he had arrived would have on the progress of his favourite science2 and1 it may be1 the hope and the expectation occasionally arose that the inestimable benefit he was about to confer on his fellow men would secure to him some portion of their esteem and confidence4 ,what must have been his disappointment when he found1 after the publication of his tract1 that the little practice he had had as a physician1 by degrees fell off4 ,he was too speculative1 too theoretical1 not practical4 ,such was the view taken even by his friends4 ,his enemies saw in his tract nothing but indications of a presumptuous mind that dared to call in question the revered authority of the ancients2 and some of them saw1 moreover1 indications of a malignant mind1 that conceived and defended doctrines which1 if not checked1 would undermine the very foundations of morality and religion4 ,when the evidence of the truth became irresistible1 then these persons suddenly turned round and said1 that it was all known before1 and that the sole merit of this vaunted discoverer consisted in having circulated the circulation4 ,the pun was not fatal to the future fame of this truly great man1 nor even to the gradual though slow return of the public confidence even during his own time2 for he lived to attain the summit of reputation4 #bha4 ,it is then indubitably established that the whole blood of the body in successive streams is collected and concentrated at the heart4 ,the object of the accumulation of a certain mass of it at this organ is to subject it to the action of a strong muscle1 and thereby to determine its transmission with adequate force and precision through the different sets of capillary vessels4 #bhb4 ,in the accomplishment of this object the heart performs a twofold action2 that of contraction and that of dilatation4 ,the auricles contract and thereby diminish their cavities1 then dilate and thereby expand them1 and the one action alternates with the other4 ,there is the like alternate contraction and dilatation of the ventricles4 ,the first action is termed systole1 the second diastole1 and both are performed with force4 #bhc4 ,when the heart is laid open to view in a living animal1 and its movements are carefully observed1 it is apparent that the two auricles contract together2 that the two ventricles contract together2 that these motions alternate with each other1 and that they proceed in regular succession4 ,the interval between these alternate movements is1 however1 exceedingly short1 and can scarcely be perceived when the heart is acting with full vigour2 but it is evident when its action is somewhat languid4 #bhd4 ,when the ventricles contract1 the apex of the heart is drawn upwards1 and at the same time raised or tilted forwards4 ,it is during this systole of the ventricles1 and in consequence of this result of their action1 that the apex of the heart gives that impulse against the walls of the chest which is felt in the natural state between the fifth and sixth ribs1 and which just perceptibly precedes the pulse at the wrist4 #bhe4 ,when the ear is applied to the human chest1 over the situation of the heart1 a dull and somewhat prolonged sound is heard1 which precedes and accompanies the impulse of the heart against the chest4 ,this dull sound is immediately succeeded by a shorter and sharper sound3 after this there is a short pause2 and then the dull sound and impulse are again renewed4 ,the duller sound and stronger impulse are ascribed to the contraction of the ventricles1 and the sharper sound and feebler impulse to that of the auricles4 #bhf4 ,the movement of the heart is effected by the contraction of its muscular fibres4 ,those fibres rest1 as upon a firm support1 on the tendinous matter to which they are attached1 from which they diverge1 and towards which their contraction must necessarily bring all the parts of the heart 7#bfg74 ,the result of their contraction is the powerful compression of all the chambers of the heart1 and thereby the forcible ejection of their contents through the natural openings4 #bhg4 ,but the chambers1 alternately with forcible contraction1 perform the action of forcible dilatation4 ,this movement of dilatation is effected by the reaction of the elasticity of the tendinous matter on which the muscular fibres are supported 7#bfg74 ,this highly elastic substance1 by the contraction of the fibres1 is brought into a state of extreme tension4 ,the contraction of the fibres ceasing1 that moment the tense tendon recoils with a force exactly proportionate to the degree of tension into which it had been brought4 ,thus the very agent that is employed forcibly to close the chamber is made the main instrument of securing its instantaneous re-opening4 ,a vital energy is appointed to accomplish what is indispensable1 and what nothing else can effect1 the origination of a motive power2 a physical agent is conjoined to perform the easier task to which it is competent2 and the two powers1 the vital and the physical1 work in harmony1 each acting alternately1 and each1 with undeviating regularity and unfailing energy1 fulfilling its appropriate office4 #bhh4 ,when the chambers of the heart which open into each other1 and which as freely communicate with the great vessels that enter and proceed from them1 are forcibly closed1 and the blood they contain is projected from them1 how is one uniform forward direction given to the current8 ,why1 when the right ventricle contracts1 is the blood not sent back into the right auricle1 as well as forward into the pulmonary artery8 ,there is but one mode of preventing such an event1 which is to place a flood-gate between the two chambers2 and there a flood-gate is placed1 and that flood-gate is the valve4 ,as long as the blood proceeds onwards in the direct course of the circulation1 it presses this membrane close to the side of the heart1 and thereby prevents it from occasioning any impediment to the current4 ,when1 on the contrary1 the blood is forced backwards1 and attempts to re-enter the auricle1 being of course driven in all directions1 some of it passes between the wall of the ventricle and the valve4 ,the moment it is in this situation it raises up the valve1 carries it over the mouth of the passage1 and shuts up the channel4 ,there cannot be a more perfect flood-gate4 #bhi4 ,this is beautiful mechanism2 but there is another arrangement which surpasses mere mechanism1 however beautiful4 ,it has been shown 7#bfj7 that one edge of the membrane that forms the valve is firmly adherent to the wall of the ventricle1 while the other edge1 when not in action1 appears to lie loosely in the ventricle 7fig4 ,,cxvi4 #aj74 ,were this edge really loose the refluent current would carry it back completely into the auricle1 and so counteract its action as a valve2 but it is attached to the tendinous threads proceeding from the fleshy columns that stand along the wall of the ventricle 7fig4 ,,cxvi4 #ab74 ,by these tendinous threads1 as by so many strings1 the membrane is firmly held in its proper position 7fig4 ,,cxvi4 #aj1 #ab72 and the refluent current cannot carry it into the auricle4 ,thus far the arrangement is mechanical4 ,but each of these fleshy columns is a muscle1 exerting a proper muscular action4 ,among the stimulants which excite the contractility of the muscular fibre1 one of the most powerful is distension4 ,the refluent current distends the membrane2 the distension of the membrane stretches the tendinous threads attached to it2 the stretching of its tendinous threads stretches the fleshy column2 by this distension of the column it is excited to contraction2 by the contraction of the column its thread is shortened2 by the shortening of the thread the valve is tightened1 and that in the exact degree in which the thread is shortened4 ,so1 the greater the impetus of the refluent blood1 the greater the distension of the membrane2 and the greater the distension of the membrane1 the greater the excitement of the fleshy column2 the greater the energy with which it is stimulated to act1 the greater1 therefore1 the security that the valve will be held just in the position that is required1 with exactly the force that is needed4 ,here1 then1 is a flood-gate not only well constructed as far as regards the mechanical arrangement1 but so endowed as to be able to act with additional force whenever additional force is requisite2 to put forth on every occasion1 as the occasion arises1 just the degree of strength required1 and no more4 #bij4 ,the contraction of the heart is the power that moves the blood2 and this contraction generates a force which is adequate to impel it through the circle4 ,from experiments performed by ,dr4 ,hales it appears that if the artery of a large animal1 such as the horse1 be made to communicate with an upright tube1 the blood will ascend in the tube to the height of about ten feet above the level of the heart1 and will afterwards continue there rising and falling a few inches with each pulsation of the heart4 ,in this animal1 then1 the heart acts with a force capable of maintaining a column of ten feet4 ,now a column of ten feet indicates a pressure of about four pounds and a half in a square inch of surface4 ,suppose the human heart to be capable of supporting a column of blood eight feet high1 this will indicate a pressure of four pounds to the square inch2 but the left ventricle of the heart1 while it injects its column of blood into the aorta1 has to overcome the inertia of the quantity of blood projected2 of the mass already in the artery1 and of the elasticity of the vessel yielding to a momentary increase of pressure3 it is probable1 therefore1 that the heart acts with a force of six pounds on the inch4 ,the left ventricle1 when distended1 has about ten square inches of internal surface2 consequently the whole force exerted by it may be about sixty pounds4 ,according to the calculation of ,hales1 it is fifty-one and a half4 ,now1 it is proved by numerous experiments1 that1 after death1 a slight impulse with the syringe1 certainly much less than that which is acting upon the blood in the same artery during life1 is sufficient to propel a solution of indigo1 or fresh drawn blood1 from a large artery into the extreme capillary4 ,if1 therefore1 after death1 a slight force will fill the capillaries1 a force during life equal to sixty pounds must be adequate to do so4 #bia4 ,the heart1 with a force equal to the pressure of sixty pounds1 propels into the artery two ounces of blood at every contraction4 ,it contracts four thousand times in an hour4 ,there passes through the heart1 therefore1 every hour1 eight thousand ounces or seven hundred pounds of blood4 ,it has been stated 7#baf7 that the whole mass of blood in an adult is about twenty-eight pounds3 on an average the entire circulation is completed in two minutes and a half2 consequently a quantity of blood equal to the whole mass passes through the heart from twenty to twenty-four times in an hour4 ,but though the average space of time requisite to accomplish a complete circulation may be two minutes and a half1 yet when a stream of blood leaves the heart1 different portions of it must finish their circle at very different periods1 depending in part upon the length of the course which they have to go1 and in part upon the degree of resistance that obstructs their passage4 ,a part of the stream1 it is obvious1 finishes its course in circulating through the heart itself2 another portion takes a longer circuit through the chest2 another extends the circle round the head2 and another visits the part placed at the remotest distance from the central moving power4 ,such is the velocity with which the current sometimes goes1 that1 in the horse1 a fluid injected into the great vein of the neck1 on one side1 has been detected in the vein on the opposite side1 and even in the vein of the foot1 within half a minute4 #bib4 ,it has been shown 7#bhb7 that the different chambers of the heart have a tendency to perform their movements in a uniform manner1 and in a successive order2 that they contract and dilate in regular alternation1 and at equal intervals2 but1 moreover1 they continue these movements equally without rest and without fatigue4 ,on go the motions1 night and day1 for eighty years together1 at the rate of a hundred thousand strokes every twenty-four hours1 alike without disorder1 cessation1 or weariness4 ,the muscles of the arm tire after an hour's exertion1 are exhausted after a day's labour1 and can by no effort be made to work beyond a certain period4 ,there is no appreciable difference between the muscular substance of the heart and that of the arm4 ,it is true that the heart is placed under one condition which is peculiar4 ,muscles contract on the application of stimuli2 and different muscles are obedient to different stimuli1--the voluntary muscles to the stimulus of volition1 and the heart to that of the blood4 ,the exertion of volition is not constant1 but occasional2 the muscle acts only when it is excited by the application of its stimulus3 hence the voluntary muscle has considerable intervals of rest4 ,the blood1 on the contrary1 is conveyed to the heart without ceasing1 in a determinate manner1 in a successive order2 and this is the reason why through life its action is uniform3 it uniformly receives a due supply of its appropriate stimulus4 ,but why it is unwearied1 why it never requires rest1 we do not know4 ,we know the necessities of the system which render it indispensable that it should be capable of untiring action1 for we know that the first hour of its repose would be the last of life2 but of the mode in which this wonderful endowment is communicated1 or of the relations upon which it is dependent1 we are wholly ignorant4 #bic4 ,the force exerted by the heart is vital4 ,it is distinguished from mechanical force in being produced by the very engine that exerts it4 ,in the best-constructed machinery there is no real generation of power4 ,there is merely concentration and direction of it4 ,in the recoil of the spring1 in the reaction of condensed steam1 the energy of the expansive impulse is never greater than the force employed to compress or condense1 and the moment this power is expended all capacity of motion is at an end4 ,but the heart produces a force equal to the pressure of sixty pounds by the gentlest application of a bland fluid4 ,here no force is communicated to be again given out1 as in every mechanical moving power2 but it is new power1 power really and properly generated2 and this power is the result of vital action1 and is never in any case the result of action that is not vital4 #bid4 ,the heart projects the blood with a given force into the arterial tubes4 ,the arteries in the living body are always filled to distension1 and somewhat beyond it1 by the quantity of blood that is in them4 ,it has been shown that the elasticity of their coats is such as to give to them1 even after death1 the form of open hollow cylinders 7#bgd74 ,during life they are kept in a state of distension by the quantity of blood they contain4 ,by virtue of their elasticity they react upon their contents with a force exactly proportioned to the degree of their distension1 that is1 with a force at least adequate to keep them always open and rigid4 #bie4 ,these open and rigid tubes1 already filled to distension1 and somewhat beyond it1 receive at every contraction of the heart a forcible injection of a new wave of blood4 ,the first effect of the injection of this new wave into a tube previously full to distension1 is to cause the current to proceed by jerks or jets1 each jerk or jet corresponding to the contraction of the heart4 ,and1 accordingly1 by this jet-like motion1 the flow of the blood in the artery is distinguished from that in the vein1 in which latter vessel the current is an equal and tranquil stream4 #bif4 ,the second effect of this new wave is to occasion some further distension of the already distended artery1 and accordingly1 when the vessel is exposed in a living animal1 and its action carefully observed1 a slight augmentation of its diameter is distinguishable at every contraction of the heart4 ,this new wave while it distends must at the same time slightly elongate the vessel2 cause its straight portions to bend a little1 and its curved portions to bend still more2 and1 consequently1 in some situations1 to lift it a little from its place1 giving it a slight degree of locomotion2--and these two causes combined produce the pulse4 ,when the finger is pressed gently on an artery1 at the instant of the contraction of the heart1 the vessel is felt to bound against the finger with a certain degree of force3 this1 as just stated1 is owing to a slight distension of the vessel by the new wave of blood1 together with a slight elongation of it1 and a gentle rising from its situation4 #big4 ,the blood1 in flowing through the arterial trunks and branches to the capillaries1 through the arterial to the venous capillaries1 and through the venous branches and trunks back to the heart1 is exposed to numerous and powerful causes of retardation3 such1 for example1 as the friction between the blood and the sides of the vessels1 the numerous curves and angles formed by the branches in springing from the trunks1 the tortuous course of the vessels in many parts of the body1 and the increasing area of the arterial branches as they multiply and subdivide4 ,yet the extraordinary fact has been recently discovered1 that the blood moves with the same momentum or force in every part of the arterial system1 in the aorta1 in the artery in the neck which carries the blood to the head 7the carotid artery71 in the artery of the arm 7the humeral artery71 in the artery of the lower extremity 7the femoral artery72 in a word1 in the minute and remote capillary1 and in the large trunk near the heart4 ,having contrived an instrument by which the force of the blood as it flows in its vessel could be accurately indicated by the rise of mercury in a tube1 ,m4 ,poiseuille found that the elevation of the mercury is uniformly the same in the different arteries of the same animal1 whatever the size of the artery and its distance from the heart4 ,this tube was inserted1 for example1 into the common carotid artery of a horse3 the diameter of the vessel was #cd_/ajjths of an inch2 its distance from the heart was thirty-nine inches2 the height to which the mercury rose in the graduated tube was accurately marked4 ,the tube was then inserted into a muscular branch of the artery in the thigh3 the diameter of this vessel was #g_/ajjths of an inch1 and its distance from the heart #fg inches4 ,according to the mean of nine observations1 the mercury rose in both tubes to precisely the same elevation4 ,here is another instance of the beautiful adjustments everywhere established in the living economy4 ,the blood is sent by a living engine1 moving under laws peculiar to the state of life1 into living vessels1 which in their turn acting under laws peculiar to the state of life1 so accommodate themselves to the current as absolutely to offer no resistance to its progress2 so accommodate themselves to the moving power1 as completely and everywhere to obviate the physical impediments to motion inseparable from inorganic matter4 #bih4 ,that the arterial tubes do possess and exert a truly vital power1 modifying the current of the blood they contain1 is indubitably established4 #a4 ,if in a living animal the trunk of an artery be laid bare1 the mere exposure of it to the atmospheric air causes it to contract to such a degree1 that its size becomes obviously and strikingly diminished4 ,this can result only from the exertion of a vital property1 for no dead tube is capable in such a manner of diminishing its diameter4 #b4 ,if during life an artery be opened and the animal be largely bled1 the arteries become progressively smaller and smaller as the quantity of blood in the body diminishes4 ,if the bleeding be continued until the animal dies1 and the arteries of the system be immediately examined1 they are found to be reduced to a very small size2 if again examined some time after death1 they are found to have become larger1 and they go on growing successively larger and larger until they regain nearly their original magnitude1 which they retain until they are decomposed by putrefaction4 #c4 ,m4 ,poiseuille distended with water the artery of an animal just killed4 ,this water was urged by the pressure of a given column of mercury4 ,the force of the reaction of the artery was now measured by the height of a column of mercury which the water expelled from the artery could support4 ,it was found that the artery reacted with a force greater than that employed to distend it1 and greater than the same artery could exert some time after death2 but since mechanical reaction can never be greater than the force previously exerted upon it 7#bic71 it follows that the excess of the reaction indicated in this case was vital4 #d4 ,if an artery be exposed and a mechanical or chemical stimulus be applied to it1 its diameter is altered1 sometimes becoming larger and sometimes smaller1 according to the kind of agent employed4 #bii4 ,any one of these facts1 taken by itself1 affords a demonstration that the arterial trunks and branches are capable of enlarging and diminishing their diameter by virtue of a vital endowment4 ,there is complete evidence that the exertion of this vital power on the part of the arterial trunk is not to communicate to the blood the smallest impulsive force2 the engine constructed for the express purpose of working the current generates all the force that is required2 but the labour of the engine is economized by imparting to the tubes that receive the stream a vital property1 by which they wholly remove the physical obstructions to its motion4 #cjj4 ,driven by the heart through the arterial branches into the capillaries1 the blood courses along these minute vessels urged by the same power4 ,the most careful observers1 from ,haller and ,spalanzani down to the present time1 concur in stating that the pulsatory movement communicated by the heart to the blood in the great arteries is distinctly visible under the microscope in the capillaries4 ,i have often observed in frogs and tadpoles1 and once in the bat1 says ,wedemeyer1 that when the circulation was becoming feeble1 the blood in the finest capillaries advanced by jerks1 corresponding with the contractions of the heart4 ,i remarked the same appearance in the fine veins several times in the toad and tadpole1 and once in the frog4 ,if an experimenter so dispose the circulation of the limb of an animal that the flow of blood be confined to the branches of a single artery1 and a corresponding vein1 it is found that the blood stagnates in the vein whenever the current in the artery is stopped by a ligature1 but no sooner is the ligature removed from the artery1 than the blood begins again to flow freely along the vein1 the capillaries of the artery which have to send on the current to those of the vein being now again within the influence of the heart4 ,and if the impulse of the heart be removed from the capillary system1 by placing a ligature around the aorta1 the capillary circulation is uniformly and completely stopped4 #cja4 ,it was found by ,dr4 ,hales1 that1 under ordinary circumstances1 the blood rises in a tube connected with a vein to the height only of six inches1 while it has been shown 7#bij7 that in the artery it ascends as high as ten feet4 ,this prodigious difference between the venous and the arterial tension led to the conclusion that the impulsive force of the heart was all but exhausted before the blood reached the veins1 and set physiologists on the search for other powers to carry on the venous circulation4 ,it was overlooked that the blood has an open and ready escape from the great trunks of the veins through the right chambers of the heart1 and that in consequence of this free escape of their fluid1 these vessels indicate no greater tension than is just sufficient to lift the blood to the heart1 and to overcome friction#g4 ,m4 ,magendie having laid bare the chief artery and vein of a living limb1 and having raised the vessels in such a manner that he could place a ligature around the former1 without including the latter1 found that the flow of blood from a puncture made below a ligature on the vein1 was rapid or slow1 according as the heart was allowed to produce a greater or less degree of tension in the artery1 which tension was regulated by compressing the artery between the fingers4 ,after a similar preparation of a limb1 a ligature was placed around the vein2 a tube was then inserted into it2 it was found that the blood ascended in the tube from the obstructed vein just as high as from the artery4 #cjb4 ,thus we are able to trace the action of the heart from the beginning to the end of the circle4 ,of this circle it is the sole moving power2 but it is a living engine acting in combination with living vessels4 ,the force it exerts is a vital force1 economized by the agency of a vital property communicated to the vessels1 by virtue of which they spontaneously and completely remove all physical obstruction to the progress of the stream through its channels4 #cjc4 ,some ,german physiologists of great eminence1 after a careful and patient observation of the blood1 have satisfied themselves that in addition to the contraction of the heart1 it is necessary to admit a second original and independent motive force1 namely1 a self-moving power inherent in the particles of the blood itself4 ,the blood we know is a living substance4 ,no reason can be assigned why the power of originating motion should not be communicated to such a substance as well as to the muscular fibre1 of which1 indeed1 one constituent of the blood affords the basis4 ,such a power1 if found to be inherent in the particles of the blood1 would explain some phenomena connected with the circulation not yet clearly elucidated2 but the proof of the self-moving power of the blood does not yet seem to be complete4 ,it is1 however1 impossible to explain the phenomena of the circulation1 or to obtain a satisfactory view of some of the other functions of the economy1 without supposing the particles of the blood to be endowed with a vital power of repulsion1 in consequence of which they are prevented from uniting when in contact1 and the fluidity of the mass is maintained4 ,in this account of the powers that move the blood1 no notice has been taken of the physical agents supposed to act as auxiliaries to the heart1 in carrying on the circulation1 such as the suction power of the thorax1 and of the auricles of the heart1 and the capillary attraction of the vessels2 because1 without questioning the existence of such agents1 or denying that advantage may be taken of them1 it seems pretty clear that their influence is but trivial1 and they assumed importance only when the vital endowments of the tissues were not well understood4 #cjd4 ,the ultimate end for which the apparatus of the circulation is constructed1 and for which all its action is exerted1 is to convey arterial blood to the capillary arteries4 ,these vessels are totally distinct in structure and in office from the larger arterial tubes4 ,all the tunics of these minute vessels diminish in thickness and strength as the tubes lessen in size1 but more especially the middle or the fibrous coat2 which1 according to ,wedemeyer1 may still be distinguished by its colour in the transverse section of any vessel whose internal diameter is not less than the tenth of a line2 but that it entirely disappears in vessels too small and too remote to receive the wave of blood in a manifest jet4 ,but while the membranous tunics diminish1 the nervous filaments distributed to them increase3 the smaller and thinner the capillary1 the greater the proportionate quantity of its nervous matter2 and this is most manifest in organs of the greatest irritability4 ,the coats of the capillaries successively becoming thinner and thinner1 at length disappear altogether1 and the vessels ultimately terminate in membraneless canals formed in the substance of the tissues4 ,the blood in the finest capillaries1 says ,wedemeyer1 no longer flows within actual vessels2 it is not contained in tubes whose parietes are formed by a membranous substance distinguishable by its texture and compactness from the adjoining cellular tissue3 it is contained in the different tissues in channels which it forms in them for itself2 and1 under the microscope1 the stream is seen easily and rapidly to work out for itself a new passage in the tissues which it penetrates4 #cje4 ,some of these fine capillaries1 before they entirely lose their membranous tunics1 communicate directly with veins4 ,of the capillaries which terminate by direct communication with veins1 some are large enough to admit of three or four of the red particles of the blood abreast2 the diameter of others is sufficient to admit only of one2 while others are so small that they can transmit nothing but the serum of the blood4 ,as long as the capillary is of sufficient magnitude to receive three or four of the particles abreast1 it is evident that it possesses regular parietes2 but by far the greater number1 before they communicate with veins1 lose altogether their membranous coats4 ,there are no visible openings or pores in the sides or ends of the capillaries by means of which the blood can be extravasated1 preparatory to its being imbibed by the veins4 ,there is nowhere apparent a sudden passage of the arterial into the venous stream2 no abrupt boundary between the division of the two systems4 ,the arterial streamlet winds through long routes1 and describes numerous turns before it assumes the nature and takes the direction of a venous streamlet4 ,the ultimate capillary rarely passes from a large arterial into a large venous branch4 #cjf4 ,the vital power which it has been shown 7#bih7 is possessed by the arterial trunks and branches1 is still more intense in the minute capillaries4 ,if alcohol1 strong acetic acid1 naphtha1 and other stimulating fluids1 be injected into the arteries of a living animal1 it is found that they are not transmitted through the capillaries at all1 or1 at all events1 that they make their way through them with extreme difficulty2 whereas mild1 unirritating fluids pass with rapidity and ease4 ,wedemeyer exposed and divided the main artery in the fore-leg of a horse1 together with the corresponding vein in the shoulder4 ,several syringes-full of tepid water were now injected into the lower end of the artery4 ,the gentlest pressure was sufficient to force the fluid through the capillaries4 ,at each injection the water issued in a full stream from the aperture of the vein1 the flow of the fluid ceasing as soon as the injection was stopped4 ,next1 instead of water1 four syringes-full of pure cold brandy were injected4 ,to propel this fluid through the capillaries1 so as to render its smell and taste perceptible at the aperture of the vein1 required a great degree of pressure2 and when at last the fluid issued from the vein1 it merely trickled in a feeble stream4 ,the experiment being repeated on another horse with vinegar1 six syringes-full of which being injected in rapid succession1 at first this fluid passed as easily as water1 afterwards it flowed with greater difficulty and in a small stream2 before long the force required to propel it was extreme1 and at last the obstruction to its passage became complete1 so that no fluid whatever issued from the vein4 ,these experiments1 whenever repeated1 afforded the same result1 and they demonstrate that the capillaries are capable of being stimulated to contract upon their contents1 and that they can contract with such force as to stop the current4 ,it is manifest that the power by which they do this is vital1 because after death all fluids1 the mildest and the most acrid1 pass through them with equal facility4 #cjg4 ,drs4 ,thompson1 ,philip1 ,hastings1 and others in this country1 have applied stimulants of various kinds to the capillary arteries1 in order to observe with the microscope the changes which the vessels undergo4 ,the results of these experiments1 performed independently1 agree with each other2 and all the observers concur in stating that those results are so obvious and decisive as to admit of no question4 ,wedemeyer1 fully aware of all that had been done on this subject by the ,english physiologists1 repeated their experiments with his usual patience and care1 vigilantly watching the effects with his microscope4 ,his observations completely coincide with those of our countrymen4 ,the circulation being observed in the mesentery of the frog and in the web of its foot1 it was apparent that no change whatever took place in the diameter of the small arteries1 nor in that of the capillaries1 as long as the circulation was allowed to go on in its natural state2 but as soon as stimulants were applied to them1 an alteration of their diameter was visible4 ,alcohol1 without much apparent contraction of the vessels1 stopped the flow of the blood4 ,muriate of soda1 in the course of three or four minutes1 caused the vessels to contract one-fifth of their calibre1 which contraction was followed by dilatation and gradual retardation and stoppage of the blood4 ,ammonia caused immediate and direct dilatation1 and the effect of galvanism was still more striking4 ,in a space of time varying from ten to thirty seconds1 nay1 sometimes immediately after the completion of the galvanic circle1 the vessels contracted1 some a fourth1 others half1 and others three-fourths1 of their calibre4 ,the flow of the blood through the contracted vessels was accelerated4 ,the contraction sometimes lasted a considerable time1 occasionally several hours2 in other instances the contraction ceased in ten minutes1 and the vessels resumed their natural diameter4 ,a second application of galvanism to the same capillaries seldom caused any material contraction4 #cjh4 ,the evidence1 then1 is abundant that stimulants are capable of modifying to a great extent the action of the capillary arteries1 sometimes causing them to contract1 at other times to dilate2 sometimes quickening the flow of blood through them1 at other times retarding it1 and frequently altogether arresting its motion4 ,this contractile power of the capillaries must be a vital endowment1 for no such property is possessed by any substance destitute of life1 and there is satisfactory evidence that it is communicated1 regulated1 and controlled by the organic nerves1 which1 as has been shown1 increase as the size of the vessels and the thickness of their membranous tunics diminish4 ,the powerful influence of these nerves upon the capillary vessels is placed beyond doubt or controversy by the obvious local changes produced in the capillary circulation by sudden1 and even by mental1 impressions1 by the flush of the cheek and the sparkle of the eye1 at a thought conceived or a sound heard2 changes which can be effected1 as far as we have any knowledge1 by no medium excepting that of the nerves4 ,the part performed by electricity1 the physical agent by which it is conceived the nerves operate1 will be considered hereafter4 #cji4 ,exerting upon each other a vital force of repulsion1 under a vital influence derived from the organic nerves1 urged by the vital contraction of the heart1 the particles of the blood reach the extreme capillaries4 ,most of these capillaries terminate 7#cjd7 in canals1 which they work out for themselves in the substance of the tissues4 ,the tissues are endowed with a vital attractive force1 which they exert upon the blood--an elective as well as an attractive force3 for in every part of the body1 in the brain1 the heart1 the lung1 the muscle1 the membrane1 the bone1 each tissue attracts only those constituents of which it is itself composed4 ,thus the common current1 rich in all the proximate constituents of the tissues1 flows out to each4 ,as the current approaches the tissue1 the particles appropriate to the tissue feel its attractive force1 obey it1 quit the stream1 mingle with the substance of the tissue1 become identified with it1 and are changed into its own true and proper nature4 ,meantime1 the particles which are not appropriate to that particular tissue1 not being attracted by it1 do not quit the current1 but passing on1 are borne by other capillaries to other tissues1 to which they are appropriate1 and by which they are apprehended and assimilated1 ,when it has given to the tissues the constituents with which it abounded1 and received from them particles no longer useful1 and which would become noxious1 the blood flows into the veins to be returned by the pulmonic heart to the lung1 where1 parting with the useless and noxious matter it has accumulated1 and1 replenished with new proximate principles1 it returns to the systemic heart1 by which it is again sent back to the tissues4 #caj4 ,particles of blood are seen to quit the current and mingle with the tissues2 particles are seen to quit the tissues and mingle with the current4 ,but all that we can see1 with the best aid we can get1 does but bring us to the confines of the grand operations that go on1 of which we are altogether ignorant4 ,arterial blood is conveyed by the arteries to the capillaries2 but before it has passed from under the influence of the capillaries it has ceased to be arterial blood4 ,arterial blood is conveyed by the carotid artery to the brain2 but the cerebral capillaries do not deposit blood1 but brain4 ,arterial blood is conveyed by its nutrient arteries to bone1 but the osseous capillaries do not deposit blood1 but bone4 ,arterial blood is conveyed by the muscular arteries to muscle1 but the muscular capillaries do not deposit blood1 but muscle4 ,the blood conveyed by the capillaries of brain1 bone1 and muscle is the same1 all comes alike from the systemic heart1 and is alike conveyed to all tissues2 yet in the one it becomes brain1 in the other bone1 and in the third muscle4 ,out of one and the same fluid these living chemists manufacture cuticle1 and membrane1 and muscle1 and brain1 and bone2 the tears1 the wax1 the fat1 the saliva1 the gastric juice1 the milk1 the bile1 all the fluids1 and all the solids of the body4 #caa4 ,and they do still more2 for they are architects as well as chemists2 after they have manufactured the tissue1 they construct the organ4 ,the capillaries of the eye not only form its different membranes and humours1 but arrange them in such a manner as to constitute the optical instrument2 and the capillaries of the brain not only form cerebral matter1 but build it up into the instrument of sensation1 thought1 and motion4 #cab4 ,the practical applications of these phenomena are numerous and most important2 but they can be clearly and impressively stated only when the operation of the physical agents which influence the circulation1 and which proportionally affect life and health1 has been explained4 ,,footnotes4 #a ,computationi in alimentis faciend hanc formam esse ,ulpianus scribit1 ut prim tate usque ad annum vicesimum quantitas alimentorum triginta annorum computetur1 ejusque quantitatis ,falcidia prstetur3 ab annis ver viginti usque ad annum vicesimumquintum annorum viginti octo3 ab annis vigintiquinque usque ad annos triginta1 annorum vigintiquinque3 ab annis triginta usque ad annos trigintaquinque annorum viginti duo2 ab annis trigintaquinque usque ad annos quadraginta annorum viginti3 ab annis quadraginta usque ad annos quinquaginta tot annorum computatio fit quot tate ejus ad annum sexagesimum deerit1 remisso uno anno3 ab anno ver quinquagesimo usque ad annum quinquagesimumquintum annorum novem3 ab annis quinquagintaquinque usque ad annum sexagesimum annorum septem3 ab annis sexaginta1 cujuscunque tatis sit1 annorum quinque2 eoque nos jure uti ,ulpianus ait1 et circa compu tationem ususfructus faciendam4 ,solitum est tamen prim tate usque ad annum trigesimum computationem annorum triginta fieri3 ab annis ver triginta tot annorum computationem inire1 quot ad annum sexagesimum deesse videntur2 nunquam ergo amplius quam triginta aunorum computatio initur4 ,sic denique1 et si ,reipublic ususfructus egetur1 sive simpliciter1 sive ad ludos1 triginta annorum computatio fit4 ,si quis ex heredibus rem propriam esse contendat1 deinde hereditariam esse convincatur3 quidem putant ejus quoque ,falcidiam non posse retineri2 qui nihil intersit1 subtraxerit an hereditariam esse negaverit4 ,quod ,ulpianus rect improbat4 7,vide ,justin4 ,pandect4 lib4 #ce1 tit4 #b1 ad ,legem ,falcidiam47 #b ,which maximum is a little above the highest point hitherto any where attained4 #c ,hence in the preparation of jelly as an article of diet1 the parts of young animals1 as the feet of the calf1 are principally employed2 whereas soups made from beef contain a large proportion of albumen1 while in those made from veal the proportion of jelly preponderates4 #d ,treatise on ,ligaments1 by ,bransby ,b4 ,cooper1 ,esq4 #e ,for these illustrations ,i am indebted to ,mr4 ,lister1 who has been so kind as to make drawings of the objects for me4 #f ,whenever there is any interruption to the ordinary flow of the circulating fluids1 the powers of the anastomosing circulation are capable of being increased to a surprising extent4 ,the aorta itself has frequently been tied in animals of considerable size without destroying life2 in the human body it has also been found obliterated by disease in different parts of its course1 in one case as high as the termination of its curvature4 ,in the cure for aneurism the external iliac artery has been tied by ,mr4 ,abernethy with success2 the subclavian artery below the clavicle by ,mr4 ,keate2 the common carotid by ,sir ,astley ,cooper2 the subclavian artery above the clavicle by ,mr4 ,ramsden2 the internal iliac artery by ,dr4 ,stevens2 the arteria innominata by ,dr4 ,mott1 of ,new ,york2 and lastly1 the abdominal aorta itself1 by ,sir ,a4 ,cooper4 ,mr4 ,grainger tied the abdominal aorta of a dog2 when the animal had recovered from that operation1 the carotids and the great trunks of the anterior extremities were tied3 in this manner the whole course of the circulation was altered4 ,the dog1 which was of very large size1 survived all these operations1 and appeared to enjoy its ordinary health4 ,grainger's ,general ,anatomy1 p4 #bea-bec4 #g ,see this matter very ably discussed in ,dr4 ,arnott's excellent work on the ,elements of ,physics1 vol4 i4 ,,end ,,of ,,vol4 ,i4 ,london3 ,printed by ,w4 ,,clowes and ,,sons1 ,stamford ,street4 ,,transcriber',s ,,notes4 #a4 7,figure ,,lxxiv47 was incorrectly labeled as 7,figure ,,lxxvi474 ,this has been corrected4 #b4 ,no ,figure ,,lxx in original book4