,,section-,,cutting3 ,a ,,practical ,,guide ,,to ,,the ,,preparation ,,and ,,mounting ,,of ,,sections ,,for ,,the ,,microscope1 ,,special ,,prominence ,,being ,,given ,,to ,,the ,,subject ,,of ,,animal ,,sections4 ,,by ,,dr4 ,,sylvester ,,marsh4 ,,with ,,illustrations4 ,,reprinted ,,from ,,the ,,london ,,edition1 ,,with ,,notes ,,and ,,an ,,appendix ,,on ,,the ,,selection ,,and ,,care ,,of ,,section ,,knives4 ,,new ,,york3 ,,industrial ,,publication ,,company4 #ahgi4 ---------------------------------------- -------------------------------- ,,preface4 ,if we glance at any of the numerous magazines devoted either wholly or in part to the subject of microscopy1 we shall hardly fail to be struck with the numerous queries relating to ,,section-,,cutting1 which are to be found in its pages4 ,a simple explanation of this wide-spread want is afforded by the fact that the use of the microscope has at the present day extended to 7and is still rapidly spreading amongst7 vast numbers of students1 who1 in many instances1 possess neither the leisure nor the means to refer for information to large and expensive text-books4 ,moreover1 were they actually to consult such works1 they would practically fail to obtain the information of which they are in need1 for the coveted instruction is to be found in those treatises only in a scattered and fragmentary form--no work with which we are acquainted treating of the subject in anything like a detailed manner4 ,to fill this vacuum in the literature of microscopy the present manualette has been prepared4 ,little claim is made to originality1 yet the book is by no means a mere compilation1 but the outcome of long and extensive personal experience in the cutting and mounting of microscopical sections4 ,every process described has been put to the test of actual trial1 so that its worth may confidently be depended upon4 ,many of the little points insisted upon in the ensuing pages will doubtless to the practised microscopist appear superfluous or even puerile2 but a vivid recollection of our own early failures and disappointments assures us that it is just these very minuti of detail which will be found most serviceable in directing and sustaining the faltering footsteps of the tyro4 ,,st4 ,,helens1 ,september1 #ahgh4 ---------------------------------------- -------------------------------- ,,preface ,,to ,,american ,,edition4 -------------- ,dr4 ,marsh's book cannot fail to promote the practical study of histology wherever the ,english language is spoken1 and under ordinary circumstances the students of this country might have been left to the use of the ,london edition4 ,but a careful reading showed that one or two points which are perfectly clear to ,british readers might be a source of doubt and difficulty to students on this side4 ,at the present day in this country histology is a favorite study with very many private students who have no access to teachers or large libraries1 and for the purpose of smoothing their path we have added such information as was obviously desirable4 ,in the hope that these additions will prove of value1 we submit the book to ,american readers4 ,,new ,,york1 ,january1 #ahgi4 ---------------------------------------- -------------------------------- ,,contents4 ------- ,,part ,i4 ,introduction #aa ,on ,cutting ,unprepared ,vegetable ,tissues #ab ,on ,cutting ,unprepared ,animal ,tissues #ac ,preparation of ,vegetable ,tissues #ae ,preparation of ,animal ,tissues #af ,special ,methods of ,hardening #ai ,cutting ,hardened ,tissues by ,hand #ai ,microtome #bj ther ,microtome #bd ,section-,knife #bd ,imbedding in ,paraffine for ,microtome #bf ,employment of ,microtome #bi ,staining ,agents #ca ,carmine ,staining #cb ,mounting ,media #cf ,mounting in ,glycerine #ch ,uses of ,freezing ,microtome #db ,employment of ,freezing ,microtome #dc ,logwood ,staining #dg ,absolute ,alcohol #ej ,clove ,oil #ea ,canada ,balsam #ea ,mounting in ,balsam #ec ,finishing the ,slide #ee ,,part ,,ii4 ,special ,methods #eg ,bone #eg ,brain #ei ,cartilage #fj ,coffee ,berry #fb ,fat #fc ,hair #fc ,horn1 etc4 #fd ,intestine #fd ,liver #fe ,lung #fe ,muscle #ff ,orange-peel #fg ,ovary #fg ,porcupine ,quill #fg ,potato #fg ,rush #fh ,skin #fh ,spinal ,cord #fi ,sponge #ga ,stomach #ga ,tongue #ga ,vegetable ,ivory #gb ,wood #gb ,note ,a1 #ge ,note ,b1 #ge ,note ,c1 #gf ,note ,d1 #gf ,note ,e1 #gf ,note ,f1 #gg ,note ,g1 #gg ,note ,h1 #ic ,note ,i1 #id ,index ---------------------------------------- -------------------------------- ,,section-,,cutting4 -------------- ,,part ,i4 #a4 ,introduction4--,many of the most interesting objects with which the microscopist has to deal1 cannot be made to reveal their beauty or minute structure until they have been cut into slices or sections1 of such a degree of thinness as to render them transparent1 and thus permit of their examination by transmitted light1 with objectives of varying power4 ,unfortunately1 however1 very few of the objects of this class are1 in their natural condition1 in a suitable state to be submitted to this method of procedure4 ,some are of such a soft and yielding nature that any attempt to cut them is an utter failure1 for in place of a perfect section being obtained1 nothing remains upon the knife but a mass of diffluent pulp2 others1 again1 are of such density as to resist the action of any cutting instrument4 ,it is evident1 therefore1 that nothing can be done with such refractory materials until1 by subjection to appropriate methods of preparation1 they shall have been reduced to such a consistence as to render them suitable for cutting4 ,how this is to be accomplished will depend entirely upon the physical and chemical nature of the substance to be operated upon4 ,as the various objects differ so widely from each other in these respects1 so must the methods of preparation suitable to each also vary4 ,it is clear1 therefore1 that no general directions for attaining this end can be given which would be of any practical value4 ,it is possible1 however1 and very convenient1 to arrange the various objects into groups or classes1 to the treatment of each of which certain general rules are applicable2 but there will still remain a comparatively numerous series of objects whose individual peculiarities of structure will demand for them correspondingly special methods of preparation4 ,when such objects come to be spoken of1 the particular treatment most suitable to each will also be noticed4 #b4 ,on ,cutting unprepared ,vegetable ,tissues4--,there are some few substances1 however1 which may with more or less success be cut into sections whilst in their natural condition4 ,such objects are to be found in the vegetable world in certain kinds of leaves and allied structures1 whilst in the animal kingdom they are principally represented by the various internal organs of man and the lower animals4 ,special directions are given in text-books for the preparation of sections of leaves and similar substances4 ,for instance1 it is recommended to lay the leaf1 etc41 on a piece of fine cork1 and with a sharp knife to shave off thin slices1 cutting down upon the cork4 ,another plan is to place the leaf1 etc41 between two thin layers of cork1 and cut through the mass4 ,no method1 however1 is at once so simple and successful as the process of imbedding in paraffine4 ,to do this1 it is necessary to make a paper mould by twisting a strip of stout writing paper round a ruler1 and turning-in the paper over the end of the ruler4 ,this mould1 the height of which may vary from an inch to an inch and a half1 should now be about half filled with melted paraffine mixture 7 #aa71 the leaf or other object plunged into it1 and held in position by small forceps till the paraffine has become sufficiently solidified to yield it a support4 ,more of the paraffine mixture is now poured in until the specimen is thoroughly imbedded2 the whole is to be put away in a cold place for an hour or so1 when the mass will be found sufficiently firm to be cut with ease4 ,sections may be made with a razor kept constantly wetted with water1 or1 if the preservation of colour be no object1 methylated spirit may be employed for the purpose4 ,as the subsequent treatment of such sections in no wise differs from that required by those cut in the microtome1 we shall defer its consideration until that method of section has been described 7 #ab74 #c4 ,on ,cutting unprepared ,animal ,tissues4--,for the cutting of fresh animal tissues several plans may be followed4 ,thus1 if a section of only very limited area be required1 it may be obtained by snipping a piece off the tissue with a pair of bent scissors1 which1 for this purpose1 are so made that the blades are curved on the flat 7,carpenter74 ,if this be carefully performed it will be found that a large portion of the section 7particularly at the circumference7 so obtained will be sufficiently thin for examination4 ,if a larger section be desired1 an attempt may be made to cut it with a very sharp scalpel or razor1 the blade of which whilst in use must be kept flooded with water1 or spirit1 the latter of which is to be preferred4 ,recourse may also be had to ,valentin's knife4 ,this consists of two long1 narrow blades1 running parallel to each other1 the distance at which the blades are held apart1 and which1 of course1 determines the thickness of the section1 being regulated by means of a fine screw passing through both blades4 ,a milled head attached to this screw gives a ready means of opening or closing the blades1 so as to bring them to the desired degree of approximation4 ,the method of using the knife is very simple4 ,after having 8set0 the blades at the desired distance apart by means of the milled head1 the tissue to be cut is held in the left hand immersed in a basin of water4 ,the knife is now steadily and with a rapid motion drawn through the tissue1 care being taken that the cut is made in such a manner that the blades move from heel to point4 ,by slightly separating the blades and gently shaking them in the water1 the section at once becomes disengaged4 ,after use1 the blades must be thoroughly dried1 when they may be smeared with some oil which does not readily oxidize4 ,for this purpose1 a very suitable oil is that known as 8,rangoon40#a ,though it has been deemed advisable briefly to describe the preceding methods of cutting unhardened tissues1 it will be found that for the purposes of the ordinary microscopical student sections so obtained are of very little value4 ,they are always of very limited dimensions1 seldom of uniform thickness1 and often so extremely friable as to render it very difficult and frequently impossible to submit them with safety to such further treatment as is necessary to fit them for being mounted as permanent objects4 ,this method of section-cutting1 however1 is not without its uses1 for by its means the medical practitioner is provided with a simple and ready method of roughly investigating the structure of morbid tissues1 whilst to the general student it furnishes an easy means of making a cursory examination of certain substances1 in order that he may determine whether it be worth his while to subject them to some of those various processes of hardening hereafter to be described4 ,footnote #a3 ,note ,a4 #d4 ,preparation of ,vegetable ,tissues4--,let us now pass to a brief consideration of the methods usually adopted for preparing the various objects for easy section4 ,in the case of vegetable tissues1 not only do we1 as a rule1 find their texture of too great density to be readily cut in their natural condition1 but they also contain much resinous and starchy matter1 of which it is highly desirable to get rid4 ,in order to do this we first cut the substance 7say a stem or root7 into small pieces1 which are to be placed in water for three or four days1 by which time all the soluble gummy matters will have disappeared4 ,the pieces are now transferred to a wide-necked bottle1 containing methylated spirit1#b which1 in the course of a few days1 will dissolve out all the resin1 etc4 ,many kinds of woody tissue are by these processes reduced to a fit condition for immediate cutting2 others1 however1 are so hard as to render it necessary to give them another soaking for some hours in water1 to bring them to a sufficient degree of softness to cut easily4 ,if the wood 7as in some few refractory cases will happen7 be still too hard for section1 a short immersion in warm1 or if necessary1 in boiling water1 will not fail effectually to soften it4 ,the treatment of such members of the vegetable division as require peculiar methods1 will be found described in future pages4 ,footnote #b3 ,note ,b4 #e4 ,preparation of ,animal ,tissues4--,animal tissues differ from one another so greatly1 both in consistence and in chemical composition1 as well as in their degree of natural hardness1 that no general rules can be given which would be applicable to the preparation of the whole class4 ,such as are of any considerable degree of hardness1 as horn and kindred structures1 must be treated much in the same manner as the denser varieties of wood1 viz41 by more or less prolonged immersion in water--cold1 hot1 or boiling4 ,those which are of extreme hardness1 as bones and teeth1 can be cut only by following certain special methods1 full details of which will be found in the ,second ,part of this work 7 #bf74 ,many1 and indeed the vast majority of animal tissues1 offer a direct contrast in point of hardness to those we have just been considering4 ,all the internal organs of the body are1 when freshly removed1 of much too soft a nature to permit1 when in their unprepared condition1 of easy or perfect cutting4 ,it is upon bringing them to that critical degree of hardness1 which is often so difficult to attain1 that the chief secret of successful section-cutting depends2 for unless the hardening process has been carried up to1 but not beyond1 a given point1 which varies with different tissues1 the operator1 however dexterous1 will fail to obtain satisfactory sections4 ,for1 if the hardening has fallen short of this critical point1 he is1 to some extent1 in the same position as if he were dealing with unhardened tissues2 whilst1 if this point has been exceeded1 the tissue will have become so brittle as to crumble before the knife4 ,for the purpose of hardening animal tissues1 the student has at his command two principal agents1 namely1 alcohol and chromic acid1 each of which possesses advantages of its own1 but the use of each of which is also attended by its own inconveniences4 ,thus1 by the use of alcohol1 there is very much less risk of overhardening the specimen than if chromic acid had been employed4 ,alcohol1 however1 though a capital indurating agent in some instances1 does not answer so well in many others4 ,chromic acid is1 therefore1 to be preferred for general use4 ,it is1 however1 a very delicate agent to manage1 for unless the greatest care be taken it is exceedingly likely to overharden tissues submitted to its action1 and when this happens the specimen becomes utterly useless for cutting1 as there is no known means of removing the extreme brittleness which it has acquired4 ,by taking the precautions now to be given1 this overhardening may generally be avoided4 ,let us harden a portion of some viscus1 say the kidney1 for instance4 ,suppose we cut from the organ five or six small pieces 7from half to three-quarters of an inch square1 not larger74 ,these must be placed in a mixture of equal parts of methylated spirit and water for three days1 at the end of which period they may be transferred to a solution of chromic acid1 made by dissolving twenty grains of the pure acid in sixteen ounces of distilled water4 ,the solution should be kept in a wide-necked bottle furnished with a glass stopper4 ,at the expiration of seven days1 pour off the solution and replace it by fresh4 ,at the end of another week1 carefully examine the immersed tissues1 and by means of a sharp razor see if they have acquired the necessary degree of hardness to allow of a section of moderate thinness being made4 ,if so1 remove the pieces and put them into a stoppered bottle containing from six to eight ounces of methylated spirit4 ,if1 however1 the hardening be found not to be sufficiently advanced1 the chromic acid solution is to be poured off and again replaced by fresh4 ,it will now be necessary to examine the tissues at intervals of about two days1 until they are found to be sufficiently hard1 when they must be transferred to the spirit4 ,under no circumstances1 however1 should they be permitted to remain in the chromic acid longer than the end of the third week1 and though they should at this time appear not to have undergone sufficient induration1 yet it will be advisable to transfer them to the methylated spirit1 which in a short time will safely complete the process of hardening1 without any risk being run of the tissue becoming ruinously brittle4 ,it will be noticed1 that when the specimens have been transferred to spirit1 the latter will in a day or two become of a deep yellow color1 whilst a thick flocculent deposit falls to the bottom of the bottle4 ,the tissues should then be removed1 the bottle emptied and well washed1 and1 being refilled with clean spirit1 the preparations are again to be replaced4 ,this may occasionally be repeated1 until the spirit becomes and remains perfectly bright and clear4 ,the specimens are then ready for section4 #f4 ,special ,methods of ,hardening4--,the brain 7 #bg71 spinal cord 7 #dc71 liver 7 #cd71 and several other organs1 etc41 require special methods of hardening1 details of which will be found in the paragraph devoted to each4 ,in the case of injected preparations1 the best plan is to harden them in alcohol from the outset1 beginning with weak spirit1 and gradually increasing the strength as the hardening proceeds4 ,when the object has been injected with ,prussian blue1 a few drops of hydrochloric acid should be added to the alcohol to fix the color4 ,it may here be observed1 that specimens of morbid tissues require1 as a general rule1 a shorter immersion in chromic acid solution than healthy tissues do4 ,a very small degree of overhardening speedily renders them brittle and useless4 ,they should1 therefore1 be removed from the acid medium at the end of ten days or a fortnight1 and their further hardening carried on by means of alcohol4 #g4 ,cutting ,hardened ,tissues by ,hand4--,our material being now reduced to a fit condition for cutting1 let us proceed to consider the several methods by which this may be effected4 ,the readiest and most simple plan1 if the piece be large enough1 is to hold it in the left hand1 and1 having brought the surface to a perfect level by cutting off several rather thick slices1 endeavor to cut a thin section by the aid of a very sharp razor1 the blade of which must be kept well flooded with spirit4 ,as in the use of ,valentin's knife1 so here1 great care must be taken steadily to draw the blade across the tissue1 every effort being made to avoid pushing the knife1 else the section will be torn off1 instead of being cut4 ,though this method#c is of very great importance for many purposes1 yet a considerable degree of manipulative skill is required to enable the operator to obtain anything like perfect sections by its means1 and1 unfortunately1 this skill is acquired by very few persons indeed1 even after much practice4 ,if the piece which it is desired to cut be too small to be conveniently held in the hand1 it may be imbedded in paraffine in the manner already described 7 #c74 ,a very simple imbedding agent1 and one of the greatest practical value1 is a strong solution of gum arabic1 which1 upon being dehydrated either by ordinary drying or the action of alcohol1 soon acquires such a degree of hardness as to permit it 7with the imbedded tissue7 to be cut with ease4 ,as this method of imbedding1 however1 is most frequently resorted to where1 by its means1 special difficulties have to be overcome1 a full description of the process 7 #ce7 will be deferred until such special cases come to be spoken of4 ,footnote #c3 ,note ,c4 #h4 ,microtome4--,although the preceding plans may be sufficient to answer all his requirements1 if the student wishes to obtain only one or two sections of small dimensions1 of a given object1 if he requires a number of such sections he will find these methods fail him1 for even though by practice he may have attained to considerable aptitude in the use of the knife1 it will still unquestionably happen that the vast majority of his sections will be more or less imperfect4 ,if1 therefore1 it be desired to procure a number of perfect sections1 of equable thickness and large area1 it is absolutely necessary to resort to the use of some form or other of microtome1 or section-cutter4 ,this instrument1 in its simplest form1 merely consists of a stout brass tube closed at one end1 and being by the other fixed at right angles into a smooth plate of metal4 ,a plug or disk of brass1 accurately fitting the interior of the tube1 is acted upon by a fine threaded screw piercing the base of the tube1 and by means of which the plug1 and any object it may support1 can be elevated at pleasure4 ,the object by this means being made gradually to rise out of the tube1 sections are cut from it by simply gliding a sharp knife along the smooth cutting-plate1 and hence across the specimen4 ,any intelligent worker in brass would make an instrument of this kind at a very small cost1 and although perhaps it might lack the finish of an instrument bought at the optician's1 it would1 if accurately made1 do its work as well as the most complicated and expensive4 ,if1 however1 the student resolves to purchase a microtome1 there are a variety of forms in the market from which he may choose4 ,a few hints may perhaps be of service in enabling him to make a judicious selection4 ,at the outset we may say that unless the student intends to devote himself solely to the production of sections of wood1 etc41 he ought not to procure one of those forms of microtome known as wood section-cutters1 in which the object to be cut is held in position in the tube by means of a binding screw which pierces its side4#d ,although these machines are all that can be desired for cutting hard bodies1 they are not so suitable for soft ones4 ,the chief points to be attended to in selecting a microtome are1 7#a7 that the cutting-plate of the instrument be made of glass1 or in default of this1 of very hard metal of the most perfect smoothness2#e 7#b7 that the diameter of the tube be neither too large nor too small--it ought not to be less than #e_/h-;in41 or greater than #a inch2#f 7#c7 that the screw1 which should be fine and well cut1 be provided with a graduated head2 7#d7 that there be some kind of index by which fractional portions of a revolution of the screw may be measured2 and 7#e7 that the plug fit the tube of the microtome so accurately that when melted paraffine1 gum1 or other imbedding agent be poured into it1 it may not find its way between the plug and side of the tube 7 #ah74 ,it often happens in cutting tissues imbedded in paraffine1 that the pressure of the knife causes the cylinder of the imbedding agent to twist round in the tube of the machine1 and so cause considerable difficulty and annoyance4 ,this evil is usually met by running a deep groove across the upper surface of the plug1 and into this the paraffine sinks1 and so is prevented from rotating4 ,it will be found1 moreover1 that another difficulty of a kindred1 though much more serious character1 will frequently be encountered4 ,during section the paraffine has a tendency not only to rotate1 but also to become loosened from the subjacent plug1 and to rise in the tube of the microtome4 ,when this happens the power to cut sections of uniform thickness has completely gone1 for some will now be found to be many times thicker than others2 in fact1 the irregularity in this respect soon becomes so monstrous as to render it useless to prolong the sitting4 ,in the ordinary run of microtomes no provision seems to have been made to meet this difficulty1 and for this reason many instruments1 of otherwise great merit1 have their efficiency seriously impaired4 ,fortunately1 this imperfection is easily remedied1 all that is required being that the upper surface of the plug should be furnished with some kind of projection1 having at its summit a table-like expansion1 as shown at ,a in the figure4 ,the imbedding paraffine1 by penetrating beneath and around this1 becomes firmly attached to the plug1 and thus all risk of its rising is effectually avoided4 ,if the student wishes to secure a really first-class instrument1 none can be so confidently recommended as the freezing microtome of ,professor ,rutherford4 ,in addition to its being the best instrument for carrying out the freezing method 7 #ah71 this machine is equally effective for cutting tissues imbedded in paraffine1 or any of the other agents used for that purpose2 indeed1 whatever work a microtome can do1 this one will perform4 ,footnote #d3 ,note ,d4 ,footnote #e3 ,note ,e4 ,footnote #f3 ,note ,f4 ,illustration3 ,,section ,,of ,,microtome-,,tube ,,showing ,,arrangement 7,a7 ,,to ,,prevent 8,,rise0 ,,of ,,paraffine4 #i4 ther ,microtome4--,a word here as to freezing microtomes1 where the agent used is ther4 ,such as have fallen under our notice have not answered the expectations we were justly entitled to form of them4 ,that it is possible to freeze a piece of tissue by their use is undeniable1 but it is1 as a rule1 at an expenditure of such a quantity of ther 7only the very best of which must be used7 as to constitute it a very expensive proceeding4 ,another serious disadvantage they possess is1 that if the supply of ther be intermitted for only a very short time1 the already frozen tissue thaws with great and most inconvenient rapidity4 #aj4 ,section-,knife4--,of not less importance than the microtome is the section-knife1 to be used in conjunction with it4 ,how perfect soever the former1 and whatever the dexterity of the operator1 unless he be provided with a suitable and well-made knife1 he will never succeed in obtaining satisfactory results4 ,as to the most desirable size of the knife1 much difference of opinion seems to exist1 section knives varying in this respect from a blade of extreme shortness to one which fell under our observation1 in which the portentous length of thirteen inches was attained4 ,what advantages were to be expected by prolonging the blade to this extravagant length1 must remain an inscrutable mystery to all save its designer4 ,concerning the shape of the knife1 it is frequently advised that the surface which has to glide along the cutting-plate of the microtome should be ground flat4 ,a most unsuitable arrangement1 as a very little actual experience of section-cutting will speedily demonstrate4 ,after many unsuccessful attempts to obtain a really good and reliable section-knife1 we determined to have one specially made1 which1 as it has proved everything that could be desired1 merits a brief description4 ,it is of the utmost importance that the blade be made of good and well-tempered steel1 not only that it may be capable of receiving an edge of the most exquisite keenness1 but also that it may retain it4 ,the knife of which we speak 7and which was made by ,mr4 ,gardner1 of ,south ,bridge1 ,edinburgh7 is furnished with a blade four inches long1 and #g_/h-;inch broad1 set into a square handle of boxwood1 also four inches in length4 ,the thickness of the blade at the back is not quite #a_/d-;inch1 while both of its surfaces are slightly hollow ground4 ,it is essentially necessary that the back and edge of the blade be strictly parallel to each other1 otherwise the knife1 when in use1 will have such a tendency to tilt over as to render its management extremely difficult4 ,it is very easy to discover if this condition be fulfilled1 for if on carefully laying the flat of the blade upon a piece of level glass1 every portion of both back and edge are found to be in close contact with it1 the knife may in this respect be considered perfect4 ,every student who aspires to be a successful section-cutter should provide himself with a good ,turkey oilstone1 and learn to use it4 ,he should also possess a razor strop1 as it will be in constant requisition4#g ,it may here be remarked that though razors1 as a rule1 are unsuitable for use with the microtome from want of uniformity in the thickness of their blades1 yet1 if only a small object is to be cut--for instance1 a thin root or stem--very good results may be obtained from their use1 especially if one of the old-fashioned make1 having a thick back and slightly concave surfaces1 be employed4 #aa4 ,imbedding in ,paraffine for ,microtome4--,having described at some length the various instruments necessary for section-cutting1 we will now consider how they are to be used4 ,let us endeavor to cut some sections--say of a piece of kidney--and in so doing we will adopt the 8paraffine0 method of imbedding4 ,ordinary paraffine1 however1 when used alone1 is rather too hard for our purpose4 ,in order1 therefore1 to bring it to a suitable consistence1 it must be mixed with one-fifth its weight of common unsalted lard1 a gentle heat applied1 and the two thoroughly stirred together4 ,a quantity of this should be prepared1 so that it may always be ready when wanted--it is very conveniently kept in an ointment pot or preserve jar1 the top of the latter being well covered1 to keep out the dust4 ,when it is intended to use this mixture for the purpose of imbedding1 only just about the quantity required should be melted2 for in doing this it is advisable to use as low a degree of heat as possible1 not only to prevent injury to the tissue to be imbedded1 but also that the paraffine when cooling may not undergo such an amount of contraction as to cause it to shrink from the sides of the microtome-tube4 ,it is therefore a good plan to effect the melting in a water-bath1 a simple kind of which1 something after the fashion of a glue-pot1 would be made for a few pence by any tinman4 ,footnote #g3 ,see ,note ,g4 ,the kidney which we are about to cut has1 of course1 gone through the process of hardening already described 7 #e71 and is now preserved in spirit4 ,a small piece1 say half an inch square1 is selected1 removed with forceps1 and placed on a bit of blotting paper1 when the surface of the tissue will rapidly become dry 7only the surface must be allowed to dry74 ,it is the usual plan now to proceed at once to imbed it in the melted paraffine4 ,this is a most undesirable step1 and gives rise at a later stage of our proceedings to a great amount of trouble and annoyance1 for after sections have been cut from a tissue so imbedded it will be found that portions of paraffine adhere to their edges with such tenacity that in the case of many of them there is no effectual method of removing the paraffine1 short of soaking the sections in warm ther2 a very objectionable proceeding1 for though the ther will undoubtedly remove the paraffine1 it will also dissolve out any fatty matters which the section itself may naturally contain4 ,all this annoyance may be prevented by subjecting the tissue to a simple preparatory treatment before it is imbedded in the paraffine4 ,for this purpose prepare a very weak solution of gum arabic in water--twenty grains to the ounce4 ,into this1 by means of the forceps1 dip for a few moments the already surface-dried tissue1 taking special care not to squeeze it1 or the pressure will cause the spirit from its interior to remoisten the surface1 which would prevent the gum from adhering4 ,we shall see the value of this a little later on4 ,remove the tissue from the solution on to blotting paper1 when the superfluous gum will speedily drain off1 and in two or three minutes the surface will have become quite glazy and dry4 ,having melted some paraffine mixture in the water-bath1 the tissue held in the forceps must be plunged for an instant into the heated liquid and immediately withdrawn1 when the crust of paraffine with which it is enveloped will promptly harden4 ,whilst this is taking place we may make ready the microtome4 ,having by means of the milled head or handle depressed the plug in the tube so as to leave a free opening about an inch deep at its upper end1 we must pour in the melted paraffine1 which by this time will have become a little cooler1 until the cavity be about half filled4 ,the prepared tissue must now be introduced1 care being taken to place it in such a position that the sections may be cut in the desired direction4 ,the tissue must1 if necessary1 be held in position with forceps or a needle point1 till the imbedding material becomes hard enough to give it due support4 ,it is here to be remembered that it will not be advisable to place the tissue in the centre of the tube--it will be much more easily cut if placed rather nearer to that edge of the tube which is situated next the operator in the act of cutting4 ,more paraffine is to be slowly added1 until the tissue is completely covered2 even after this still more should be added1 for it will be found that in cooling the paraffine shrinks so as to leave a cup-shaped depression in its centre1 whereby portions of the tissue which were previously covered are again laid bare4 ,the best method of preventing this is to use the paraffine at as low a temperature as possible1 and to use plenty of it4 ,the microtome1 with its contents1 must now be removed to a cool place1 when the paraffine will soon become solidified4 ,whilst this is being accomplished we may make our further preparations4 ,the first thing we require will be a large basin1 full of freshly-filtered water1 and provided with a cover4 ,a small beaker of methylated spirit1 with a dipping rod or pipette1 will also be necessary4 ,we must now see that the section-knife is in thorough order1 to ensure which it will be advisable to give it a few turns on the strop4 ,an ordinary razor will also be of service4 #ab4 ,employment of ,microtome4--,the paraffine being sufficiently hard1 we will clamp the microtome on to the table1 and seat ourselves on a chair of convenient height before it4 ,to our right stand the basin of water1 razor1 and section-knife2 the beaker of spirit to the left1 and a cloth on our knee4 ,a few turns of the microtome screw having brought the paraffine to the surface1 a thick slice is to be cut off1 and this repeated until the imbedded tissue comes into view4 ,this preliminary work had best be done with the razor1 as it is needless to subject our section-knife to unnecessary wear and tear4 ,by a fractional revolution of the screw the tissue is now slightly elevated1 and with the pipette held in the left hand1 a large drop of spirit is to be let fall upon its surface4 ,the section-knife1 grasped firmly but lightly in the right hand1 is to be laid flat upon the cutting-plate of the machine1 so as to occupy the diagonal position shown in the figure4 ,two fingers of the left hand are now laid gently upon the back of the blade1 so as to give it an equable support1 whilst the knife with a rapid motion is pushed in the combined direction of forwards and to the left1 so that the blade in cutting the tissue will pass through it from point to heel4 ,thus it will be observed that the stroke of the knife is from the operator--a far easier and more effective mode of cutting than the reverse plan4 ,the blade of the knife1 having the section just cut1 either floating in a small pool of spirit on its surface or adhering thereto1 must now be immersed in the basin of water1 when by a little very gentle agitation of the knife the section will be floated off4 ,and now we shall find the great practical value of immersing the tissue in gum before imbedding1 for no sooner is the section disengaged from the knife than the thin film of gum which separates the paraffine from it becomes dissolved1 and the section will be observed gradually to subside to the bottom1 leaving the paraffine floating upon the surface4 ,after carefully wiping the knife from all shreds of paraffine1 the microtome screw must again be partially revolved1 more spirit applied to the tissue1 and another section being cut1 it must be transferred to the water as before1 and so on1 until a sufficient number of sections have been obtained4 ,as to how thin the sections should be cut1 no general directions can be given2 each case must be regulated by its own conditions4 ,the denser the tissue1 the thinner should the section be2 whilst certain substances of loose and spongy texture do not require the sections to be particularly thin--it may be said1 however1 in a general way that sections1 and especially animal ones1 cannot be cut too thin so long as they remain perfect and entire4 ,if ,professor ,rutherford's microtome 7as made by ,gardner7 be employed1 the head of the screw will be found to be graduated into divisions of slightly unequal value2 the sections will therefore be marked by corresponding variations of thickness1 so that amongst a number cut1 there must be many of the exact thickness to meet the requirements of any individual case4 ,illustration3 ,,diagram ,,showing ,,diagonal ,,position ,,of ,,knife ,,in ,,commencing ,,to ,,make ,a ,,section4 #ac4 ,staining ,agents4--,before proceeding to mount the sections which have just been cut1 it will be very advisable that they should be submitted to the action of some staining fluid1 in order to render more clear and distinct their minute structure4 ,organic substances possess the property of being able to absorb various colouring matters from their solution1 and to incorporate such colour into their own texture4 ,this power of attraction is not1 however1 possessed by all substances indiscriminately1 or to an equal extent4 ,some possess it in a high degree1 while others appear to be nearly1 if not entirely1 devoid of such power4 ,hence it follows1 that if we immerse an organic tissue 7one of our sections1 for instance7 of complex structure1 in a suitable staining fluid1 the tissue will not become stained in an even and uniform manner throughout1 but the several portions of it will receive varying depths of colour in accordance with the varying attractive power of its several constituents4 ,by this means we are enabled in stained sections to discriminate by their difference of shade1 minute and delicate structures1 which in the unstained condition it would be difficult and often impossible to differentiate4 ,for the purpose of section-staining there are many agents in use1 the most generally suitable being carmine1 logwood 7 #ai71 and aniline blue 7 #bg72 whilst for special purposes chloride of gold 7 #bh71 pyrogallate of iron 7 #bh71 and several others are all of much value4 #ad4 ,carmine ,staining4--,in the case of animal sections1 carmine is1 as a rule1 to be selected1 giving as it does most satisfactory and beautiful results4 ,tissues may be stained with carmine by two different plans3 in the first1 a strong solution is used1 and the tissue subjected to its action for a very short period only1 whilst in the latter only very weak solutions are employed1 the time of immersion being considerably prolonged4 ,the rapid method1 however1 is not to be recommended1 for the strong carmine acts so powerfully upon the tissue as to give the various elements comprising it no time1 as it were1 to exercise their power of quantitive selection1 but involves the whole in one uniform degree of shadeless colour4 ,by adopting the gradual method much better results are obtained1 each portion of the tissue being now at liberty to acquire its own particular shade4 ,amongst the various formul for the preparation of carmine fluid1 none can be so safely followed as that devised by ,dr4 ,lionel ,beale4 ,it runs thus3--,place ten grains of the finest carmine in a test tube1 add thirty minims of strong liquor ammonia1 boil1 add two ounces of distilled water1 and filter2 then add two ounces of glycerine1 and half an ounce of rectified spirit--this solution ought to be kept in a well stoppered bottle4 ,the best vessels in which to stain sections are small jars of white porcelain1 capable of holding about two fluid ounces1 and furnished with lids--they are much preferable to beakers or watch glasses1 for owing to the white background which they afford it is very easy to watch how the staining is proceeding4 ,the carmine solution which we have just described is both too strong and of too great density to be used in its pure state4 ,it will1 therefore1 require to be diluted with distilled water before use--the most useful degree of dilution being attained by adding one part of stain to seven of water4 ,sections may be placed in this solution for twenty-four hours1 in which time they will usually be found to have acquired a sufficient depth of colour4 ,if1 however1 the tissue be unusually difficult to stain1 the time of immersion may be doubled1 or still further prolonged1 without detriment to the section4 ,illustration3 ,,section ,,spoon4 ,having prepared and filtered some of this dilute solution1 say an ounce1 let us proceed to stain with it those sections which we left in the basin of water 7 #ab74 ,here we are at once met by a practical difficulty4 ,how are the sections to be transferred from one vessel to the other8 ,this is ordinarily effected by means of a soft camel's-hair pencil4 ,it is a method1 however1 open to grave objections1 for the sections so curl around the brush1 and get entangled amidst its hairs1 that1 notwithstanding every care1 valuable sections not unfrequently become torn during transit4 ,every difficulty at once vanishes if we substitute for the brush a small implement1 which any one can readily make for himself4 ,all that is necessary is to take a strip of ,german-silver1 or copper1 of the thickness of stout cardboard1 and about seven inches in length by five-eighths of an inch in breadth4 ,the sharp angles are to be filed off and the edges carefully smoothed1 whilst at a distance of five-eighths of an inch from each extremity the end must be turned up so as to form an angle of about #ce4 ,one end must be left plain1 whilst the other1 with the aid of a punch or drill1 is to be pierced with five holes about the thickness of a stocking needle#h 7see ,figure74 ,if we now dip the perforated end of this spoon into the water containing the sections1 and gently agitate it1 the sections will rise from the bottom and float about4 ,the spoon is now brought under one of them1 and being steadily lifted up the water flows downwards through its apertures1 and the section smoothly spreading itself out upon the spoon1 may be gently lifted out of the water1 and on the spoon being dipped into the staining fluid the section at once floats off4 ,by this simple means sections1 however large1 thin or delicate1 may with ease be conveyed from one fluid to another1 with the utmost certainty of their not being injured during the process4 ,the sections having been in the carmine fluid for about twenty-four hours1 as much of the liquor as is possible must be gently poured off1 and its place supplied by a freshly-filtered mixture of five drops of glacial-acetic acid to one ounce of water1 when in a few moments the carmine will become permanently fixed in the tissue1 and the process of staining be complete4 ,footnote #h3 ,dr4 ,klein describes a kind of 8lifter10 made by bending some ,german-silver wire1 but as no drawing accompanies his description1 it is not easy to form a clear idea as to the form of this instrument4 ,in the recent and philosophical work of ,schfer1 a lifter is figured1 which consists of a wire stem1 having attached to its end a spade-like blade4 ,it will be observed that the spoon described in the text differs from this lifter in having one end perforated1 and in this consists the real value of the implement4 #ae4 ,mounting ,media4--,the further treatment of the stained sections will entirely depend upon the nature of the medium in which it is intended to mount them4 ,there are a variety of fluids in use for this purpose1 the principal being dilute alcohol 7 #bf71 dammar1 or ,canada balsam 7 #bb-bc71 and glycerine4 ,these1 however1 cannot be used indiscriminately1 each possessing certain special properties which render it suitable for use with particular classes of objects only4 ,thus1 weak spirit1 having no tendency to increase the transparency of objects1 can advantageously be used with such only as are already perfectly transparent4 ,it is also more suitable for the preservation of vegetable tissues 7when the retention of colour is no object7 than animal1 since with the latter it has a tendency after a while to cause a kind of granular disintegration1 which ultimately destroys much of the usefulness of the preparation4 ,dammar and ,canada balsam1 on the other hand1 possess very great refractive power1 so that they are of great service in mounting objects which require their transparency to be much increased4 ,for this reason they are not well adapted to the preservation of very delicate or transparent tissues 7unless previously stained71 the minute details of which become almost entirely obliterated when mounted in them4 ,the chief advantage possessed by these resinous media is1 that tissues mounted in them undergo no alteration1 even after the lapse of many years4 ,glycerine1 in respect of its clarifying powers1 occupies an intermediate position between spirit and balsam1 being much more refractive than the former1 infinitely less so than the latter4 ,it is1 therefore1 of very great value for the preservation of such tissues as possess a medium degree of transparency1 and which would become obscured if mounted in spirit1 or have their outlines rendered indistinct if preserved in balsam4 ,it is of the utmost value for mounting unstained anatomical sections which1 when put up in this medium1 reveal such minute details of structure as would readily have escaped observation had any other agent been employed4 ,it may also be used with stained sections1 but in this case the sections should be of extreme thinness1 otherwise the refractive power of the glycerine will be insufficient to render them thoroughly transparent4 ,the great drawback to the use of glycerine is the extreme difficulty experienced in preventing its escape from beneath the covering glass1 for it unfortunately possesses such great penetrating power that no cement hitherto devised can be thoroughly depended upon for withstanding its solvent action for any considerable length of time4#i ,attention to the instructions presently to be given 7 #af7 will1 however1 reduce this risk of leakage to a minimum4 ,in the use of glycerine ,dr4 ,carpenter's caution must ever be borne in mind1 viz41 that1 as carbonate of lime is in time dissolved by glycerine1 this agent ought never to be employed for the preservation of objects containing such salt4 ,footnote #i3 ,note ,h4 #af4 ,mounting in ,glycerine4--,to illustrate the method of using this medium we will mount our present sections in glycerine4 ,in the first place we shall require a deep watch-glass1 which is to be half filled with glycerine diluted with an equal amount of distilled water4 ,by means of the spoon1 one or more sections may be transferred into this1 either directly from the acetic acid solution 7 #ad71 or if1 since cutting1 they have been preserved in spirit1 they should first undergo a short immersion in a large vessel full of water4 ,the watch-glass should now be covered with an inverted wine-glass1 and put away for some hours1 in order that the sections may become thoroughly saturated with the dilute glycerine4 ,when this has been accomplished1 a slide must be cleaned1 and one of the sections1 with the aid of the unpierced end of the spoon1 be transferred to its centre4#aj ,as the kind of section with which we are now dealing is1 or ought to be1 of extreme thinness1 no cell 7 #bf7 is necessary4 ,after tilting up one end of the slide1 so as to drain off as much of the weak glycerine as possible1 a drop of ,price's best glycerine must1 with a glass rod or pipette1 be allowed to fall gently upon the section1 so as to avoid the formation of air-bubbles4 ,if any of these1 however1 should be produced1 they must be removed with the point of a needle set in a wooden handle1#aa and the slide then covered with a small bell-glass 7or wine-glass74 ,a circular cover is now to be cleaned with a soft handkerchief1 and after gently blowing from it any adhering fibres of lint1 etc41 it will be advisable to hold the side of the glass which is to come into contact with the preparation close to the mouth1 and breathe upon it1 so as to cover it with moisture4 ,the cover held between the thumb and forefinger of the left hand must now be applied by its edge near to the margin of the preparation1 and the surface of the cover directed in an inclined manner over it4 ,beneath the overhanging edge of the cover the point of the needle1 held in the right hand1 is now to be inserted 7see ,figure74 ,by gently lowering the needle1 the cover will come into gradual contact with the slide1 driving before it a minute wave of glycerine1 in which any air-bubbles that may have become developed are usually carried off4 ,a very considerable degree of tact1 however1 is required to perform this little operation1 simple as it may appear1 for the retreating wave of glycerine not unfrequently floats out the section1 either wholly or partially1 from beneath the cover4 ,air-bubbles1 also 7the btes noires of this process71 are exceedingly likely to arise4 ,when this happens the best plan to adopt is1 by means of the needle point1 gently to raise and remove the cover1 apply another drop of glycerine to the section1 and cover with a fresh piece of thin glass4 ,it will now be necessary to remove any superfluous glycerine which may have collected around and near the cover4 ,the great bulk must be wiped away by means of a camel's-hair pencil1 slightly wetted between the lips1 any remaining stickiness being removed with a bit of blotting paper which has been slightly damped4 ,with a very small camel's-hair pencil1 charged with solution of gelatine1 a ring must be made round the margin of the cover1 of sufficient breadth to take in a small tract of both cover and slide4 ,as this cement is perfectly miscible with glycerine1 it readily unites with any of that fluid which may ooze from beneath the cover1 and which1 in the case of any of the ordinary varnishes1 would act as a fatal obstacle to perfect adhesion4 ,to make the cement1 take half an ounce of ,nelson's opaque gelatine1 put in a small beaker1 add sufficient cold water to cover it1 and allow the mixture to remain until the gelatine has become thoroughly soaked4 ,the water is now poured off1 and heat applied until the gelatine becomes fluid1 when three drops of creosote should be well stirred in1 and the fluid mixture transferred to a small bottle to solidify4 ,before use1 this compound must be rendered liquid by immersing the bottle containing it in a cup of warm water4 ,when the ring of gelatine has become quite set and dry 7which will not take long71 every trace of glycerine must be carefully removed from the cover and its neighborhood1 by gently swabbing these parts with a large camel's-hair pencil dipped in methylated spirit4 ,after drying the slide a ring of ,bell's microscopical cement may be applied over the gelatine1 and1 when this is dry1 another coat is to be laid on4 ,if it be desired to give the slide a neat and tasteful appearance1 it is a very easy matter1 by means of the turn-table1 to lay on a final ring of ,brunswick black or white zinc cement 7 #bd74 ,every care has now been taken to render our preparation permanent2 but1 to make assurance doubly sure1 it will be well to follow ,dr4 ,carpenter's advice1 and1 every year or so1 to lay on a thin coating of good gold-size4#ab ,footnote #aj3 ,the appearance of a slide is vastly improved if the preparation be placed exactly in its centre4 ,this may readily be done in the following manner3--,take some very finely-powdered ,prussian blue1 and rub it up in a mortar with a little of the weak gum solution 7 #aa71 so as to form a thin blue pigment4 ,a quantity of this should be made1 so as always to be at hand4 ,a slide having been cleaned1 the best surface is to be selected1 and on the reverse side1 by means of the self-centring turn-table1 a small circle is to be drawn with a camel's-hair pencil1 charged with the pigment4 ,in the centre of this ring1 but on the opposite side of the slide1 the section is to be placed1 when it of course will occupy a position exactly central4 ,when the slide comes to be finished1 the blue ring may easily be removed with a wet rag4 ,footnote #aa3 ,a crochet-needle holder made of bone1 and which may be bought at the smallware dealers' for about sixpence1 makes an admirable handle for microscopical needles4 ,at one extremity there is a small cavity1 closed with a cap1 for the storage of reserve needles1 whilst the other end terminates in a metal tip1 provided with a crucial slit and central perforation for the reception of the needle in actual use1 and so arranged that1 by means of a small screw-nut1 needles of various sizes may be firmly held in position4 ,footnote #ab3 ,if square covers be employed1 they may be fixed to the slide by a simple method much in vogue in ,germany4 ,a thin wax taper is to be lighted1 and being partially inverted for a few seconds1 the wax surrounding the wick will become melted4 ,after the slide has been freed from excess of glycerine1 a drop of this heated wax is allowed to fall upon each corner of the cover1 and a line of the melted wax run along the margins of the cover between these points1 so as perfectly to surround it4 ,if a good coat of white zinc cement be subsequently laid over the wax a very durable1 and not unornamental1 line of union will have been formed4 ,illustration3 ,,method ,,of ,,applying ,,cover4 #ag4 ,use of ,freezing ,microtome4--,our preceding consideration of the method of employing the microtome in conjunction with paraffine as an imbedding agent 7 #aa71 will have formed a very suitable introduction to the study of the somewhat more complicated process of imbedding the tissue in gum1 for section in the freezing microtome4 ,this method is of the utmost value to the practical histologist1 for by its means he is enabled with ease to possess himself of perfect sections of several structures1 the cutting of which1 before the introduction of this process1 was always a matter of difficulty and anxiety4 ,the freezing microtome is especially valuable for the section of such substances as from their extreme delicacy are liable to be injured by being imbedded in paraffine--for instance1 the delicate villi of the intestines becomes very frequently1 by the use of paraffine1 denuded of their epithelium1 and the villi themselves not seldom become torn off or otherwise damaged4 ,the great value of the method is also very well seen in the treatment of those tissues which1 like the lung1 are of such loose and spongy texture as to offer insufficient resistance to the knife unless their interstices have previously been filled up with some solid yet easily cut material4 ,as the space at our command is strictly limited1 we are precluded from entering as fully into this branch of section-cutting as the importance of the subject demands and our own inclination would lead us4 ,to those who wish to become thoroughly conversant with the full value of this method we cannot do better than recommend the perusal of ,professor ,rutherford's ,practical ,histology1 #b;d edition1 than which1 on the whole subject of physiological microscopy1 no treatise with which we are acquainted is at once so plain1 practical1 and profound4 #ah4 ,employment of ,freezing ,microtome4--,a very suitable object with which to demonstrate the method of using this form of microtome will be afforded us by a portion of intestine1 say of the ileum of a cat or dog4 ,suppose we have some of this in methylated spirit--let us select a piece of about half an inch in length4 ,our first care will be to deprive this of its spirit2 for so long as the tissue remains impregnated with alcohol it would1 of course1 be impossible to freeze it4 ,we will1 therefore1 throw it into a large basinful of water1 and leave it there for twenty-four hours1 during which time it would be as well to change the water once or twice4 ,we shall now require a strong solution of gum4 ,this1 which should have been made some time previously1 may be prepared by placing a quantity1 say three or four ounces1 of ordinary gum arabic in a glass beaker1 and adding sufficient water to cover it--the mixture must be stirred occasionally with a glass rod until solution has taken place1 which will be in a few days4 ,if necessary a little more water may be added1 but so long as the gum will pour from vessel to vessel1 it cannot well be made too strong4 ,mucilage1 by keeping1 is very apt to become sour and mouldy--this may be prevented by adding to each ounce of the water with which it is prepared about half a grain of salicylic acid4 ,we now pour some of this mucilage into a small vessel--an egg cup will answer very well--and into it transfer the piece of ileum from the water4 ,here we must allow it to remain for a time sufficient to permit of its becoming thoroughly saturated with the gum1 for which purpose some hours will be necessary4 ,when this soaking has been accomplished we will prepare the microtome1 which we will assume to be ,rutherford's4 ,in the first place it will be necessary to remove the plug--which is to be done by turning the handle connected with the screw until the plug rises so high in its tube that it may be grasped with the fingers and removed1 when it is to be well smeared all over with sperm oil and replaced4 ,this is done to prevent any unpleasant adhesions taking place whilst the freezing is going on4 ,we must next depress the plug1 so as to convert the upper part of the tube into a kind of 8well0 of sufficient depth to hold our specimen4 ,it will now be very advisable to look carefully into this well and observe whether the plug fits accurately into the tube 7 #h7 for if there be any interval between the two it will give rise to much subsequent annoyance1 as the gum penetrating this interstice will there become firmly frozen into irregular patches1 which will so interfere with the even gliding of the plug within its tube as to cause the former to ascend in such an irregular and jerky manner as to be utterly destructive of all accuracy in the cutting4 ,if this defect be observed1 it may be at once remedied by dropping a small quantity of gently heated paraffine into the well1 which will effectually close up any fissures4 ,the microtome1 by means of its clamping arrangement1 must now be firmly attached to the table1 and a suitable vessel be placed on the floor beneath it1 so that it may catch the water which will issue from the waste-pipe of the apparatus4 ,the next requirement is a supply of block ice and finely-powdered salt4 ,a lump of the ice must be wrapped in a towel1 and crushed into small pieces2 these1 by means of a large mortar1 are to be further reduced to a very fine powder4 ,any attempt to hurry over this troublesome part of the operation will lead to future disappointment1 for unless the ice be used in a very fine powder great delay 7at least7 in the freezing will be the result4 ,with the aid of a small spoon the ice and salt are in alternate spoonsful to be conveyed into the freezing-box of the machine1 great care being taken that the cavity under the cutting-plate and around the tube be thoroughly packed1 after which the uncovered portion of the box should also be well filled4 ,the well is now to be filled with the strong gum to within a little distance of its top1 and a piece of sheet gutta-percha 7such as shoe soles are made of7 being applied over the well1 and kept in position by a weight1 we must wait until the freezing commences4 ,in a short time we shall notice that the gum has acquired a thick muddy appearance4 ,the tissue must now1 by means of the forceps1 be transferred to the well1 and there placed in such a position that the sections1 when cut1 shall run in the desired direction4 ,after more gum has1 if necessary1 been added1 so as completely to cover the tissue1 the well is again to be covered1 and attention given to the freezing-box4 ,as the mixture which this contains becomes melted1 it must constantly be renewed1 care being at the same time taken that the mouth of the discharge-pipe be kept quite free1 otherwise water accumulating in the box1 the freezing mixture will degenerate into a useless puddle4 ,when the gum becomes sufficiently hard to cut1 this must be done much in the same manner as if paraffine had been used 7 #ab74 ,in this case1 however1 no fluid will be required1 or must be used1 to wet the knife with1 and especial care must be taken that in disengaging the sections from the knife into the water they be not torn4 ,these sections often adhere very tenaciously to the blade1 but if a little patience be exercised the water will soon float them off in safety--much more safely than if any attempt be made to liberate them prematurely4 ,there is one circumstance connected with the use of the freezing microtome which is rather annoying4 ,the moisture of the breath and atmosphere is apt to become condensed on the cutting-plate1 and here1 mixed with accidental smears of gum1 it becomes frozen into a jagged and irregular sheet of ice1 which not only seriously interferes with the smooth play of the knife1 but also constitutes a real peril to its edge4 ,as this evil cannot be avoided1 all we can do is1 by constant wiping1 to keep the cutting-plate clean and free from this accumulation4 ,this is best done with a bit of soft rag just moistened with spirit1 but this must not come into contact with any portion of the cylinder of frozen gum1 else it will instantly thaw it4 ,when using the freezing microtome it is always advisable to wear an apron1 otherwise our clothes may receive considerable damage from the constant splashing of the salt water1 as it falls from the waste-pipe into the vessel beneath it4 ,after use1 the microtome must be well washed in plenty of cold water till every trace of salt be removed1 for if any of this remain it will quickly corrode the brass-work of the instrument4 ,the plug and screw1 as also the section-knife1 should be well smeared with ,rangoon oil before the machine is put away4 #ai4 ,logwood ,staining4--,the employment of logwood as a staining agent is now becoming very general4 ,it acts much in the same manner as carmine1 but the violet color which it produces is by many thought to be of a more soft and agreeable character than that due to the action of carmine4 ,a valuable and very convenient property also which it possesses is that it stains tissues very rapidly1 and this without interfering with that differential kind of coloration 7 #ad7 upon which the chief value of all staining processes depends4 ,a simple method of preparing the logwood fluid is to mix an aqueous solution of extract of logwood with a solution of alum 7#a to #h7 till the deep impure red colour has become violet1 and then to filter the mixture 7,frey74 ,this will stain sections in about half an hour4 ,this stain1 though here mentioned for the ease with which it may be made is1 as a rule1 very inferior to a fluid prepared directly from hmatoxylon1 the alkaloid or active principle of logwood4 ,as1 however1 it is difficult and troublesome to make the solution in this manner1#ac it will be advisable for the student to purchase1 ready prepared1 such small quantity of the dye as he may require4 ,small bottles may be obtained for a few pence of ,mr4 ,martindale1 #aj1 ,new ,cavendish ,street1 ,london1 and from repeated trials of this solution we can recommend it as producing excellent results4 ,it is a very strong fluid1 and requires to be diluted before use4 ,the degree to which the dilution must be carried cannot1 however1 be very accurately indicated1 for all staining fluids of this nature possess the very undesirable property of becoming decomposed by age4 ,after the fluid has been kept for some time1 a portion of the colouring matter is thrown out of solution1 and becomes deposited upon the sides and bottom of the vessel in which it is contained1 hence the older the preparation1 the weaker it will have become4 ,as the time required for staining with logwood is but short1 it is desirable that all the sections should begin to be submitted to its action at the same time1 otherwise some will become more deeply stained than others4 ,a good plan is to fill a small porcelain jar 7 #ad7 with filtered water1 and into this transfer the sections4 ,whilst they are settling well down to the bottom1 a mixture must be prepared of half a drachm of ,martindale's solution 7fresh7 to one ounce of distilled water1 and everything got in readiness for its immediate filtration4 ,the water is now very gently to be poured off the sections1 and if care be exercised this may be done in such a manner as to leave them undisturbed at the bottom1 after removing almost every drop of water4 ,the diluted logwood fluid must now be immediately filtered upon the sections1 so that they may run no risk of becoming dry4 ,in the present instance the staining may be allowed to proceed for about thirty minutes1 and this will be found a convenient time for the immersion of the general run of animal sections4 ,if the logwood fluid be not quite fresh1 either a little more of it will have to be added to the water1 or the time of immersion must be prolonged until the desired depth of color has been produced4 ,it is well whilst the staining is going on gently to shake the vessel occasionally1 so that the sections may not remain in a heap at the bottom1 but all be as fully as possible exposed to the action of the dye4 ,when the staining is judged to be complete1 the logwood solution must be gently poured off1 leaving the stained sections at the bottom of the jar1 when they should be quickly covered with methylated spirit1 which will fix the colour4 ,we shall now be able to see if the coloration obtained be perfectly satisfactory4 ,if not deep enough1 it is very easy again to submit them to the action of the dye for a few minutes longer4 ,if on the other hand1 and as more frequently happens1 the coloration should be too deep1 the excess of colour may readily be removed by transferring the sections for a short time into some diluted acetic acid prepared by adding five drops of the glacial acid to an ounce of water4 ,the action of this should be carefully watched1 and when the colour has been reduced to the desired tint the sections may be retransferred to the methylated spirit4 ,footnote #ac3 ,should the student1 however1 determine to prepare this solution for himself1 he will find a good formula for the purpose in ,schfer's 8,practical ,histology10 p #agf4 ,note ,i4 #bj4 ,absolute ,alcohol4--,as we purpose mounting the sections which have just been stained1 in ,canada balsam1 we will briefly consider the preliminary treatment to which they must be submitted before this can be effected4 ,the object of this is to abstract from the tissue all its water1 for if any moisture be permitted to remain in the section it will1 when mounted in balsam1 become obscured and surrounded by a kind of opalescent halo1 due to the imperfect penetration of the balsam into the only partially dehydrated tissue4 ,the old-fashioned plan of dehydration was simple exposure to the air4 ,the method now generally adopted is to bring about the same result by means of absolute alcohol4 ,this fluid has such a strong affinity for water that tissues submitted to its influence are rapidly and effectually deprived of any water they may contain4 ,absolute alcohol in small quantity may be obtained from the druggist at about sixpence per ounce4 ,it will be necessary for the student to provide himself with a little of this agent1 say about two ounces1 the method of using which will very shortly be explained4 ,absolute alcohol must be kept in a bottle with a very accurately-fitting stopper1 in order to prevent its absorbing moisture from the air4 ,for our purpose such a bottle1 having a neck as wide as possible1 is to be selected4 #ba4 ,clove ,oil4--,after being thoroughly dehydrated the sections may1 in special instances 7 #dh71 be at once mounted in balsam2 but1 as a general rule1 it will be found necessary 7particularly in the case of animal sections7 to treat them with some clarifying agent1 in order to remove the cloudiness and opacity which is 7in part7 due to their previous immersion in alcohol4 ,for this purpose turpentine1 or any of the essential oils1 may be used3 of these1 oil of cloves is to be specially recommended4 ,it is rather expensive1 ranging from sixpence to one shilling per ounce3 but1 as a drop or two will be sufficient for preparing each slide1 only a small quantity--say half an ounce or an ounce--need be procured4 ,the most convenient vessel in which to keep the oil is one of the small test bottles used by watchmakers4 ,these bottles are provided with a glass cap to exclude dust1 and the stopper is prolonged into a glass rod1 which dips into the bottle4 ,the use of this rod and the method of employing the oil will be explained shortly4 #bb4 ,canada ,balsam1 as ordinarily met with1 is a thick resinous balm of great viscidity1 but readily rendered perfectly fluid by the application of heat4 ,formerly1 sections were mounted in this medium in its pure state1 but owing to the annoyance which was so constantly being experienced from the tenacity with which intruding air-bubbles were held by the viscous medium1 this plan of mounting is rapidly falling out of use4#ad ,it is now usual to employ the balsam in a diluted condition1 the two chief diluents being chloroform and benzole4 ,as balsam1 however1 often contains more or less moisture1 it is desirable to drive this off before adding the diluent4 ,a very convenient way of doing so is to expose some pure balsam to the heat of a cool oven for several hours1 when the balsam will be found to have assumed a hard1 vitreous character4 ,it should now be broken into small pieces1 these put into a bottle1 and some methylated chloroform added1 which in a little while will completely dissolve the hardened balsam4 ,more chloroform is then to be added1 until a solution is obtained sufficiently thin to run through filtering-paper4 ,a glass spirit lamp must now be procured1 having a capacity of about two ounces1 and provided with a cap4 ,into the wick-holder of this 7which must be made of porcelain7 a hollow glass tube is to be so fitted that its end dips into the lamp to within about a third of the bottom4 7,see ,fig47 ,the thin chloroform-balsam is now to be filtered into this lamp1 very fine filtering-paper--through which a little chloroform has first been passed--being used for the purpose4 ,when the lamp is full it must 7deprived of its cap7 be put in a warm place until sufficient of the chloroform has evaporated to leave behind it a fluid of the consistence of thin syrup4 ,footnote #ad3 ,although we cannot too strongly insist upon the use of chloroform-balsam wherever practicable1 yet it sometimes happens in the mounting of substances of considerable thickness1 that after all the chloroform has evaporated an insufficient amount of balsam is left behind to fill up the cavity between slide and cover4 ,in such cases1 therefore1 it is advisable to use pure balsam1 which may be done in the following manner4 ,the object having been previously thoroughly dehydrated by immersion in absolute alcohol1 is to be thence transferred to a little good turpentine1 or benzole1 where it should remain until perfectly transparent4 ,it is now to be placed in the centre of a slide which has been gently warmed1 and a drop or two of fresh fluid balsam added1 the greatest care being taken to prevent the formation of air-bubbles4 ,should such arise they must be touched with the point of a heated needle1 which will cause them to burst and disappear4 ,the chief difficulty of the process has yet to be encountered in the application of the cover2 for it is during this procedure that the development of air-bubbles is most likely to take place4 ,this annoyance may1 however1 be entirely avoided by taking the simple precaution of dipping the cover into turpentine before it is applied 7 #af71 when it will be found that 8you can't get air-bubbles1 even if you try40 ,the courtesy of ,mr4 ,j4 ,a4 ,kay1 of ,chatham1 enables us to give our readers the benefit of this practical 8wrinkle40 ,illustration3 ,,spirit ,,lamp ,,adapted ,,to ,,contain ,,balsam4 #bc4 ,mounting in ,balsam4--,let us now return to our sections which1 it will be remembered1 were left in methylated spirit 7 #ai74 ,these we will now mount in balsam1 and although1 of course1 any number may be proceeded with at the same time1 yet to avoid confusion1 in the following directions one section only will be spoken of4 ,this section then is1 with the perforated spoon1 to be transferred to the bottle of absolute alcohol1 where it may remain for about an hour--considerably less time is actually required1 but as from constant use the spirit becomes weakened1 it is as well to be on the safe side4 ,it must now be removed to the centre of a clean glass slip1 and here the plain end of the spoon comes into use4 ,if this be employed for effecting the transfer1 it will be found that when the section is being removed from the alcohol it will bring along with it a small pool of the spirit4 ,a slight touch of the needle applied to the edge of the section will cause it to float from the spoon on to the slide1 at the same time carrying the pool of alcohol with it1 in which it will gently spread itself out upon the slide without the faintest risk of injury4 ,the superfluous spirit is now to be drained off1 and just as the section is becoming glazed and sodden-looking 7not dry7 we must1 by means of the long glass stopper 7 #ba71 apply to it a large drop of clove oil4 ,the oil1 however1 should not be placed on the section1 but be allowed to drop on to the slide near to its margin4 ,by gently tilting the slide the oil will gradually insinuate itself beneath the section and slowly ascend through it to the surface4 ,the slide should now be covered with a bell-glass 7or wine-glass71 and about two minutes allowed for the oil thoroughly to saturate the section4 ,as much as possible of the superfluous oil must then be drained off1 and the remainder removed with blotting paper4 ,by means of the glass rod a small quantity of chloroform-balsam is now taken from the spirit lamp which contains it1 and allowed gently to fall upon the section1 which must then be covered with a thin glass circle in the manner previously described 7 #af74 ,when the object is very fragile1 it is a good plan1 after draining off the clove oil1 to apply the cover directly upon the section1 and then to place a drop of the balsam near to the edge of the cover4 ,this1 by capillary attraction1 will speedily diffuse itself beneath the cover1 flowing over and surrounding the object1 without in the slightest degree disturbing its position4 ,if1 during the process of mounting1 any air-bubbles arise1 we may view their development with equanimity1 being well assured that as the chloroform evaporates they too will quickly disappear4 ,when the mounting is completed1 the slide should be roughly labelled and placed on a warm mantel-piece for a few days to dry4 #bd4 ,finishing the ,slide4--,in the course of two or three days it will be advisable to take an old penknife1 and after heating the blade in the flame of a spirit lamp1 gently to run the point of it round the margin of the cover1 so as to remove any excess of balsam which may have oozed from beneath it4 ,in a few days more1 any remaining balsam may be carefully scraped away with a cold knife4 ,all remaining traces of balsam are then to be removed from around the cover by means of a rag just moistened with methylated spirit1 or1 what is better1 with a mixture of equal parts of spirit and ther1 after which the slide is to be thoroughly washed in cold water4 ,the slide is now in reality finished1 but1 in order to give it a smart appearance1 it is usual1 with the assistance of the turn-table1 to run a ring of colored varnish round the covering glass4 ,a very useful varnish for the purpose is the white zinc cement4 ,to prepare this1 dissolve an ounce of gum dammar in an ounce of turpentine by the aid of heat4 ,take one dram of oxide of zinc and an equal quantity of turpentine2 rub them up together in a mortar1 adding the turpentine drop by drop1 so as to form a creamy mixture perfectly free from lumps or grit4 ,one fluid ounce of the dammar solution previously made must now gradually be added1 the mixture being kept constantly stirred 7,frey74 ,the cement1 when made1 should be strained through a piece of fine muslin1 previously wetted with turpentine1 into a small wide-necked bottle1 which1 instead of having a cork or stopper1 should be covered with a loose metal cap4 ,instead of a bottle1 the varnish may be kept in one of the collapsible tubes used by artists2 but though this plan is highly recommended by many1 it is not without its disadvantages4 ,if the varnish becomes thick by keeping1 a few drops of turpentine or benzole well stirred in will soon reduce it to a suitable consistence for use4 ---------------------------------------- -------------------------------- ,,part ,,ii4 #be4 ,special ,methods4--,having in the preceding pages entered at some length into the general subject of section-cutting1 it remains for us now to consider those special methods of preparation which the peculiarities of certain objects demand4 ,in order to keep the bulk 7and consequent price7 of this manualette within due bounds1 we shall1 without further preface1 proceed to the description of these methods1 in doing which every endeavour will be made to employ such brevity of expression as may be consistent with perfect clearness of meaning4 ,as the most convenient plan1 the objects here treated of will be arranged in alphabetical succession4 #bf4 ,bone4--,both transverse and longitudinal sections should be prepared1 the former being the prettier and most interesting4 ,after prolonged maceration in water1 all fat1 etc41 must be removed and the bone dried1 when as thin a slice as possible is to be cut off in the desired direction1 by means of a very fine saw4 ,if the section so obtained be placed upon a piece of smooth cork it may1 with the aid of a fine file and the exercise of care1 be further reduced in thickness4 ,it is then to be laid upon a hone moistened with water1 and being pressed gently and evenly down upon it with the tip of the finger 7protected1 if necessary1 by a bit of cork or gutta-percha71 it must be rubbed upon the stone until the desired degree of thinness has been attained4 ,finally1 in order to remove scratches and to polish the section1 it should be rubbed upon a dry hone of very fine texture1 or upon a strop charged with putty-powder4 ,after careful washing in several waters the section must be allowed thoroughly to dry1 when it may be mounted by the dry method in the following manner3--,a ring of gold-size must1 by means of the turn-table1 be drawn in the centre of a slide1 and the slide put away in a warm place for several days 7the longer the better71 in order that the ring may become perfectly dry and hard4 ,when this has been accomplished the section is to be placed in the centre of the ring1 and a covering circle of the requisite size having been cleaned1 this must have a thin ring of gold-size applied round its margin4 ,the cover is now to be placed in position and gently pressed down1 a spring clip being employed1 if necessary1 to prevent it from moving4 ,in about twenty-four hours another layer of the varnish should be applied1 and the slide afterwards finished in the manner already described 7 #bd74 ,the above method is also applicable to the preparation of sections of teeth and also of fruit-stones and other hard bodies1 which are incapable of being rendered soft enough for cutting4 ,as the process just described1 however1 is both troublesome and tedious1 it is much better for ordinary purposes to have recourse to the decalcifying method1 by which means sections in every way suitable for the examination of the essential structure of bone may be obtained with ease4 ,to carry out this plan a piece of fresh bone should be cut into small pieces and placed in a solution made by dissolving #ae grains of pure chromic acid in #g ounces of distilled water1 to which #cj minims of nitric acid s4 g4 #a4dbj are afterwards to be added4 ,here they should remain for three or four weeks1 or until the bone has become sufficiently soft to cut easily1 the fluid being repeatedly changed during the process4 ,from this solution they must be transferred to methylated spirit for a few days1 when a piece may be selected1 imbedded in paraffine1 and cut in the microtome 7 #ab74 ,some of the sections should be mounted1 unstained1 in spirit4 ,for this purpose a cell of gold-size1 as above described1 must first be prepared and filled full of a mixture of spirit of wine one part1 and distilled water three parts4 ,into this the section must be carefully placed and the cover applied1 the same precautions for the exclusion of air-bubbles being taken which were recommended when speaking of mounting in glycerine 7 #af74 ,when the cover is in position a ring of gold-size must be laid on1 repeated when dry1 and the slide afterwards finished in the ordinary manner4 ,it will also be advisable to stain some of the sections with carmine 7 #ad71 or picro-carmine 7 #db71 and mount them in glycerine4 ,teeth may also be treated by the decalcifying method1 but in this case it must be remembered that the enamel will dissolve away4 #bg4 ,brain4--,the best hardening fluid is that recommended by ,rutherford1 and is made by dissolving #ae grains of pure chromic acid and #ca grains of crystalized bichromate of potash in #dc ounces of distilled water4 ,small pieces of brain1 which have previously been immersed for twenty-four hours in rectified spirit1 should be placed in about a pint of this solution1 where they must remain for five or six weeks1 the fluid being repeatedly changed during the process4 ,if by this time they are not sufficiently hard the induration must be completed in alcohol4 ,sections are easily cut in the microtome by the paraffine method 7 #ab74 ,these may advantageously be stained in a solution of aniline blue1 made by dissolving #a-a_/b grain of aniline blue in #aj ounces of distilled water1 and adding #a drachm of rectified spirit 7,frey74 ,as this stain acts very rapidly two or three minutes' immersion will generally be found long enough4 ,the sections must then be mounted in balsam 7 #bc74 #bh4 ,cartilage4--,the method to be employed in the preparation of cartilage will entirely depend upon the nature of the staining agent1 to the action of which the sections are to be submitted4 ,thus1 if the elegant gold method is to be followed1 it is necessary that the cartilage should be perfectly fresh2 whilst if any of the other staining agents are to be employed the tissue may have been previously preserved in alcohol4 ,an excellent object on which to demonstrate the gold process is to be found in the articular cartilage of bone4 ,it is a very easy matter to obtain from the butchers the foot of a sheep which has just been killed4 ,the joint is to be opened1 and the bones dissociated1 when they will be seen to have their extremities coated with a white glistening membrane--this is the articular cartilage4 ,exceedingly thin slices must be at once cut from it1 and as only small sections are required1 a sharp razor may be used for the purpose1 the blade being either dry or simply wetted with distilled water4 ,the sections as cut are to be transferred to a small quantity of a half per cent4 solution of chloride of gold in a watch glass4 ,chloride of gold may be purchased in small glass tubes hermetically sealed1 each tube containing #ae grains1 and costing about #bs4 ,if1 however1 the student requires only a small quantity of the staining fluid he need not be even at this small expense1 for as photographers for the requirements of their art always keep on hand a standard solution of chloride of gold of the strength of one per cent41 a little of this may readily be obtained1 and diluted to the required degree4 ,after the sections have been exposed to the action of the staining fluid for about ten minutes they may be transferred to a small beaker of distilled water1 and exposed to diffused light for about twenty-four hours1 when they must be mounted in glycerine 7 #af74 ,sections of cartilage may also be examined1 without being stained1 in which case the field of the microscope should be only very feebly illuminated4 ,or carmine staining 7 #ad7 may be resorted to--these sections show well in glycerine1 or if the staining be made very deep1 even ,canada balsam may be employed1 and with fair results4 ,microscopists are indebted to ,dr4 ,frances ,elizabeth ,hoggan for the description of a new method of staining1 which we have found especially suited to the treatment of cartilage4 ,the agent employed is iron1 and the process1 which is very simple1 is as follows4 ,two fluids are necessary--7#a7 tincture of steel2 7#b7 a two per cent4 solution of pyrogallic acid in alcohol4 ,a little of the former is to be poured into a watch glass1 and into this the sections1 after having been previously steeped in alcohol for a few minutes1 are to be placed4 ,in about two minutes the iron solution is to be poured away and replaced by solution ,no4 #b4 ,in the course of a minute or two the desired depth of colour will have been produced1 when the sections are to be removed1 washed in distilled water1 and mounted in glycerine4 ,the results obtained by this process are very beautiful1 the colour produced being a very fine neutral tint1 of delightful softness4 ,the process also answers admirably in the case of morbid tissues1 and we have now in our possession some sections of ulcerated cartilage tinged by the iron method1 in which the minute changes resulting from the ulcerative disintegration are brought out with wonderful distinctness4 ,as the structure of cartilage differs according to its purpose and situation1 the student will find his time profitably employed in a careful examination of the following forms 77 hyaline--articular and costal2 77 yellow fibro-cartilage--epiglottis1 or external ear2 77 cellular--ear of mouse4 ,sections of the intervertebral ligaments should also be made1 in which the different kinds of cartilage may be examined side by side with each other4 #bi4 ,coffee ,berry affords sections of great beauty4 ,the unroasted berry should be soaked for hours or days in cold water until sufficiently soft2 then imbedded in paraffine1 and cut in the microtome 7 #ab71 the section being made in the direction of the long axis of the berry4 ,put up in glycerine1 or stain rather strongly with carmine1 and mount in balsam4 ,the same method of treatment may also be applied to other hard berries or seeds4 #cj4 ,fat4--,adipose tissue may be hardened in alcohol1 cut in paraffine1 and mounted in glycerine4 ,if the tissue has been injected the sections may be mounted in balsam1 and are then very beautiful objects1 showing the capillary network encircling the fat cells4 #ca4 ,hair4--,longitudinal sections are readily made by splitting the hair with a sharp razor4 ,it is more difficult to cut the hair transversely4 ,this1 however1 may easily be done in the following manner4 ,the hairs having previously been well soaked in ther to remove all fatty matters1 a sufficient number of them must be selected to form a bundle about the thickness of a crow quill4 ,this bundle1 after being tied at each extremity with a bit of thread1 is to be immersed for several hours in strong gum 7 #ah17 to which a few drops of glycerine have been added4 ,on removal1 the bundle must be suspended by means of a thread attached to one end of it1 in a warm place until sufficiently hard1 when it is to be imbedded and cut in paraffine 7 #ab74 ,each section1 as cut1 is to be floated off the knife into methylated spirit4 ,from this it is with the aid of the spoon 7 #ad7 to be transferred to a slide1 the spirit tilted off1 a drop of absolute alcohol added1 when1 after a minute or two1 this also is to be drained off1 the section treated with clove oil1 and the mounting completed as described in #bc4 #cb4 ,horn varies very much in consistence1 in some instances having a cartilaginous character1 whilst in others it is almost bony4 ,in the latter case1 sections will have to be ground down in the manner explained when speaking of bone 7 #bf74 ,where the texture is less dense1 recourse may be had to prolonged steeping in hot or boiling water2 in some cases it will be necessary to continue the immersion for several hours4 ,when sufficiently soft the piece of horn may1 by means of bits of soft wood1 be firmly wedged into the tube of the microtome1 and sections cut with a razor1 or what is better1 with a broad and very sharp chisel4 ,the sections are to be put between glass slips1 held together by ,american clips 7or pegs71 and put away for two or three days in order to become thoroughly dry4 ,after well soaking in good turpentine or benzole1 they must be transferred to slides1 the superfluous turpentine drained off1 and chloroform-balsam added1 etc4 7 #bc74 ,sections of horn should1 of course1 be cut in different directions1 but for examination with the polariscope those cut transversely yield by far the most magnificent results4 ,hoofs1 whalebone1 and allied structures should also be treated by the above method4 #cc4 ,intestine4--,the method to be pursued with sections has already been described 7 #ah74 ,the ileum1 however1 is a very pretty object when a portion of it is so mounted as to show the villi erect4 ,to do this it is necessary to cement to the slide1 by marine glue1 a glass cell of sufficient depth4 ,this should have been prepared some time beforehand1 so that the cement may be perfectly dry and hard4 ,the cell is now to be filled with turpentine1 and the piece of ileum 7having been previously passed through methylated spirit and absolute alcohol into turpentine7 is gently placed into it1 having the villi uppermost2 pour some pure and rather fluid balsam on the object at one end1 and gradually incline the slide1 so as to allow the turpentine to flow out at the opposite side of the cell1 till it is full of balsam4 ,then take a clean cover1 and having placed upon it a small streak of balsam from one end to the other1 allow it gradually to fall upon the cell1 so as to avoid the formation of air-bubbles 7 #ag71 and finish the slide in the usual manner4#ae ,or1 the intestine may be dried1 and mounted dry1 in a cell with a blackened bottom1 for examination as an opaque object4 ,footnote #ae3 ,ralf4 #cd4 ,liver4--,small pieces of liver may be very successfully hardened by immersion in alcohol1 beginning with weak spirit and ending with absolute alcohol4 ,cut and mount as usual4 #ce4 ,lung must be prepared in chromic acid 7 #e74 ,for the cutting of sections the freezing microtome 7 #ah7 is of especial value1 and should1 therefore1 be used4 ,if1 however1 the student be not provided with this instrument1 he must proceed as follows4 ,a small piece of lung1 previously deprived of all spirit1 is to be immersed until thoroughly saturated in solution of gum 7 #ah74 ,a small mould of bibulous paper 7 #b71 only just large enough to receive the piece of tissue1 having been prepared and filled with the mucilage1 the specimen is to be transferred to it4 ,the mould1 with its contents1 is now to be placed in a saucer1 into which a mixture of about #f parts of methylated spirit and #a part of water 7,schfer7 is to be poured until the fluid reaches to within about a third of the top of the paper mould4 ,in the course of several hours the surface of the mucilage will begin to whiten and solidify4 ,as soon as this occurs more dilute spirit must be poured into the saucer1 until the mould is completely submerged4 ,in a day or two the gum will be found to have acquired a suitable consistence for cutting1 when it must be removed from the spirit1 the paper mould peeled off1 and the mass imbedded and cut in paraffine1 the sections being afterwards treated as if they had been obtained by the freezing method 7 #ah74 ,if the solidification of the gum should proceed too slowly1 a few drops of pure spirit may be added to the contents of the saucer4 ,if1 on the other hand1 the gum should become overhard1 it will be necessary to put into the saucer a few drops of water1 and repeat this until the required consistence be obtained4 #cf4 ,muscle4--,harden in chromic acid1 and cut in paraffine4 ,transverse sections may be made to show the shape of the fibrils4 ,longitudinal sections will only be required in the case of injected tissues1 when such sections will be found very elegant1 showing1 as they do1 the elongated meshes of capillaries running between and around the muscular fasciculi4 ,mount in glycerine or balsam4 ,to see the transverse stri characteristic of voluntary muscle1 a very good plan is to take a bit of pork 7cooked or fresh71 and by means of needles to teaze it out into the finest possible shreds4 ,if these be examined in water or glycerine1 the markings will be shown very perfectly4 #cg4 ,orange-peel1 common object though it be1 is not to be despised by the microscopist4 ,transverse sections must be prepared by the gum method 7 #ce74 ,these sections are not to be subjected to the action of alcohol 7as this would destroy the colour71 but after drying between glass slides they must be soaked in turpentine and mounted in balsam4 ,we shall then have a good view of the large globular glands whose office it is to secrete that essential oil upon which the odor of the orange depends4 #ch4 ,ovary may be prepared in the same manner as liver 7 #cd74 ,sections1 which are to be cut in paraffine1 may be stained with carmine1 and mounted in glycerine or balsam4 ,apart from all scientific value1 we know of no slide for the microscope which1 even as a mere object of show1 surpasses in beauty a well-prepared section of injected ovary1 showing the wondrous ,graafian vesicles1 surrounded by their meandering capillaries4 #ci4 ,porcupine ,quill4--,soften in hot water1 cut in paraffine1 and mount in balsam4 ,much 7in our opinion too much7 lauded as an object for the polariscope4 #dj4 ,potato4--,from the large amount of water which it contains thin sections cannot be cut from the potato in its natural state4 ,it must1 therefore1 be partially desiccated1 either by immersion in methylated spirit for a few days or by exposure to the air4 ,sections may then readily be obtained by imbedding and cutting in paraffine4 ,such sections mounted in balsam are very beautiful1 the starch being seen in sit1 whilst if polarized light be employed each granule gives out its characteristic black cross4 #da4 ,rush is to be prepared and cut as orange-peel 7 #cg74 ,transverse sections of this 8weed0 furnish slides of the most exquisite beauty4 #db4 ,skin4--,to prepare skin for section a piece is to be selected which1 after having been boiled for a few seconds in vinegar1 must be stretched out on a bit of flat wood1 and being maintained in position by pins be allowed to remain until thoroughly dry4 ,then imbed in paraffine1 and cut exceedingly thin transverse sections4 ,these may be stained in carmine1 but more beautiful results are obtained if picro-carmine be employed4 ,sections of skin1 when stained by this agent are much increased both in beauty and instructiveness2 for the several constituents of the tissue becoming tinged with different colours are readily distinguishable from each other1 whilst the contrast of colouring forms a pleasing picture to the eye4 ,the method of preparing picro-carmine is very simple1 though it sometimes yields a solution not altogether satisfactory4 ,the best formula with which we are acquainted is that given by ,rutherford1#af and if due care be taken in following it out failure will generally be avoided4 8,take #ajj c4c4 of a saturated solution of picric acid4 ,prepare an ammoniacal solution of carmine1 by dissolving #a gramme in a few c4c4 water1 with the aid of excess of ammonia and heat4 ,boil the picric acid solution on a sand bath1 and when boiling add the carmine solution4 ,evaporate the mixture to dryness4 ,dissolve the residue in #ajj c4c4 water1 and filter4 ,a clear solution ought to be obtained2 if not1 add some more ammonia1 evaporate1 and dissolve as before40 ,sections may be exposed to the action of this fluid for a period varying from fifteen to thirty minutes1 then rapidly washed in water1 and mounted in glycerine4 ,they may also be mounted in balsam1 care being taken in that case to shorten as much as possible the period of their immersion in alcohol1 so that no risk may be run of the picric acid stain being dissolved out4 ,footnote #af3 8,practical ,histology10 #b;d edit4 p4 #agc4 ,if it is intended to study the structure of the skin with anything like thoroughness1 portions must of course be examined from different localities1 in order that its several varieties and peculiarities may be observed4 ,thus the sudoriforous1 or sweat glands1 may be found in the sole of the foot1 whilst the sebaceous glands are to be sought in the skin of the nose4 ,the papill are well represented at the tips of the fingers1#ag whilst the structure of the shaft of the hair1 together with that of the follicle within which its root is enclosed1 as also the muscles by which it is moved1 are to be studied in sections of skin from the scalp or other suitable locality4 ,footnote #ag3 ,it is well1 in connection with these papill1 to bear in mind a fact pointed out by ,frey1 namely1 that the tips of the fingers frequently become1 post-mortem1 the seat of extensive natural injections2 hence1 in sections from this region1 we frequently obtain good views of distended capillaries without having been at the trouble of previously injecting them4--,frey1 8,microscopical ,technology40 #dc4 ,spinal ,cord4--,the spinal cord1 say of a cat or a dog 7or if procurable1 of man71 after being cut into pieces about half an inch in length1 may be hardened in the usual chromic acid fluid 7 #e74 ,as it is peculiarly liable to overharden and become uselessly brittle1 the process must be carefully watched4 ,its further treatment is the same as that of brain4 ,these sections may be stained very satisfactorily by the ink process1 for communicating details of which we are indebted to the kindness of ,dr4 ,paul1 of ,liverpool4 ,the agent usually employed is ,stephenson's blue-black ink1 which1 for this purpose1 must be quite fresh4 ,as in the case of carmine1 two methods of staining may be adopted--either rapid1 by using concentrated solutions1 or more prolonged1 according to degree of dilution4 ,for the reasons previously given 7 #ad71 slow methods of staining are always to be preferred1 as yielding the most beautiful results1 yet1 for the purposes of preliminary investigation1 it is often convenient to have recourse to the quick process4 ,to carry out the latter plan1 an ink solution of the strength #a in #e--aj parts of water is to be freshly prepared1 and the sections exposed to its action for a few minutes4 ,for gradual staining the dilution must be carried to #a in #cj--ej1 and the time of immersion prolonged to several hours1 the sections being occasionally examined during the staining1 so that they may be removed just as they have acquired the desired tint4 ,when a satisfactory coloration has been obtained1 the preparations should be mounted in dammar or balsam 7 #bc74 ,one advantage of this method of staining is1 that definition is almost as good by artificial light as by day4 #dd4 ,sponge may readily be cut after being tightly compressed between two bits of cork2 or its interstices may be filled up by immersion either in melted paraffine 7 #aa7 or in strong gum 7 #ah71 and then cut as usual4 #de4 ,stomach requires no special method of hardening 7chromic acid74 ,sections should always1 when practicable1 be cut in the freezing microtome4 ,in default of this1 proceed in the manner as directed for lung 7 #ce74 ,both vertical and horizontal sections will1 of course1 be required4 ,if the preparation has been injected1 the latter are particularly beautiful4 ,stain with carmine or aniline blue 7 #bg71 and mount--if for very close study1 in glycerine--if injected and for a 8show0 slide1 use balsam4 #df4 ,tongue4--,harden in chromic acid1 imbed and cut transverse sections in paraffine4 ,as1 however1 the paraffine is apt to get entangled amongst the papill1 whence it is afterwards with difficulty dislodged1 it will be as well before imbedding to soak the tongue in strong gum for a few minutes1 and afterwards immerse in alcohol till the gum becomes hardened1 so that the delicate papill may thus be protected from the paraffine by a surface-coating of gum4 ,the best staining agent is picro-carmine 7 #db74 ,sections of cat's tongue near the root1 when thus stained1 furnish splendid objects4 ,sections should also be made of the taste-bulbs1 found on the tongues of rabbits4 ,these are small oval prominences1 situated one on each side of the upper surface of the tongue near its root4 ,they should be snipped off with scissors1 and vertical sections made in the direction of their long axis4 ,stain with carmine or picro-carmine1 and mount in glycerine or balsam4 #dg4 ,vegetable ,ivory4--,after prolonged soaking in cold water may readily be cut in the microtome4 ,the sections should be mounted in balsam1 and though not usually regarded as polariscopic objects1 nevertheless1 when examined with the selenite1 yield very good colours4 #dh4 ,wood4--,shavings of extreme thinness may be cut from large pieces or blocks of timber1 by means of a very sharp plane4 ,in this way very good sections may be procured of most of the common woods1 as oak1 mahogany1 8glandular wood0 of pine1 etc4 ,where however1 the material to be operated upon takes the form of stems1 roots1 etc41 of no great thickness1 they should1 after having been reduced to a suitable consistence 7 #d71 be imbedded in paraffine1 and cut in the microtome4 ,before imbedding it must not be forgotten to immerse the wood to be cut in weak gum-water 7 #aa71 this precaution being of great importance1 especially in the case of stems1 etc41 the bark of which is at all rough and sinuous4 ,if the sections are to be mounted unstained1 they are usually put up in weak spirit 7 #bf74 ,a very general method also of dealing with this class of objects is to mount them dry 7 #bf74 ,this plan1 however1 cannot be recommended1 for however thin the sections may be1 the outlines1 when this process is adopted1 always present a disagreeable black or blurred appearance4 ,to avoid this we may have recourse to ,canada balsam1 but the ordinary method of employing it must be slightly modified1 a drop of chloroform being substituted for the clove oil 7 #bc71 otherwise this latter agent will cause the section to become so transparent as to render minute details of structure difficult to recognize4 ,a better plan1 perhaps1 is to stain the section with carmine or logwood1 and mount in balsam by the ordinary process4 ,the best course to follow1 however1 especially in the case of transverse sections1 is the double staining method4#ah ,for this purpose the sections in the first place must be subjected to the action of a solution of chloride of lime 7#a_/d oz4 to a pint of water7 until they become thoroughly bleached4 ,they must then be soaked in a solution of hyposulphite of soda 7one drachm to four ounces of water7 for an hour1 and after being washed for some hours1 in several changes of water1 are to be transferred for a short time to methylated spirit4 ,some red staining fluid is now to be prepared by dissolving half a grain of ,magenta crystals in one ounce of methylated spirit4 ,a little of this solution being poured into a small vessel of white porcelain 7 #ad71 the sections are to be immersed in the dye for about thirty minutes4 ,they are now to be removed1 and after rapid rinsing in methylated spirit to remove all superfluous colour1 they must be placed in a blue staining fluid made by dissolving half a grain of aniline blue in one drachm of distilled water1 adding ten minims of dilute nitric acid and afterwards sufficient methylated spirit to make two fluid ounces4 ,the sections must be permitted to remain in this solution for a very short time only1 one to three minutes being generally sufficient1 for as the action of the dye is very energetic1 it will1 if too long exposure be allowed1 completely obliterate the previous coloration by the magenta4 ,after being again rapidly rinsed in methylated spirit1 as much of this as possible must be drained off1 and the sections put into oil of cajeput1 whence1 in an hour1 they may be transferred to spirits of turpentine1 and after a short soaking1 mounted in balsam4 ,footnote #ah3 ,see a paper by ,mr4 ,styles in the 8,pharmaceutical ,journal10 also 8,monthly ,microscopical ,journal0 for ,august1 #ahge4 ,for a very exhaustive paper on this subject by the late ,dr4 ,beatty1 of ,baltimore1 ,md41 see 8,american ,journal of ,microscopy0 for ,june1 #ahgf4 ,if the student will carefully carry out the above process1 his trouble will be amply repaid by the beautiful results obtained1 for by its means he may1 with ease1 prepare for himself a series of slides of such value as to constitute a worthy addition to his cabinet4 ,the preceding list by no means represents all the objects1 sections of which will be found interesting to the microscopic student4 ,such was not its purpose--had it been so1 the enumeration might have been prolonged almost indefinitely4 ,the end in view was to bring under the notice of the reader only those substances the cutting of which is accompanied by difficulty2 and even of this class the space at our disposal has been so limited that we have been unwillingly compelled to pass over many1 and dwell only on such as possess a typical character4 ---------------------------------------- -------------------------------- ,,notes4 ---------- ,,note ,a41 ,page #ad4 ,,rangoon oil is not found in this market4 ,it is a variety of naphtha or petroleum found at ,rangoon1 in ,asia1 and contains a variable percentage of solid paraffin4 ,kerosene with a very little paraffin dissolved in it1 would undoubtedly answer the same purpose4 ,good sperm oil or tallow 7free from salt7 will serve quite as well4 ,it is scarcely necessary to caution the reader that all oily matter should be removed from the knife before it is used for cutting sections4 ,this is best effected by dipping it in hot water and carefully wiping it4 ,,note ,b41 ,page #ae4 ,,methylated spirit is alcohol which contains a small percentage of methyl4 ,this renders it unfit for use in the manufacture of liquors or even chloroform1 but does not injure it as a preservative fluid4 ,the scientific men of ,great ,britain have the privilege of obtaining this fluid free from duty1 and consequently they make very general use of it4 ,in this country the student of science has no such privilege1 and must use the more expensive alcohol4 ,this however is but of a piece with other restrictions placed upon scientific pursuits in this country1 where men like ,marshall ,jewell and ,hannibal ,hamlin have influence enough to pass laws which prohibit the exchange by mail of microscopic specimens1 which pass freely in every other civilized country4 ,true methyl alcohol1 or methylated spirits1 is not to be had in this country1 and therefore whenever this liquid is directed to be used in ,english books the ,american microscopist must substitute good alcohol4 ,what is sold for 8methyl alcohol0 is wood spirit or wood naphtha1 and will not serve the purposes of the microscopist1 though it answers well enough for spirit lamps1 making varnishes1 etc4 ,,note ,c41 ,page #bj4 ,,the method described in the text is generally known as the 8free-hand0 method1 and although it is not generally employed for the production of cabinet specimens or slides that are intended for sale1 yet it possesses so many advantages that every student should endeavor to acquire the art of cutting sections without the use of the microtome4 ,for purposes of study such sections are quite equal to the best of those usually found on sale1 and for the encouragement of beginners we may add that we have seen sections cut by the free-hand method which for size1 thinness and accuracy1 excelled any that we have ever seen produced with the microtome4 ,indeed ,schffer distinctly affirms that no microtome can equal the skilled hand in the production of thin sections4 ,,note ,d41 ,page #bb4 ,,the mere existence of a binding screw should be no objection1 and where bushings are employed it is sometimes necessary4 ,but as the author well observes1 a binding screw cannot be used to secure histological preparations4 ,,note ,e41 ,page #bb4 ,a ,,still better system is where the section-knife is held in a frame which slides on the plate so that the edge is kept just above the surface4 ,in this way the edge of the knife is never dulled by grinding on glass or metal4 ,a common mistake in this form1 however1 is to raise the cutting edge too far above the surface of the plate4 ,this gives rise to great irregularities4 ,,note ,f41 ,page #bb4 ,,as the size of the sections which it may be desired to cut1 varies within wide limits1 the best microtomes made in this country are furnished with as many as three tubes or 8bushings10 fitting one within the other1 and in this way the hole may be partially filled up and thus reduced in size4 ,this enables us to obtain a range of from one inch and a quarter1 suitable for large histological preparations1 to one-eighth of an inch for such objects as hair sections4 ,,note ,g41 ,page #cg4 ,,knives ,,for ,,cutting ,,sections4 ,,success in cutting sections depends more upon the excellence of the knife that is used than upon any other one point1 and therefore the art of keeping the knife in good order is one which should be acquired by every microscopist1 even at the cost of considerable time1 study and labor4 ,as a stepping stone to the acquisition of this art1 there are certain general principles which must be thoroughly understood before we can hope for success in practice4 ,these principles are simple1 and when once clearly stated1 quite obvious1 but they are frequently overlooked4 ,cutting instruments act in two ways--either as simple wedges or as a series of wedges1 the latter being generally known as the saw-like action4 ,it is frequently stated in school philosophies that the edges of all cutting instruments are toothed like a saw1 and that they act like a saw2 this is evidently not the case with many1 such as the axe1 the chisel1 the plane1 etc41 and it is not even true of several to which it is frequently applied1 such as the razor1 the penknife1 etc4 ,the action can be said to be 8saw-like0 only when the teeth act as independent wedges and remove a small portion of the substance acted upon1 the portion being known as saw-dust4 ,now in cutting sections of wood with a sharp razor1 where but a single stroke is used to carry the cutting edge across a section1 say half an inch in diameter1 the edge of the razor does not act like a saw2 none of the material is removed except the section itself2 in other words1 there is no saw-dust4 ,that the edge of the knife or razor is not even1 is very easily proved by means of the microscope1 but it will be found that the notches and projections form a series of lancet-shaped knifelets1 each one of which acts just as does the blade of a penknife when drawn over a piece of wood or a quire of paper4 ,now if we lay a quire of paper on a board and draw the edge of a penknife over it1 we will cut down through the paper1 not by sawing but by a moving wedge4 ,it is precisely in this way that the little lancet-shaped teeth on the edge of a razor act when the latter is used to cut a section4 ,if we further examine the edge of the razor1 we will find that the bottoms of the notches are comparatively blunt2 if therefore we press the razor directly forward we soon press these blunt portions of the general edge against the material to be cut1 and the resistance becomes so great that the material is actually crushed or torn4 ,this would not happen if we had an absolutely perfect edge--one without any notches4 ,this being practically unattainable1 however1 we must endeavor to make up for it by a sawing motion1 7though not a sawing action7 at the same time seeking to avoid as much as possible those saw-like features which render this motion necessary4 ,we have dwelt at length upon this point because so much has been written comparing the edge of a razor to that of a saw1 that some persons actually advise us to give the edges of our knives and razors a saw-like character1 under the impression that by so doing they will work better4 ,this is a fallacy2 the best work will be obtained from the smoothest and most perfect edge1 provided the latter is thin enough4 ,if the material of which our cutting instruments are made would allow it1 that is to say if it was perfectly hard1 perfectly rigid and incapable of being crushed or torn apart1 the proper shape of a cutting instrument would be a wedge of the most acute form possible4 ,but since the steel which we use is limited in its hardness and its power of resisting crushing and bending influences1 the blades of our knives must have a certain strength or thickness1 depending upon the character of the material to be cut4 ,for very hard substances the knife must be stout and the edge ground to a comparatively obtuse angle2 for moderately soft substances1 such as wood1 the angle may be more acute1 while for very soft tissues the thinnest blade and the sharpest edge are most suitable4 ,illustration3 ,fig4 #a4 ,the various angles to which cutting tools of different kinds are ground are shown in the accompanying illustrations1 which explain themselves4 ,illustration3 ,fig4 #b4 ,in the diagrams just given1 the sides of the wedge are carried in straight lines to the very edge4 ,in practice1 however1 this is never done1 there being two strong objections to such a form4 ,in the first place if the sides were as shown in the figures1 every time the tool was ground or set1 the entire side would have to be ground off1 and this would involve great labor4 ,but another difficulty1 quite as great1 would occur in the use of the instrument1 for since the wedge keeps growing constantly and proportionately thicker1 the friction between the sides of the wedge and the material would rapidly become very great4 ,therefore most cutting edges are ground to a second angle1 much more obtuse than the first1 and it is this second angle which forms the true cutting edge4 ,and it is obvious that the mass of material required to carry out the ultimate angle in any case is wholly unnecessary1 for if the tool be strong enough at a b 7,fig4 #b7 it will certainly be strong enough at c d4 ,an extreme illustration of this principle is shown in the cold chisel used for cutting iron1 the edge of which is shown in ,fig4 #b1 and the angle of #hj to which it is ground is carried out by dotted lines4 ,the angle which the sides of the chisel 7not the sides of the extreme cutting edge however7 make with each other is #be4 ,illustration3 ,fig4 #c4 ,illustration3 ,fig4 #d4 ,there are two methods by which this change of angle may be made1 one of which is shown in the cold chisel just figured1 and the other in the razor of which a section is shown in figures #c and #d4 ,in the case of the cold chisel it will be seen that the tool is first formed to a thin straight wedge which is afterwards changed to one that is much more blunt4 ,this answers very well where the ultimate angle is comparatively large or blunt1 as is the case with penknives1 table-knives1 carving-knives1 etc4 ,but where the ultimate angle is very small this plan does not answer well1 and the method shown in ,fig4 #c is generally adopted4 ,here the ultimate angle is such that lines touching the extreme edge and the back of the blade are perfectly straight and form the actual cutting angle4 ,in this case1 therefore1 the relief is obtained by hollowing out the sides of the blade1 and this is done to various extents1 the extremes being shown in figures #c and #d4 ,fig4 #c shows a section of a razor ground on a stone #ab inches in diameter1 which is as large as is generally used for this purpose4 ,fig4 #d is a section of a razor ground on a four-inch stone--the smallest in general use4 ,this method of changing the angle is of course substantially the same as the first1 merely differing in the mechanical device used1 but it affords this important advantage that in the subsequent honing and stropping processes the back of the razor forms a perfect guide by which the ultimate angle may be determined4 ,this is not the case with the cold chisel or the carving-knife1 in both of which cases the eye and hand alone determine the cutting angle1 which is therefore apt to become irregular or even rounded--the worst form of all4 ,this will be more easily understood from the following engravings where ,a1 ,fig4 #e1 shows a penknife blade1 as applied to an oilstone for the purpose of giving it the final edge4 ,the angle here shown is considerably greater than that generally used1 but the principle is the same4 ,it is evident that if1 in moving the blade back and forth on the stone we allow it to rock or change the angle which the blade makes with the stone's surface1 the edge will become rounded as shown in ,fig4 #f--;a form which for delicate work is useless4 ,if the blade be laid down flat as at ,b1 ,fig4 #e1 the labor of wearing away the superfluous metal will be enormous4 ,but if the blade be hollow as ,fig4 #g1 7where the hollow is1 for clearness of illustration1 slightly exaggerated7 then the ultimate angle may be formed quickly and accurately1 there being no danger of the angles being changed on account of want of skill on the part of the operator4 ,illustration3 ,fig4 #e4 ,illustration3 ,fig4 #f4 ,illustration3 ,fig4 #g4 ,illustration3 ,fig4 #h4 ,in some cases one side is left quite flat and the other side is ground to two or sometimes three angles1 as in the carpenter's chisel1 a section of which is shown in ,fig4 #h1 where a a shows the angle made by the body of the blade2 b b the angle of the bevel formed by the grindstone1 and c c the angle of the cutting edge which is formed by the oilstone4 ,in this case the flat side ,a ,b forms a straight guide and enables the workman1 in cutting1 to make straight1 clean work4 ,in sharpening such a tool on the oilstone the flat side is always laid flat on the oilstone and merely smoothed off1#ai and the skill of the workman is chiefly shown in the accuracy with which he forms the angle c ,b c4 ,the dexterity with which skilled workmen can effect this by the hand alone is astonishing1 but in the hands of those who have had but little practice the edge infallibly becomes rounded as shown in ,fig4 #f4 ,therefore wherever a knife with a flat side is used1 no attempt should ever be made to grind this flat side on the hone4 ,such an attempt will almost always result in an edge so irregular that it will be almost impossible to cut a good section with it4 ,but if the under side of the knife be left truly flat1 we will have the very best tool that can be had for use with the microtome4 ,unfortunately1 however1 it is very difficult to get a knife with a truly flat surface1 that is1 one that is perfectly 8out of wind0 as mechanics say4 ,as a general rule the flat sides of knives are not true planes but irregularly curved surfaces2 consequently when laid on a plane surface1 such as the table of a microtome1 they rock1 and the edge is in contact with the table at some points and separated from it at others1 and the points which are in contact change as the knife is moved diagonally across the table4 ,this makes the section irregular and worthless4 ,but a really good knife with a perfectly true flat side is such a valuable tool that a good deal of effort may be profitably expended in getting it1 and when once obtained never let the flat side be touched by a grindstone1 or more than touched by a hone4 ,it is not absolutely necessary1 however1 that the sides of a delicate knife should be curved1 provided the knife is used for cutting very soft materials4 ,an angle of #aj or even #e gives a pretty stout blade when carried back three-quarters of an inch1 as may be seen by examining ,fig4 #a1 and the guiding action of the very thick back may be obtained by means of an artificial guide1 applied like the brass backs of tenon saws4 ,such an arrangement is shown in ,fig4 #i1 and has been found very effectual4 ,footnote #ai3 ,holtzapffel tell us that chisels that are required for paring across the end grain of moderately soft wood are considered to hang better to the work when they have a very slight keen burr or wire edge thrown up on the face or flat side of the tool4 ,but this does not apply to section knives4 ,when the knife is to be honed1 the back is applied and fastened by means of two or three set screws4 ,when laid on the hone1 the edge of the knife and the lower surface of the back form the guide and regulate the cutting angle4 ,in this way we can use a broad1 thin blade and yet secure great accuracy in honing it4 ,such a blade has this advantage also1 that it is not so liable to be rounded and thus injured by stropping as one in which the relief is obtained by hollowing out the sides4 ,illustration3 ,fig4 #i4 ,such1 then1 are the general principles which govern the construction of cutting tools1 including the section knives used by microscopists4 ,we will now give a few practical directions for selecting a knife and putting and keeping it in order4 ,in selecting a knife for cutting sections1 regard must be had to the texture of the material that is to be cut4 ,to attempt to cut delicate sections of soft tissues with the stout knives which are suitable for cutting sections of woody fibre would be to destroy the sections1 while to reverse the operation and cut sections of wood with thin1 delicate knives would result in the ruin of the knife4 ,we have seen a most excellent knife seriously injured by an attempt to cut material that was too hard for it4 ,the knife was very thin1 and had proved most excellent in cutting sections of such material as kidney1 liver1 etc4 ,an attempt was made1 against our protest1 to cut a section of an apple-shoot1 the wood of which was mature4 ,before the knife had gone half way across1 it bent1 dug into the wood and broke1 leaving an ugly gap in the middle4 ,experienced section-cutters know this very well1 but young microscopists are not so familiar with the facts just stated1 and the point is too important to be overlooked4 ,those1 therefore1 who devote themselves to microscopical studies1 or who expect to make sections of materials of several kinds1 differing in hardness1 etc41 must provide themselves with knives of different degrees of strength4 ,for common work1 good razors are as good as anything1 provided they can be obtained with straight edges4 ,where razors are not suitable1 recourse must be had to the surgical instrument maker1 though we are sorry to say that there are but few in this country that know how to forge1 temper and grind a decent knife4 ,most of our dealers in instruments do not make the instruments they sell2 they import the goods they sell with their names stamped on1 and thus get a reputation as manufacturers2 a special order they are unable to fill respectably4 ,there are some exceptions1 but of the majority of dealers what we have written above is true4 ,the points which specially demand attention in a knife for cutting sections are these3 #a4 ,quality of the steel used2 #b4 ,temper2 #c4 ,form of the blade4 ,of the quality of the material of which a knife is made1 nothing can be determined except by actual trial4 ,the old tests of staining with acids1 examining with the microscope1 etc41 are worthless1 or at least too crude and uncertain to be of any practical value4 ,color changes with the degree of polish that is produced1 and1 in short1 there is no reliable guide4 ,the purchaser must depend entirely upon the reputation of the manufacturer4 ,there is plenty of good steel to be found2 the trouble lies with the cutlers4 ,they are careless and in haste1 and as a consequence they burn the steel or fail to work it sufficiently1 and the result is a useless tool4 ,the steel may be of the very best quality1 however1 and well forged1 and yet the knife may fail from being badly tempered--too soft or too hard4 ,if too soft1 the edge is soon dulled2 the knife requires to be frequently honed1 and the time wasted in keeping it in order is a serious drawback4 ,if too hard1 it is impossible to give it a keen edge1 for the metal crumbles away as soon as it is honed or stropped very thin1 and the edge becomes ragged and dull4 ,good steel1 well forged1 may be so tempered that it will neither crumble nor become rapidly dull4 ,much may be learned on this point from careful inspection of the edge1 and trial on a piece of horn1 such as an old razor handle4 ,when drawn over a clean piece of horn once or twice the edge of a soft knife is completely dulled2 if well-tempered it should scarcely lose its keenness4 ,again1 when laid flat on the thumb nail and pressed1 the edge ought to bend up without breaking or crumbling1 and at once1 when the pressure is removed1 resume its original shape4 ,the extent to which extreme hardness and durability1 or toughness1 may be combined1 is well shown in the famous ,toledo sword-blades4 ,one of these blades will shear through an iron nail without having its edge perceptibly dulled1 and yet so tough and springy is it that it may be coiled up into a hoop of several folds without breaking or receiving any permanent set4 ,if we could only get section knives of stuff like this1 it would be a pleasure to work with them4 ,after all1 however1 the only test of these two points1 material and temper1 is a fair trial in actual practice4 ,of the form of the blade1 however1 it is easy to judge1 and there are a few points which are frequently overlooked and which give rise to errors that are attributed to other causes4 ,in the text we are told that 8,it is essentially necessary that the back and edge of the blade be strictly parallel to each other40 ,the author undoubtedly knew what the correct form should be1 but the definition he has given is not a correct mathematical statement of the conditions involved4 ,these are as follows3 ,the edge must form a straight line1 and both the edge and the under side of the back must lie in the same plane4 ,let us consider these conditions somewhat carefully4 ,since the hole in which the material to be cut is imbedded1 is always circular1 and since the blade is generally pressed forcibly against the table of the microtome1 it is obvious that if the edge of the knife be curved it will sink into the hole to a greater or less depth according as it is further from the centre of the hole or nearer to it4 ,to explain this let us refer to the greatly exaggerated drawing given in figure #aj where the edge of the knife1 a1 b1 is shown in two different positions covering the hole of the microtome4 ,the least degree of reflection will show that as the knife passes towards the centre from a b to a b1 it will have a tendency to turn on the back as on a hinge1 and the middle of the edge will sink deeper into the hole as it approaches the centre of the latter4 ,the section will therefore vary in thickness and prove useless4 ,this difficulty can be obviated only by the use of a straight edge like e f1 which will always lie in the same plane4 ,illustration3 ,fig4 #aj4 ,if the knife were perfectly rigid1 and the curved edge and back lay entirely in the same plane1 this difficulty would not occur to any great extent4 ,but since a curved edge rarely lies wholly in the plane of the back of the knife1 and since the blades of most knives1 especially those thin ones used for cutting sections of soft tissues1 yield a little to pressure1 and since this pressure is never exactly the same1 it is impossible to prevent irregularities from occurring4 ,while it is not necessary that the back of the knife and the cutting edge should be parallel to each other1 it is absolutely necessary that they be in the same plane1 or1 as mechanics say1--8out of wind40 ,if this condition be not observed1 the blade will rock on the microtome table as it passes over it1 and irregularity in thickness of section will result4 ,a slight knowledge of geometry will enable any one to see that these statements are strictly accurate4 ,as regards other points in the form of the knife1 we refer to what has been previously said when discussing the general principles which should govern the construction of cutting tools4 ,we now proceed to give a few practical directions for sharpening knives and razors and keeping them in order4 ,section knives1 during the process of sharpening1 are subjected to three distinct processes3 #a1 ,grinding2 #b1 ,honing2 #c1 ,stropping4 ,grinding is one of the most important1 though it is probable that it will rarely be undertaken by the microscopist himself4 ,more knives and razors are spoiled in grinding than in any other way4 ,we have now in our possession an excellent knife1 which in an evil hour we entrusted to a ,new ,york cutler1 and received it back utterly ruined1 the temper being entirely taken out of the blades6 ,some of our readers may wonder at this1 but unfortunately it is too true4 ,the cutler1 to save time and trouble1 too frequently holds the blade against the stone with such force that it becomes over-heated1 especially when he is a little careless and allows the supply of water to fall short4#bj ,the owner does not find this out until he discovers that the knife is ruined1 because nothing is more easy than to cool the blade and grind off the tell-tale blue spots4 ,when charged with his rascality1 the cutler always denies it and lays the blame on a 8soft spot in the steel0--a miserable subterfuge--too transparent to deceive the least experienced4 ,footnote #bj3 ,nothing is more easy than to heat a thin rod or stout wire red hot by holding it against a dry grindstone rapidly revolving4 ,we have often kindled fire in this way4 ,the only protection against this is either to entrust the knife to a man of known carefulness and integrity1 or to stand over him while he does it4 ,if the knife be ground under the owner's eye1 no fear need be entertained1 because it is easy to insist upon the use of plenty of water4 ,the grindstone used for section knives should be of fine grain1 and it should run true and be very straight across the face1 otherwise it will be impossible to grind the knife true1 and this1 as we have seen1 is a necessity4 ,every microscopist that expects to do much at cutting sections must learn to hone his own knife or razor4 ,of the various hones in use the famous ,turkey oilstone is said to be altogether the best4 ,it is1 however1 very difficult to get it genuine and in sufficiently large pieces4 ,we therefore use the ,german hone-slate1 a softer1 yellow stone of wonderful fineness and cutting power4 ,the ordinary whetstones are altogether too coarse1 and as for artificial stones and strops1 they may do for coarse work and common razors for scraping1 but they will not do for knives used for section-cutting4 ,if any of our readers should be so fortunate as to possess a good1 old-fashioned ,turkey oilstone with a fair sized surface1 let them think much of it4 ,it is invaluable4 ,years ago1 when working on some investigations that required the use of very sharp knives1 we were offered1 by an old ,english carpenter1 the use of a real ,turkey stone4 ,we have never since found anything that did its work so quickly and so well4 ,to merely mention the substitutes for ,turkey oilstone would fill some pages4 ,we therefore confine ourselves to the ,german hone4 ,it is obtained from the slate mountains in the neighborhood of ,ratisbon1 where it occurs in the form of a yellow vein running vertically into the blue slate1 sometimes not more than an inch in thickness1 and varying to twelve to eighteen inches4 ,after being quarried it is sawed into thin slabs1 which are usually cemented to a similar slab of the blue slate as a support1 and the combined stones are then set in a wooden frame and fitted with a cover1 also of wood4 ,unlike the ,turkey oilstone1 the ,arkansas stone1 and some others1 the ,german hone is soft and easily scratched and worn4 ,it must therefore be carefully preserved1 and as the flatness of the hone is an important point1 it should never be used for anything but section knives4 ,having purchased a hone1 the first thing to do is to see that it is perfectly true2 that is1 that its surface is a perfect plane4 ,if hollow or twisted1 it is useless until made straight4 ,it may be tested by means of two steel or wood straight-edges1 and the method of doing this1 which is very simple but difficult to describe1 the microscopist can learn from any cabinet maker or carpenter4 ,if the hone be not true it must be made so1 and this is best done by grinding it with emery on a slab of marble or1 better still1 a plate of cast iron which has been planed true4 7,waste castings with planed surfaces may be found in most machine shops1 and may be either borrowed or purchased for a small sum47 ,if the hone is very uneven1 coarse emery may be used at first2 then finer must be taken1 and so on until the surface of the hone is not only true but very smooth4 ,this involves considerable labor1 but it cannot be avoided if a true edge as well as a sharp one is desired1 and hence our advice to use the hone for nothing but section knives4 ,accuracy in a penknife or a razor for shaving is of no consequence2 in a section-knife it is a sine qua non4 ,the surface of the hone must not only be true and smooth1 it must also be clean and free from dust and grit1 a single particle of which may spoil the work of hours4 ,it should therefore1 when not in use1 be kept constantly covered4 ,it is always used with oil1 and this oil should be of a kind that does not readily dry up4 ,good sperm is excellent1 and so is purified neat's-foot oil4 ,avoid kerosene1 soap and water1 and similar fluids1 which are so frequently recommended1 especially under the guise of new discoveries4 ,they have all been tried and found wanting4 ,after use1 the stone should be carefully wiped clean1 fresh oil being applied when it is next used4 ,it must never be used without a liberal supply of oil1 otherwise it will become glazed and will no longer act on the steel4 ,the hone being in good order1 the blade is laid flat on it and moved over its surface with circular sweeps4 ,the method of doing this is easily acquired1 and is best learned by watching an expert cutler at work4 ,if we could only hit it1 the perfection of this operation would be to wear down the sides of the blade until they just met2 they would then form a keen and perfect edge4 ,unfortunately we cannot always hit this point exactly2 we are apt to overdo the matter just a little1 and then comes up the bte noir of beginners--the 8wire edge40 ,this is caused by the metal of the blade bending away from the hone as soon as it becomes of a certain degree of thinness4 ,once it does this it cannot be worn off by the hone1 and the only way to remove it is to draw the edge of the knife or razor across a piece of horn or hard wood4 ,after removing the wire edge in this way1 give the blade one or two sweeps on the hone and then strop it4 ,if the blade be very soft1 the wire edge comes very quickly and easily1 and is very hard to get rid of4 ,on very hard blades the wire edge is not so apt to make its appearance4 ,it comes1 however1 on very excellent blades4 ,it may be avoided in a measure by driving the blade edge-first over the hone1 and indeed the blade should always be sharpened most in this way4 ,and since the backward and forward strokes are always nearly equal1 as regards space passed over1 this is accomplished by exerting a greater pressure on the forward than on the backward stroke4 ,this wire edge is a nasty thing when it breaks off on the hone4 ,unless removed it will very speedily ruin a fine knife1 therefore look out for it and wipe off the hone carefully if you have any suspicion that particles of steel have broken off the blade and got on to it4 ,in honing1 as in everything else1 however1 nothing but practice will impart skill1 and he who intends to become an expert should practice on a few old razors1 grinding1 honing and stropping them himself1 until he has acquired the art of giving them an edge far keener than most of the razors ordinarily used for shaving4 ,the last operation to which the knife is subjected is that of stropping1 and as the blade should be stropped after every section1 it becomes important that our tools should be good and that we should know how to use them4 ,by having two or three knives we can always avoid grinding and honing the blades ourselves1 for it is then easy to hire the work done1 and half a dozen knives will last a careful worker a long time with merely the aid of a good strop4 ,but the strop he must use himself4 ,fortunately no great skill is required in stropping1 but the strop must be a good one and is best home-made4 ,our readers have doubtless seen the 8,cheap ,john0 strop-vendors take a rough table knife1 strop it on one of their 8patent0 strops and cut a hair with it4 ,nevertheless such a knife1 sharpened in that way1 would not cut good sections1 and such a strop is not just the thing for giving the finishing touch to a section-knife1 even though the label does say that it is 8intended for surgical instruments40#ba ,footnote #ba3 ,the finest emery paper1 glued on a strip of wood and used as a strop1 will impart to a razor an edge sufficiently keen to enable it to remove the beard1 and if paper three or four degrees coarser be used1 a very dull knife or razor may be sharpened1 and afterwards stropped on the finer emery until it is keen enough to cut a hair4 ,but it will be found that cutting edges produced in this way are not smooth enough for section-cutting4 ,the strop should never be used with the intention of removing metal so as to thin the edge of the knife4 ,this is the proper function of the hone1 and those who depend most on the hone and least on the strop1 will always succeed best4 ,the strop is used in the first place for smoothing off the edge1 and in the second for removing that incipient dullness which always comes from even the slightest use4 ,it is true that in the latter case the strop trespasses somewhat on the functions of the hone1 but only to a very slight extent1 and stropping should never be carried so far as to require more than a very few strokes4 ,illustration3 ,fig4 #aa4 ,illustration3 ,fig4 #ab4 ,the best material for a strop is good calf-skin1 well tanned1 and firmly glued to a strip of wood with the hair side out4 ,the leather should be hard1 otherwise it will rapidly round the edge of the knife4 ,the way in which this occurs is readily understood from figures #aa and #ab4 ,in ,fig4 #ab the leather is seen to rise up behind the edge of the blade as the latter passes over it1 so that instead of two plane facets meeting at an angle of from #ae to #bj as left from the hone1 7,fig4 #ab7 the edge has become considerably rounded and the ultimate angle of the cutting edge is nearly or quite doubled4 ,the hardest and firmest leather should therefore be chosen1 avoiding of course any leather that has been made hard and unpliable by the action of water or other agents4 ,two sides will be found enough for a strop4 ,on one the leather should be kept clean1 while the other should be thoroughly impregnated with fine grained1 but very hard rouge or crocus4#bb ,rouge is an artificial oxide of iron prepared by exposing sulphate of iron to heat4 ,the hardness of the resulting powder depends upon the temperature to which it has been exposed1 and this temperature is very well indicated by the color which the rouge assumes4 ,bright red or crimson rouge is soft and will not cut steel2 hard rouge1 suitable for polishing steel1 is purple in color1 and this quality should therefore be chosen4 ,great care should be taken to see that it is free from gritty particles1 and it should be well rubbed into the leather in a dry state4 ,all mixtures of grease and oil with abrasive substances should be eschewed4 ,if the leather be of good texture and the rouge hard and fine1 a very few strokes will suffice to impart the last degree of smoothness and keenness to the blade4 ,footnote #bb3 ,rouge may be purchased from dealers in watch-makers' tools4 ,those who cannot procure it readily may very easily prepare it for themselves4 ,full directions may be found in the 8,amateur's ,handbook40 ,new ,york3 ,industrial ,publication ,company4 ,since grit and dust would soon spoil the strop1 it should be kept carefully covered and protected4 ,the rouge will require occasional renewing1 which may be done by sprinkling a little lightly over the surface and rubbing it in with the finger4 ,consequently we find that the best and most convenient holder for rouge is a bottle with some fine but porous fabric tied over the mouth of it1 forming as it were a sort of dredge4 ,over the bottle mouth and its cover should be tied a paper cap to keep out dust4 ,we have thus endeavored to give1 in as simple a manner as possible1 such information as will guide the microscopist to the acquisition of skill in this most important but generally despised department of his art4 ,we are told by the biographer of ,swammerdam that a great deal of his success was to be attributed to his skill in sharpening his fine knives and scissors4 ,the same is also stated of other noted workers1 and yet none give even the slightest directions to the novice who desires to follow in their footsteps4 ,there is not to our knowledge a single book in the ,english language which treats fully of this subject1 with perhaps the exception of ,holtzapffel's work on 8,mechanical ,manipulation10 and this has long been out of print4 ,as previously stated1 however1 it is only by practice that the necessary finger-skill can be acquired1 but this skill is well worth acquiring at any cost4 ,the man who depends upon cutlers and knife grinders will never make satisfactory progress4 ,,note ,h4 ,we are inclined to believe that the difficulty of enclosing glycerine does not arise from the dissolving action of this liquid1 so much as from the great adhesiveness which exists between it and glass4 ,oily cements are of course attacked by glycerine1 but shellac and several other gums are insoluble1 and drying oils1 if well oxidized are also insoluble4 ,where cells are used they must be first firmly attached to the clean slide1 and the cement should also be brought into direct contact with the clean cover4 ,glycerine does not evaporate at ordinary temperatures1 and consequently wherever the slide or cover is soiled with it1 no cement will ever adhere until the glycerine has been wiped off4 ,there is no prospect of its drying4 ,,note ,i4 ,page #dh4 ,the solution here referred to1 and which is known as ,kleinenberg's solution1 is made in the following way3 7#a47 ,make a saturated solution of crystallized calcium chloride in #gj per cent4 alcohol1 and add alum to saturation4 7#b47 ,make also a saturated solution of alum in #gj per cent4 alcohol4 ,add 7#a7 to 7#b7 in the proportion of #a3h4 ,to the mixture add a few drops of a saturated solution of hmatoxylin in absolute alcohol4 ,this solution may be used in very many cases for staining sections1 in place of the ordinary watery solution of logwood alum4 ,it may1 if required1 be diluted with the mixture of #a and #b4 ,the stained sections are placed at once in strong spirit4 ---------------------------------------- -------------------------------- ,,index4 ,acetic acid1 #ch ,adipose tissue1 #fc ther microtome1 #bd ,air-bubbles1 #dj1 #ee1 #fb ,alcohol1 #ag1 #ai absolute1 #ed ,balsam1 ,canada1 #df1 #ea to clean from slide1 #ee ,beale's carmine fluid1 #cc ,bell's cement1 #da ,blue staining fluid1 #fj ,bone1 #af1 #eg decalcified1 #eh ,bottles for media1 c41 #dh ,brain1 #ei ,brunswick black1 #da ,capillary attraction1 #ee ,carmine staining1 #cb ,carpenter1 ,dr41 #cg1 #da ,cartilage1 #fj ,cells1 to make1 #ei ,centring slide1 #ch ,chloroform-balsam1 #ea1 #ed ,chromic acid1 #ag ,clove oil1 #ea1 #ed ,coffee berry1 #fb ,cover1 applying1 #cg ,german plan1 #ci ,crochet-needle holders1 #ci ,double staining1 #gc ,dry mounting1 #eh1 #fe1 #gb ,fat1 #fc ,finishing slide1 #ed ,fibro-cartilage1 #fb ,freezing method1 #db-dg ,fresh tissues1 to cut1 #ae-ag ,fruit stones1 #eh ,gardner1 ,mr41 #be1 #ca ,gelatine cement1 #da ,glycerine1 #cg1 #ch ,gold staining1 #eh ,gum1 imbedding in1 #bb1 #ff strong1 #dc weak1 #ca1 #ga ,hair1 #fc-fi ,hmatoxylon1 see ,logwood ,hand-sections1 #ai ,hardening agents1 #ai ,hoggan1 ,f4 ,elizabeth1 ,dr41 #fa ,hone1 #bf1 #eg ,horn1 hoofs1 c41 #af1 #fd ,hyaline cartilage1 #fb ,ice1 for freezing1 #dc ,injections1 to harden1 #ai ,ink staining1 #gj ,intestine1 #db1 #dc1 #fd ,iron staining1 #fa ,kay1 ,j4 ,a41 ,mr41 #eb ,kidney1 #ag ,klein's lifter1 #ce ,knife1 section1 #be1 #cj ,leaves1 c41 to cut1 #ab ,ligaments1 intervertebral1 #fb ,lime1 carbonate of1 #cg ,liver1 #fe ,logwood staining1 #dg ,lung1 #dc1 #fe ,martindale's logwood fluid1 #dg ,media1 mounting1 #ch ,methylated spirit1 see ,alcohol ,microtome1 #ba choice of1 #bb ,microtome1 employment of1 #bi freezing1 #dc1 #dd imperfection in1 #bc1 #df ,rutherford's1 #ca ,muscle1 #ff ,needles1 microscopical1 #ci ,orange-peel1 #fg ,ovary1 #fg ,papill of finger1 #fi ,paraffine1 adhering to sections1 #bg imbedding in1 #bj1 #bf mixture1 #bf rising in tube1 #bc shrinks in cooling1 #bi ,paul1 ,dr41 #gj ,pathological specimens1 #ai1 #fb ,picro-carmine1 #ei1 #fh1 #gb ,porcupine quill1 #fg ,potato1 #fg ,preparation of animal tissues1 #af vegetable tissues1 #ae ,prussian blue pigment1 #ch ,rangoon oil1 #ad1 #dg ,razors1 #bj1 #bf1 #bi1 #cj ,rush1 #gh ,rutherford's microtome1 #bd1 #ca 8,practical ,histology10 #dc ,salicylic acid1 #dd ,salt1 for freezing1 #de ,schfer's 8lifter10 #ce 8,practical ,histology10 #dh ,scissors1 section1 #ac ,sebaceous glands1 #fi ,section-cutter1 see ,microtome ,section-knife1 #bd ,sections1 thickness of1 #ca to dehydrate1 #eb to transfer1 #cc ,seeds1 #fc ,skin1 #fh ,sperm oil1 #dd ,spinal cord1 #fi ,spirit lamp for balsam1 #ec weak1 #cf1 #ei ,sponge1 #ga ,spoon1 section1 #ce1 #ed ,staining agents1 #ca ,strop1 razor1 #bf1 #bi ,stomach1 #ga ,sudoriferous glands1 #fi ,taste-bulbs1 #ga ,teeth1 #af1 #eh ,tongue1 #ga ,tubes1 collapsible1 #ef ,valentin's knife1 #ad ,vegetable ivory1 #gb tissues1 to prepare1 #ab ,vessels1 porcelain1 #cc ,water-bath1 cheap1 #bi ,whalebone1 #fd ,white zinc cement1 #ef ,wood1 #gb ---------------------------------------- -------------------------------- ,,catalogue ,,of ,books and ,periodicals ,,published ,,and ,,for ,,sale ,,by ,,the ,,industrial ,,publication ,,company1 #agf ,broadway1 ,new ,york4 ,any of these ,books may be obtained from any ,bookseller or ,newsdealer1 or will be sent ,free by mail to any part of the ,united ,states or ,canada ,,on ,,receipt ,,of ,,price4 ---------------------------------------- -------------------------------- ,the ,amateur's ,handbook of ,practical ,information1 ,for the ,workshop and the ,laboratory4 ,second ,edition4 ,greatly ,enlarged4 ,neatly ,bound #ae cents4 ,this is a handy little book1 containing just the information needed by ,amateurs in the ,workshop and ,laboratory4 ,directions for making ,alloys1 ,fusible ,metals1 ,cements1 ,glues1 etc42 and for ,soldering1 ,brazing1 ,lacquering1 ,bronzing1 ,staining and ,polishing ,wood1 ,tempering ,tools1 ,cutting and ,working ,glass1 ,varnishing1 ,silvering1 ,gilding1 ,preparing ,skins1 etc41 etc4 ,the ,new ,edition contains extended directions for preparing ,polishing ,powders1 ,freezing ,mixtures1 ,colored ,lights for tableaux1 ,solutions for rendering ladies' dresses incombustible1 etc4 ,there has also been added a very large number of new and valuable receipts4 ---------------------------------------- -------------------------------- ,rhymes of ,science3 ,wise and ,otherwise4 ,by ,o4 ,w4 ,holmes1 ,bret ,hart1 ,ingoldsby1 ,prof4 ,forbes1 ,prof4 ,j4 ,w4 ,mc,q4 ,rankine1 ,hon4 ,r4 ,w4 ,raymond1 and others4 ,with ,illustrations4 ,cloth1 ,gilt ,title4 #ej cents4 ---------------------------------------- -------------------------------- ,section-,cutting4 ,a ,practical ,guide to the ,preparation and ,mounting of ,sections for the ,microscope2 ,special ,prominence being given to the ,subject of ,animal ,sections4 ,by ,sylvester ,marsh4 ,reprinted from the ,london edition4 ,with ,illustrations4 #abmo41 ,cloth1 ,gilt ,title4 #ge cents4 ,this is undoubtedly the most thorough treatise extant upon section-cutting in all its details4 ,the ,american edition has been greatly enlarged by valuable explanatory notes1 and also by extended directions1 illustrated with engravings1 for selecting and sharpening knives and razors4 ---------------------------------------- -------------------------------- ,companion for ,cheap ,microscopes4 ,intended for those who have absolutely no knowledge of the ,microscope or how to use it4 ,price1 in ,boards1 #cj cents4 ,in ,cloth1 ,gilt ,title #ej cents4 ,this is a very elementary book1 giving very simple directions for using the ,microscope1 and for collecting1 preparing and mounting objects4 ---------------------------------------- -------------------------------- ,how to ,use the ,microscope4 ,a ,simple and ,practical ,book1 intended for beginners4 ,by ,john ,phin1 editor of 8,the ,american ,journal of ,microscopy40 ,second ,edition4 ,greatly ,enlarged1 with #ej illustrations in the text and #d full-page engravings printed on heavy tint paper4 #abmo41 ,neatly bound in ,cloth1 ,gilt ,title4 #ge cents4 ---------------------------------------- -------------------------------- ,the ,microscope4 ,by ,andrew ,ross4 ,fully ,illustrated4 #abmo41 ,cloth1 ,gilt ,title4 #ge cents4 ,this is the celebrated article contributed by ,andrew ,ross to the 8,penny ,cyclopdia10 and quoted so frequently by writers on the ,microscope4 ,carpenter and ,hogg1 in the last editions of their works on the ,microscope1 and ,brooke1 in his treatise on ,natural ,philosophy1 all refer to this article as the best source for full and clear information in regard to the principles upon which the modern achromatic ,microscope is constructed4 ,it should be in the library of every person to whom the ,microscope is more than a toy4 ,it is written in simple language1 free from abstruse technicalities4 ---------------------------------------- -------------------------------- ,diatoms4 ,practical ,directions for ,collecting1 ,preserving1 ,transporting1 ,preparing and ,mounting ,diatoms4 ,by ,prof4 ,a4 ,mead ,edwards1 ,m4 ,d41 ,prof4 ,christopher ,johnston1 ,m4 ,d41 ,prof4 ,hamilton ,l4 ,smith1 ,,ll4 ,d4 #abmo41 ,cloth4 #ge cents4 ,this volume undoubtedly contains the most complete series of directions for ,collecting1 ,preparing and ,mounting ,diatoms ever published4 ,the directions given are the latest and best4 ---------------------------------------- -------------------------------- ,common ,objects for the ,microscope4 ,by ,rev4 ,j4 ,g4 ,wood4 ,upwards of four hundred illustrations1 including twelve colored plates by ,tuffen ,west4 ,illuminated ,covers4 #ej cents4 ,this book contains a very complete description of the objects ordinarily met with1 and as the plates are very good1 and almost every object is figured1 it is a most valuable assistant to the young microscopist4 ---------------------------------------- -------------------------------- ,five ,hundred and ,seven ,mechanical ,movements4 ,embracing all those which are ,most ,important in ,dynamics1 ,hydraulics1 ,hydrostatics1 ,pneumatics1 ,steam ,engines1 ,mill and ,other ,gearing1 ,presses1 ,horology and ,miscellaneous ,machinery2 and including ,many ,movements never before published1 and several of which have only recently come into use4 ,by ,henry ,t4 ,brown1 editor of the 8,american ,artisan40 ,eleventh ,edition4 #a4jj4 ,this work is a perfect ,cyclopdia of ,mechanical ,inventions1 which are here reduced to first principles1 and classified so as to be readily available4 ,every mechanic that hopes to be more workman1 ought to have a copy4 ---------------------------------------- -------------------------------- ,the ,six ,days of ,creation4 ,the ,chemical ,history of the ,six ,days of ,creation4 ,by ,john ,phin1 ,c4 ,e41 editor of 8,the ,american ,journal of ,microscopy40 #abmo41 ,cloth4 #ge cents4 ---------------------------------------- -------------------------------- ,stories ,about ,horses4 ,just the ,book for ,boys4 ,with eight full-page engravings4 ,in ,boards1 #be cents4 ,in ,cloth #ej cents4 ---------------------------------------- -------------------------------- ,shooting on the ,wing4 ,plain ,directions for ,acquiring the ,art of ,shooting on the ,wing4 ,with ,useful ,hints concerning all that relates to ,guns and ,shooting1 and particularly in regard to the art of ,loading so as to ,kill4 ,to which has been added several ,valuable and hitherto ,secret ,recipes1 of ,great ,practical ,importance to the ,sportsman4 ,by an ,old ,gamekeeper4 #abmo41 ,cloth1 ,gilt ,title4 #ge cents4 ---------------------------------------- -------------------------------- ,the ,pistol as a ,weapon of ,defence1 ,in the ,house and on the ,road4 #abmo41 ,cloth4 #ej cents4 ,this work aims to instruct the peaceable and law-abiding citizens in the best means of protecting themselves from the attacks of the brutal and the lawless1 and is the only practical book published on this subject4 ,its contents are as follows3 ,the ,pistol as a ,weapon of ,defence4--,the ,carrying of ,fire-,arms4--,different kinds of ,pistols in ,market2 ,how to ,choose a ,pistol4--,ammunition1 different kinds2 ,powder1 ,caps1 ,bullets1 ,copper ,cartridges1 etc4--,best form of ,bullet4--,how to ,load4--,best ,charge for ,pistols4--,how to regulate the ,charge4--,care of the ,pistol2 how to ,clean it4--,how to ,handle and ,carry the ,pistol4--,how to ,learn to ,shoot4--,practical use of the ,pistol2 how to ,protect yourself and how to ,disable your antagonist4 ---------------------------------------- -------------------------------- ,lightning ,rods4 ,plain ,directions for the ,construction and ,erection of ,lightning ,rods4 ,by ,john ,phin1 ,c4 ,e41 editor of 8,the ,young ,scientist10 author of 8,chemical ,history of the ,six ,days of the ,creation10 etc4 ,second ,edition4 ,enlarged and ,fully ,illustrated4 #abmo41 ,cloth1 ,gilt ,title4 #ej cents4 ,this is a simple and practical little work1 intended to convey just such information as will enable every property owner to decide whether or not his buildings are thoroughly protected4 ,it is not written in the interest of any patent or particular article of manufacture1 and by following its directions1 any ordinarily skilful mechanic can put up a rod that will afford perfect protection1 and that will not infringe any patent4 ,every owner of a house or barn ought to procure a copy4 ---------------------------------------- -------------------------------- ,instruction in the ,art of ,wood ,engraving4 ,a ,manual of ,instruction in the ,art of ,wood ,engraving2 with a ,description of the ,necessary ,tools and ,apparatus1 and ,concise ,directions for their ,use2 ,explanation of the ,terms ,used1 and the ,methods ,employed for ,producing the ,various ,classes of ,wood ,engravings4 ,by ,s4 ,e4 ,fuller4 ,fully illustrated with ,engravings by the author1 separate sheets of engravings for transfer and practice being added4 ,new ,edition1 ,neatly ,bound4 #cj cents4 ---------------------------------------- -------------------------------- ,what to ,do in ,case of ,accident4 ,what to ,do and ,how to ,do ,it in ,case of ,accident4 ,a ,book for ,everybody4 #abmo41 ,cloth1 ,gilt ,title4 #ej cents4 ,this is one of the most useful books ever published4 ,it tells exactly what to do in case of accidents1 such as ,severe ,cuts1 ,sprains1 ,dislocations1 ,broken ,bones1 ,burns with ,fire1 ,scalds1 ,burns with ,corrosive ,chemicals1 ,sunstroke1 ,suffocation by ,foul ,air1 ,hanging1 ,drowning1 ,frost-,bite1 ,fainting1 ,stings1 ,bites1 ,starvation1 ,lightning1 ,poisons1 ,accidents from ,machinery1 and from the ,falling of ,scaffolding1 ,gunshot ,wounds1 etc41 etc4 ,it ought to be in every house1 for young and old are liable to accident1 and the directions given in this book might be the means of saving many a valuable life4 ---------------------------------------- -------------------------------- ,,bound ,,volumes ,,of ,the ,technologist1 or ,industrial ,monthly4 ,the eight volumes of ,,the ,,technologist1 or ,,industrial ,,monthly1 which have been issued1 form a ,mechanical and ,architectural ,encyclopdia of great value2 and1 when properly bound1 they form a most important addition to any library4 ,the splendid full-page engravings1 printed on tinted paper1 in the highest style of the art1 are universally conceded to be the finest architectural and mechanical engravings ever published in this country4 ,we have on hand a few complete sets1 which we offer for #af4jj1 handsomely and uniformly bound in cloth4 ,we have also a few extra sets of ,vols4 ,,iii to ,,viii inclusive4 ,these six volumes we offer for #h4jj bound in cloth4 ,as there are but a very few sets remaining1 those who desire to secure them should order immediately4 ,,note4--,the above prices do not include postage or express charges4 ,the set weighs altogether too much to be sent by mail4 ---------------------------------------- -------------------------------- ,just ,published4 #a ,vol41 #abmo4 ,neatly ,bound in ,cloth1 ,gilt ,title4 ,price #ge cents4 ,,how ,,to ,,use ,,the ,,microscope4 ,a ,simple and ,practical ,book1 intended for beginners4 ,,by ,,john ,,phin1 ,editor of 8,the ,american ,journal of ,microscopy40 ,second ,edition4 ,greatly ,enlarged1 with #ej illustrations in the text1 and #d full-page engravings printed on heavy tint paper4 ,,contents3 ,,what ,a ,,microscope ,,is4--,different ,kinds of ,microscopes4--,simple ,microscopes4--,hand ,magnifiers4--,the ,coddington ,lens4--,the ,stanhope ,lens4--,raspail's ,microscope4--,the ,excelsior ,microscope4--,twenty-five cent ,microscopes and how to make them4--,penny ,microscopes4 ,,compound ,,microscopes4--,different kinds of ,objectives4--,non-,achromatic ,objectives4--,french ,achromatic ,objectives4--,objectives of the ,english ,form4--,immersion ,objectives4--,focal ,lengths corresponding to the numbers employed by ,nachet1 ,hartnack and ,gundlach4 ,,how ,,to ,,choose ,a ,,microscope4--,microscopes for ,special ,purposes4--,magnifying ,power required for different purposes4--,how to judge of the quality of the different parts of the ,microscope4 ,,accessory ,,apparatus4--,stage ,forceps1 ,animalcule ,cage1 etc4 ,,illumination4--,sun ,light4--,artificial ,light4--,bulls-,eye ,condenser4--,side ,reflector4--,the ,lieberkuhn4--,axial ,light4--,oblique ,light4--,direct ,light4 ,,how ,,to ,,use ,,the ,,microscope4--,how to ,care for the ,microscope4 ,,how ,,to ,,collect ,,objects4--,where to find ,objects4--,what to ,look for4--,how to ,capture ,them4--,nets4--,bottle-,holders4--,spoo ns4--,new ,form of ,collecting ,bottle4--,aquaria for ,microscopic ,objects4--,dipping ,tubes4 ,,the ,,preparation ,,and ,,examination ,,of ,,objects4--,cutting ,thin ,sections of ,soft ,substances4--,sections of ,wood and ,bone4--,improved ,section-,cutter4--,sections of ,rock4--,knives4--,scissors4--,needles4- -,dissecting ,pans and ,dishes4--,dissecting ,microscopes4--,separation of ,deposits from ,liquids4--,preparing whole ,insects4--,feet1 ,eyes1 ,tongues1 ,wings1 etc41 of ,insects4--,use of ,chemical ,tests4--,liquids for ,moistening ,objects4--,refractive ,power of ,liquids4--,covers for ,keeping out ,dust4--,errors in ,microscopical ,observations4 ,,preservation ,,of ,,objects4--,general ,principles4--,recipes for ,preservative ,fluids4--,general ,rules for ,applying them4 ,,mounting ,,objects4--,apparatus and ,materials for3 ,slides1 ,covers1 ,cells1 ,turn-,table1 ,cards for ,making ,cells1 ,hot-,plate1 ,lamps1 ,retort ,stand1 ,slide-,holder1 ,mounting ,needles1 ,cover ,forceps1 ,simple ,form of ,spring ,clip1 ,centering ,cards1 ,gold-,size1 ,black ,japan1 ,brunswick ,black1 ,shellac1 ,bell's ,cement1 ,sealing ,wax ,varnish1 ,colored ,shellac1 ,damar ,cement1 ,marine ,glue1 ,liquid ,glue1 ,dextrine4--,mounting ,transparent ,objects ,dry4--,mounting in ,balsam4--,mounting in ,liquids4--,mounting of ,whole ,insects4--,how to ,get ,rid of ,air-,bubbles4--,mounting ,opaque ,objects4 ,,finishing ,,the ,,slides4 ,may be obtained from any ,bookseller or ,news ,agent1 or will be sent by mail1 postage paid1 on receipt of price4 ,,the ,,industrial ,,publication ,,company1 ,p4 #j4 ,box #dhge4 #agf ,broadway1 ,new ,york4 ---------------------------------------- -------------------------------- ,,genesis ,,and ,,geology4 -------------- ,,the ,,chemical ,,history ,,of ,the ,six ,days of ,creation4 ,,by ,,john ,,phin1 ,c4 ,e41 ,,editor ,,of 8,,the ,,american ,,journal ,,of ,,microscopy40 #a ,vol41 #abmo4 ,cloth4 #ge cents4 -------------- ,the following are a few of the ,opinions of the ,press3 ,this is a small book1 but full of matter4 99 99 99 ,we think this book is full of interest and value2 and as the discussions concerning the harmony of science and faith are rife at the present day1 we commend the reasonings of ,mr4 ,phin to the great number of readers and students who are investigating these subjects4--,the ,presbyterian 7,philadelphia74 ,the author gives a new solution of this difficult question1 and certainly presents many very plausible arguments in support of his theory4--,sunday-,school ,workman4 ,a very candid and ingenious essay4--,christian ,union 7,h4 ,w4 ,beecher's paper74 ,no one can read this book without compensation1 without becoming more thoughtful concerning the phenomena of creation2 and he need lose none of his reverence for the supremacy of the ,divine ,law4--,rural ,new ,yorker4 ,we could say much in commendation of ,prof4 ,phin's little book4 ,an intelligent reader can hardly fail to be interested in it1 and many might be benefited4--,country ,gentleman4 ,the book can not fail to interest even those who do not fully accept the theory it advocates4--,boston ,journal of ,chemistry4 ,it is a new scientific view of the matter4--,phrenological ,journal4 ,the book1 although not large1 will prove exceedingly interesting to all who have ever directed attention to this matter1 and contains more solid and suggestive thought than many voluminous treatises on the subject4--,insurance ,monitor4 ,the work is ingenious and original1 and presents many striking suggestions4--,american ,baptist4 ,we believe ,prof4 ,phin has started upon the correct basis1 and his theory is mainly tenable4 ,his views are presented in a manner which1 though terse1 is easily comprehended4--,daily ,guardian 7,paterson1 ,n4 ,j47 ---------------------------------------- -------------------------------- ,,the ,,young ,,scientist1 ,a ,practical ,journal for ,amateurs4 ,,issued ,,monthly4 ,price #ej ,cents per year4 ,it is characteristic of young ,americans that they want to be ,,doing something4 ,they are not content with merely knowing how things are done1 or even with seeing them done2 they want to do them themselves4 ,in other words1 they want to experiment4 ,hence the wonderful demand that has sprung up for small tool chests1 turning lathes1 scroll saws1 wood carving tools1 telegraphs1 model steam engines1 microscopes and all kinds of apparatus4 ,in nine cases out of ten1 however1 the young workman finds it difficult to learn how to use his tools or apparatus after he has got them4 ,it is true that we have a large number of very excellent text-books1 but these are not just the thing4 ,what is wanted is a living teacher4 ,where a living teacher cannot be found1 the next best thing is a live journal1 and this we propose to furnish4 ,and in attempting this1 it is not our intention to confine ourselves to mere practical directions4 ,in these days of knowledge and scientific culture1 the 8,why0 becomes as necessary as the 8,how40 ,the object of the ,,young ,,scientist is to give clear and easily followed directions for performing chemical1 mechanical and other operations1 as well as simple and accurate explanations of the principles involved in the various mechanical and chemical processes which we shall undertake to describe4 ,the scope and character of the journal will be better understood from an inspection of a few numbers1 or from the list of contents found on a subsequent page1 than from any labored description4 ,there are1 however1 three features to which we would call special attention3 ,,correspondence4--,in this department we intend to place our readers in communication with each other1 and in this way we hope to secure for every one just such aid as may be required for any special work on hand4 ,,exchanges4--,an exchange column1 like that which has been such a marked success in the ,journal of ,microscopy1 will be opened in the ,young ,scientist4 ,yearly subscribers who may wish to exchange tools1 apparatus1 books1 or the products of their skill1 can state what they have to offer and what they want1 without charge4 ,buying and selling must1 of course1 be carried on in the advertising columns4 ,,illustrations4--,the journal will make no claims to the character of a 8picture book10 but wherever engravings are needed to make the descriptions clear they will be furnished4 ,some of the engravings which have already appeared in our pages are as fine as anything to be found in the most expensive journals4 ,special ,notice4 ,as our journal is too small and too low-priced to claim the attention of news dealers1 we are compelled to rely almost wholly upon subscriptions sent directly to this office4 ,as many persons would no doubt like to examine a few numbers before becoming regular subscribers1 we will send four current numbers as a trial trip for ,,fifteen ,,cents4 -------------- ,,clubs4 ,where three or more subscribe together for the journal1 we offer the following liberal terms3 #c copies for #a4be #e #b4jj #g #b4ge #aj #c4ej ,advertisements1 #cj cents per line4 ,as postal currency has nearly disappeared from circulation1 we receive postage stamps of the lower denominations 7ones1 twos and threes7 at their full value4 ,postal orders are1 however1 much safer and more convenient4 ,to avoid delay and mistakes address all communications to 8,,the ,,young ,,scientist1 ,box #dhge1 ,new ,york10 and make all checks and orders payable to ,john ,phin4 ---------------------------------------- -------------------------------- ,,what ,,people ,,say ,,of ,,us4 ,in a letter to the ,editor1 ,oliver ,wendell ,holmes1 the genial 8,autocrat of the ,breakfast ,table10 says3 8,i am much pleased with the ,,young ,,scientist4 ,it makes me want to be a boy again40 8,it is a little publication1 calculated to call out and educate all the latent ingenuity and thirst for knowledge which the youthful mind possesses1 and we hope it will win its way into every household in the land40--,scientific ,press4 8,we have never seen a periodical1 designed for youth1 which came nearer to our ideal of what such a journal should be40--,canadian ,pharmaceutical ,journal4 8,the ,,young ,,scientist is one of the choicest publications for juvenile minds in this country4 ,every page treats on subjects of importance to young and old1 portrayed in a clearly comprehensive manner1 which at once interests the young idea in its careful perusal40--,lapeer ,clarion4 8,it seems to fill the bill40--,newport ,daily ,news4 8,it is pleasing to note that its youthful subscribers will not be misled by clap-trap advertisements or advertisements of patent medicines1 which will not be received at any price4 ,the ,,young ,,scientist is doing good work in setting its face against this class of humbugs40--,manufacturing and ,trade ,review4 8,the work is a copiously illustrated monthly1 and is full of practical hints that will instruct and amuse the young folks40--,industrial ,school ,advocate4 8,a small but elegant and very instructive monthly40--,pittsburg ,chronicle4 8,contains the best possible reading for the young of both sexes40--,ottawa ,journal4 8,we can safely recommend this magazine as one of the very best publications for the young folks40--,the ,independent1 ,fenton1 ,mich4 8,this journal occupies a new field1 and is needed to put the minds of our youth on the right track to secure a correct understanding of the nature of things40--,wayland ,press4 8,it is ably edited by ,john ,phin1 who will make a large place in the heart of the rising generation1 if he persists in his venture4 ,we hope his success in the field will be equal to the article furnished--first best40--,sunset ,chimes4 8,the articles are written in a popular1 readable style1 and profusely illustrated40--,akron ,city ,times4 8,the ,,young ,,scientist is excellent in conception1 and well designed to amuse and instruct young people40--,chicago ,evening ,journal4 8,the ,,young ,,scientist is a handsome monthly magazine1 each number containing about #af pages1 handsomely illustrated4 ,it will supply a place which has been heretofore unoccupied4 ,the copy before us comes fully up to the promise of the prospectus40--,the ,times1 ,iroquois1 ,mich4 8,it is a journal which should be in the hands of both young and old1 and is a great benefit to the young scientist as well as the advanced professor4 ,it is a thousand times more valuable than the dime novel series1 so much read by boys4 ,parents would do well to have it in their households40--,the ,iron ,home4 8,this publication is a new launch1 and it is very gratifying to witness the ableness which pervades its pages40--,amherst ,free ,press4 ---------------------------------------- -------------------------------- ,,the ,,american ,,journal ,,of ,,microscopy1 ,,and ,,popular ,,science4 -------------- ,,prospectus4 ,the object of the ,,journal ,,of ,,microscopy is to diffuse a knowledge of the best methods of using the ,microscope2 of all valuable improvements in the instrument and its accessories2 of all new methods of microscopical investigation1 and of the most recent results of microscopical research4 ,the ,,journal does not address itself to those who have long pursued certain special lines of research1 and whose wants can be supplied only by elaborate papers1 which1 from their thoroughness1 are entitled to be called monographs rather than mere articles4 ,it is intended rather to meet the wants of those who use the microscope for purposes of general study1 medical work1 class instruction1 and even amusement1 and who desire1 in addition to the information afforded by text-books1 such a knowledge of what others are doing as can be derived only from a periodical4 ,with this object in view1 therefore1 the publishers propose to make the ,,journal so simple1 practical and trustworthy1 that it will prove to the advantage of every one who uses the microscope at all to take it4 ,,illustrations4--,the ,,journal will be freely illustrated by engravings representing either objects of natural history or apparatus connected with the microscope4 ,,transactions ,,of ,,societies4--,,the ,,american ,,journal ,,of ,,microscopy is not the organ of any ,society1 but it gives the proceedings of all ,societies whose officers send us a report4 ,as the ,,journal is devoted wholly to ,microscopy1 and is in good form and size for binding1 no better medium can be had for preserving the scientific records of any society4 ,matters of mere business routine we are frequently obliged to omit for want of room4 ,,exchanges4--,an important feature of the ,,journal is the exchange column1 by means of which workers in different parts of the country are enabled1 without expense1 except for postage1 to exchange slides and materials with each other4 ,,terms4 ,during the first two years of its existence1 the subscription to the ,,american ,,journal ,,of ,,microscopy was only fifty cents per year1 but at the request of more than two-thirds of the subscribers1 the size of the ,,journal has been doubled1 and the price raised to ,,one ,,dollar ,,per ,,year4 ,four copies for three dollars4 ,those who wish to economize in the direction of periodicals1 would do well to examine our clubbing list4 ,,foreign ,,subscribers4--,the ,,journal will be sent1 postage paid1 to any country in the ,postal ,union for #a4bd1 or #e shillings sterling per year4 ,english postage stamps1 ,american currency or ,american postage stamps taken in payment4 ,in return for a postal order or draft for #a #es41 five copies of the ,,journal will be furnished and mailed to different addresses4 ,make all drafts and postal orders payable to ,john ,phin4 ,,back ,,volumes4--,we have on hand a few copies of ,vols4 ,i and ,,ii1 bound in handsome cloth cases1 which we offer for #a #be each4 ,vols4 ,i and ,,ii1 bound1 and the numbers of ,vol4 ,,iii1 as issued1 we offer for #b4ej4 ,we can no longer supply complete sets of #ahgf-g in sheets4 ,to those who wish to examine the journal1 we will send ten odd numbers for #be cents4 ,advertisements4 ,the ,,journal ,,of ,,microscopy1 from its very nature1 is a visitor to the very best families1 and its value as an advertising medium has therefore proved to be much above that of average periodicals4 ,a few select advertisements will be inserted at the rate of #cj cents per line1 nonpariel measure1 of which twelve lines make an inch4 ,address ,,american ,,journal ,,of ,,microscopy1 ,p4 ,o4 ,box #dhge1 ,new ,york4 ---------------------------------------- -------------------------------- ,transcriber's ,notes3 ,missing or obscured punctuation was corrected4 ,typographical errors were silently corrected4 ,inconsistent spelling was made consistent when a predominant form was found in this book2 otherwise it was not changed4 ,forms of the name ,schfer were regularized to match the title page of his 8,a ,course of ,practical ,histology40 ,text that was in italics is enclosed by underscores 7italics72 text that was bold by 8equal0 signs 7bold74