,transcriber's notes3 ,minor punctuation errors have been corrected silently 7e4g4 missing full stops after abbreviated words such as ,fig71 as have the following misspellings3 ,bretahing ,breathing1 ,pedicillaria ,pedicellaria1 ,pedicelaria ,pedicellaria1 ,chtonotus ,chtonotus1 ,spurganium ,sparganium1 veiw view4 ,unorthodox spelling and inconsistent hyphenation has not been altered4 ,several wrongly numbered cross-references to ,plates and ,figures have been corrected4 ,plate ,,viii 7and its accompanying key7 was originally displayed at the beginning of the book1 before the ,title ,page1 but has been repositioned in the body of the text in correct numerical sequence4 ,,common ,,objects ,,of ,,the ,,microscope ,,by ,,the ,,late ,rev4 ,j4 ,g4 ,,wood1 ,m4,a41 ,f4,l4,s41 ,etc4 ,,author ,,of 8,,common ,,objects ,,of ,,the ,,country0 8,,common ,,objects ,,of ,,the ,,sea-,,shore0 8,,my ,,feathered ,,friends0 ,,etc4 ,,etc4 ,,with ,,illustrations ,,by ,,tuffen ,,west ,,second ,,edition1 ,,revised ,,and ,,re-,,written1 ,,by ,e4 ,c4 ,,bousfield1 ,l4,r4,c4,p47,lond47 ,,author ,,of 8,a ,,guide ,,to ,,the ,,science ,,of ,,photo-,,micrography0 ,,with ,,additional ,,illustrations ,,by ,,the ,,reviser ,,london ,,george ,,routledge ,,and ,,sons1 ,limited ,,broadway ,,house1 ,,ludgate ,,hill #aijj ,,preface ,,to ,,the ,,second ,,edition ,the task of revising and bringing up to date a work which has been the guide1 philosopher1 and friend of thousands of commencing microscopists has been1 in the present case1 one of no small difficulty4 ,on the one hand1 there was the natural desire to interfere as little as possible with the original work2 and on the other1 the necessity of rendering available1 to some extent at least1 the enormous advance in every department which has taken place in the thirty-six years which have elapsed since the work was first offered to the public4 ,the reviser has done his best not only to fulfil these two objects1 but to keep in view the original purpose of the book4 ,in the popular department of pond-life especially1 about fifty new illustrations have been added1 mostly from the reviser's own notebook sketches4 ,the whole of the botanical part has been revised by one of our first ,english authorities1 and1 in short1 no effort has been spared to make the work as accurate as its necessarily condensed form permits of4 ,it is hoped1 therefore1 that it may be found not less useful than its predecessor by those for whom it is alone intended4 ,,preface ,,to ,,the ,,first ,,edition ,in my two previous handbooks1 the 8,common ,objects0 of the ,sea-shore and ,country1 ,i could but slightly glance at the minute beings which swarm in every locality1 or at the wonderful structures which are discovered by the ,microscope within or upon the creatures therein described4 ,since that time a general demand has arisen for an elementary handbook upon the ,microscope and its practical appliance to the study of nature1 and in order to supply that want this little volume has been produced4 ,i must warn the reader that he is not to expect a work that will figure and describe every object which may be found on the sea-shore or in the fields1 but merely one by which he will be enabled to guide himself in microscopical research1 and avoid the loss of time and patience which is almost invariably the lot of the novice in these interesting studies4 ,upwards of four hundred objects have been figured1 including many representatives of the animal1 vegetable1 and1 mineral kingdoms1 and among them the reader will find types sufficient for his early guidance4 ,neither must he expect that any drawings can fully render the lovely structures which are revealed by the microscope4 ,their form can be given faithfully enough1 and their colour can be indicated2 but no pen1 pencil1 or brush1 however skilfully wielded1 can reproduce the soft1 glowing radiance1 the delicate pearly translucency1 or the flashing effulgence of living and ever-changing light with which ,god wills to imbue even the smallest of ,his creatures1 whose very existence has been hidden for countless ages from the inquisitive research of man1 and whose wondrous beauty astonishes and delights the eye1 and fills the heart with awe and adoration4 ,owing to the many claims on my time1 ,i left the selection of the objects to ,mr4 ,tuffen ,west1 who employed the greater part of a year in collecting specimens for the express purpose1 and whose well-known fidelity and wide experience are the best guarantees that can be offered to the public4 ,to him ,i also owe many thanks for his kind revision of the proof-sheets4 ,my thanks are also due to ,messrs4 ,g4 and ,h4 ,brady1 who lent many beautiful objects1 and to ,messrs4 ,baker1 the well-known opticians of ,holborn1 who liberally placed their whole stock of slides and instruments at my disposal4 ,,contents ,,chapter ,i ,,page ,pleasures and ,uses of ,microscopy--,development of the ,microscope--,extemporised ,apparatus #a ,,chapter ,,ii ,elementary ,principles of ,optics--,simple ,microscopes--,compound ,microscope--,accessory ,apparatus--,cover-glasses--,troughs-- ,condensers--,dissection--,dipping-tubes --,drawing--,measurement #g ,,chapter ,,iii ,examination of ,objects--,principles of ,illumination--,mirror and its ,action--,substage ,condenser--,use of ,bull's-eye--,opaque ,objects--,photography of ,microscopic ,objects #bh ,,chapter ,,iv ,vegetable ,cells and their ,structure--,stellate ,tissues-- ,secondary ,deposit--,ducts and ,vessels--,wood-,cells--,stomata1 or ,mouths of ,plants--,the ,camera ,lucida1 and ,mode of ,using-- ,spiral and ,ringed ,vessels--,hairs of ,plants--,resins1 ,scents1 and ,oils--,bark ,cells #cg ,,chapter ,v ,starch1 its ,growth and ,properties--,surface ,cells of ,petals-- ,pollen and its ,functions--,seeds #fc ,,chapter ,,vi ,alg and their ,growth--,desmidiace1 where found--,diatoms1 their ,flinty ,deposit--,volvox--,mould1 ,blight1 and ,mildew-- ,mosses and ,ferns--,mare's-,tail and the ,spores--,common ,sea-weeds and their ,growth #gh ,,chapter ,,vii ,antenn1 their ,structure and ,use--,eyes1 ,compound and ,simple--,breathing ,organs--,jaws and their ,appendages--,legs1 ,feet1 and ,suckers--,digestive ,organs--,wings1 ,scales1 and ,hairs--,eggs of ,insects--,hair1 ,wool1 ,linen1 ,silk1 and ,cotton--,scales of ,fish--,feathers--,skin and its ,structure-- ,epithelium--,nails1 ,bone1 and ,teeth--,blood ,corpuscles and ,circulation--,elastic ,tissues--,muscle and ,nerve #if ,,chapter ,,viii ,pond-,life--,apparatus and ,instructions for ,collecting ,objects--,methods of ,examination--,sponge--,infusoria #acb ,,chapter ,,ix ,fresh-water ,worms--,planarians--,hydra--,polyzoa--, rotifers ,chtonotus--,water-,bears #add ,,chapter ,x ,marine ,life--,sponges--,infusoria--,foraminife ra--,radiolaria-- ,hydroid ,zoophytes--,polyzoa--,worms--,lingual ,ribbons and ,gills of ,mollusca--,star-,fishes and ,sea-,urchins--,cuttle-,fish-- ,corallines--,miscellaneous ,objects #aed ,,chapter ,,xi ,hints on the ,preparation of ,objects--,preservative ,fluids-- ,mounting ,media--,treatment of ,special ,objects #afh ,,chapter ,,xii ,section-,cutting--,staining #agi ,,common ,,objects ,,of ,,the ,,microscope ,,chapter ,i ,pleasures and ,uses of ,microscopy--,development of the ,microscope--,extemporised ,apparatus4 ,within the last half-century the use of the microscope1 not only as an instrument of scientific research1 a tool in the hands of the investigator of the finer organisation of the world of nature1 nor even as an adjunct to the apparatus of the chemist or the manufacturer1 but as a means of innocent and instructive recreation1 has become so firmly rooted amongst us that it seems hardly necessary to advocate its claims to attention on any of these grounds4 ,so wonderful is the information which it affords1 so indispensable is it in many1 if not in all1 branches of scientific research1 that not only would the lover of nature be deprived of one of his most valued sources of information and enjoyment1 but some sciences would be brought absolutely to a standstill if by any conceivable means the microscope were to be withdrawn from their followers4 ,on the other hand1 from every improvement in the construction of the latter1 a corresponding enlargement and enlightenment of the fields reviewed by these sciences has taken place1 and the beauty and interest of the revelations made by its means has attracted an ever-increasing host of earnest and intelligent volunteers1 who have rendered yeoman service to the cause of knowledge4 ,moreover1 so vast is the scope of the instrument1 that whilst discoveries in other fields of research are few and far between1 comparatively speaking1 in microscopic science they are of everyday occurrence1 and the number of problems calling for solution by means of the instrument in question is so vast that even the humblest worker may be of the greatest assistance4 ,in the following pages we propose to carry out1 as far as possible with reference to the microscope1 the system followed in the 8,common ,objects of the ,seashore and of the ,country10 and to treat in as simple a manner as may be of the marvellous structures which are found so profusely in our fields1 woods1 streams1 shores1 and gardens4 ,moreover1 our observations will be restricted to an instrument of such a class as to be inexpensively purchased and easily handled1 and to those pieces of supplementary apparatus which can be extemporised at small cost of money and ingenuity by the observer himself1 or obtained of the opticians for a few shillings4 ,with the same view1 the descriptions will be given in language as simple and as free from technicalities as possible1 though it must be remembered that for many of the organisms and structures which we shall have to describe there are none but scientific names2 and since1 moreover1 this little work is intended to furnish a stepping-stone between the very elements of microscopic science1 and those higher developments of it which should be the aim of every worker1 it would be unwise to attempt to invent commonplace appellations for the purpose of this book1 and leave him to discover1 when he came to consult works of reference in any particular subject1 that his 8simplified0 knowledge had all to be unlearnt1 and a new vocabulary acquired4 ,rather will it be our purpose to use correct terms1 and explain them1 as far as necessary1 as we introduce them4 ,the commencing microscopist is strongly recommended1 whilst not confining his interest entirely to one branch of research or observation1 to adopt some one as his particular province4 ,the opportunities for discovery and original work1 which are afforded by all alike1 will be more readily appreciated and utilised by adopting such a plan than by a general and purposeless distribution of effort4 ,to mention one or two4 ,the student of the fascinating field of pond-life will find new organisms awaiting description by the hundred1 and of the old ones1 life-histories to make out2 if he be attracted rather to the vegetable inhabitants of the same realm1 the diatoms will furnish him with the opportunity of studying1 and perhaps solving1 the enigma of their spontaneous movement1 and of watching their development4 ,the smaller fungi1 and indeed the larger ones too1 will amply repay the closest and most laborious study of their habits of life and processes of development4 ,since the first edition of this work was published1 the whole subject has been practically revolutionised1 and more remains to be done than has yet been accomplished4 ,in short1 there is scarcely an organism1 even of those best known and most studied1 which is so completely exhausted that persevering investigation would reveal nothing new concerning it4 ,there can be little doubt but that if any worker1 with moderate instrumental means1 but with an observant mind1 were to set determinately to work at the study of the commonest weed or the most familiar insect1 he1 or she1 would by patient labour accomplish work which would not only be of value to science1 but would redound to the credit of the worker4 ,something like finality appears to have been reached1 at least for the present1 in the development of the microscope2 and whilst it is beyond the scope of this work to treat of the refined and costly apparatus which is essential to useful work in certain departments of research1 the result has1 on the whole1 been highly favourable to the worker of moderate means and ambitions1 since lenses are now accessible1 at the cost of a few shillings1 comparatively speaking1 which could not have been purchased at all when this work first appeared4 ,it is with such appliances that we have here to deal4 ,the worker whose finances are restricted must be contented to extemporise for himself many pieces of apparatus1 and will find pleasure and occupation in doing so4 ,and let him remember1 for his encouragement1 that many such home-made appliances will fulfil their purpose quite as well as the imposing paraphernalia of glittering brass and glass which decorates the table of the wealthy amateur4 ,it is not the man who possesses the best or most costly apparatus1 but the one who best understands the use of that which he possesses1 that will make the most successful microscopist4 ,a good observer will discover1 with only the aid of a pocket-magnifier1 secrets of ,nature which have escaped the notice of a whole army of dilettante microscopists1 in spite of the advantages which1 as regards instruments1 the latter may enjoy4 ,it is for those who desire to be of the former class that this book is written1 and in the course of the following pages instances will be given in which the exercise of a small amount of ingenuity and the expenditure of a few pence will be found equivalent to the purchase of costly and complicated apparatus4 ,an enormous amount of valuable work was done in the earliest days of microscopy1 when the best apparatus available was a single lens1 composed of the bead formed by fusing the drawn-out end of a rod of glass4 ,inserted into a plate of metal1 or a piece of card1 such a primitive instrument was capable of affording a large amount of information4 ,similar instruments are to be purchased for a few pence at the present day1 and are not without their use for purposes of immediate examination of material4 ,a very common form is a glass marble1 ground flat on one side1 and mounted in a tube4 ,the material to be examined is placed upon the flat side1 and is seen magnified to an extent inversely proportional to the diameter of the sphere of glass4 ,,chapter ,,ii ,elementary ,principles of ,optics--,simple ,microscopes--,compound ,microscope--,accessory ,apparatus--,cover-glasses--,troughs-- ,condensers--,dissection--,dipping-tubes --,drawing--,measurement4 ,before proceeding to deal with the microscope itself1 it may be useful to give a short summary of the optical laws upon which its working depends4 ,to go into the minuti of the matter here would be out of place1 but it will be found very helpful1 especially in the matter of illumination1 to acquire some knowledge of1 and facility in applying1 these elementary principles4 ,we shall confine our remarks to convex lenses1 as being the form to which all the combinations in the microscope may be ultimately reduced4 ,every convex lens has one 8principal0 focus1 and an infinite number of 8conjugate0 foci4 ,the principal focus is the distance at which it brings together in one point the rays which fall upon it parallel to its axis1 as shown in ,fig4 #a1 in which ,a is the axis of the lens ,l1 and the rays ,,rr are brought together in the principal focus ,p4 ,thus a ready means of finding the focal length of any lens is to see at what distance it forms an image of the sun1 or of any other distant object1 upon a screen1 such as a piece of smooth white cardboard4 ,in the figure this distance will be ,,pl4 ,conversely1 if the source of light be at ,p1 a parallel beam of light will be emitted from the lens4 ,illustration3 ,fig4 #a4 ,the focal length may1 however1 be found in another way4 ,when an object is placed at a distance from a lens equal to twice the principal focal length of the latter1 an image of the object is formed at the same distance upon the other side of the lens1 inverted in position1 but of the same dimensions as the original object4 ,the object and image then occupy the equal conjugate foci of the lens1 so that by causing them to assume these relative positions1 and halving the distance at which either of them is from the lens1 the focal length of the latter is known4 ,these points will be seen on reference to ,fig4 #b1 in which ,l being the lens1 and ,p the principal focus1 as before1 rays from the point ,c are brought together at the conjugate focus ,c'1 at the same distance on the other side of ,l4 ,in this case it manifestly does not matter whether the object be at one or the other of these points4 ,illustration3 ,fig4 #b4 ,so far we have been dealing with points on the line of the axis of the lens4 ,the facts mentioned apply equally1 however1 to rays entering the lens at an angle to the axis1 only that in this case they diverge or converge1 correspondingly1 upon the other side4 ,it is evident1 from ,fig4 #a1 that no image is formed of a point situated at the distance of the principal focus2 but ,fig4 #c1 which is really an extension of ,fig4 #b1 shows how the rays passing along secondary axes form an inverted image of the same size as the object1 when the latter is situated at twice the focal length of the lens from this last4 ,to avoid confusion1 the bounding lines only are shown1 but similar lines might be drawn from each and every point of the object2 and if the lines ,,ala'1 ,,bl',b' be supposed to be balanced at ,l and ,l' respectively1 they will indicate the points at which the corresponding parts of the object and image will be situated along the lines ,,ab1 ,b',a' respectively4 ,moreover1 rays pass from every part of the object to every part of the lens1 so that we must imagine the cones ,,lal'1 ,,la',l' to be filled with rays diverging on one side of the lens and converging on the other4 ,the image so formed is a 8real0 image1--that is to say1 it can be thrown upon a screen4 ,illustration3 ,fig4 #c4 ,the microscopic image1 on the other hand1 is a virtual image1 which can be viewed by the eye but cannot be thus projected1 for it is formed by an object placed nearer to the lens than the principal focal length of the latter1 so that the rays diverge1 instead of converging1 as they leave the lens1 and the eye looks1 as it were1 back along the path in which the rays appear to travel1 and so sees an enlarged image situated in the air1 farther away than the object1 as shown in ,fig4 #d4 ,in this case1 as the diagram shows1 the image is upright1 not inverted4 ,images of the latter class are those formed by simple microscopes1 of the kind described in the previous chapter4 ,in the compound microscope the initial image1 formed by the object-glass1 is further magnified by another set of lenses1 forming the eye-piece1 by which the diverging rays of the virtual image are brought together to a focus at the eye-point2 and when viewed directly1 the eye sees an imaginary image1 as in a simple microscope1 whilst1 when the rays are allowed to fall upon a screen1 they form a real image of the object1 larger or smaller1 as the screen is farther from or nearer to the eye-point4 ,illustration3 ,fig4 #d4 ,these remarks must suffice for our present purpose4 ,those who are sufficiently interested in the subject to desire to know more of the delicate corrections to which these broad principles are subjected in practice1 that objectives may give images which are clear and free from colour1 to say nothing of other faults1 will do well to consult some such work as ,lommel's ,optics1 in the ,international ,science ,series4 ,in following a work such as the present one1 the simple microscope1 in some form or other1 will be found almost indispensable4 ,it will be required for examining raw material1 such as leaves or other parts of plants1 for gatherings of life in fresh or salt water1 for dissections4 ,with such powers as those with which we shall have to deal1 it will rarely happen that1 for example1 a bottle of water in which no life is visible will be worth the carrying-home2 whilst1 on the other hand1 a few months' practice will render it not only possible1 but easy1 not only to recognise the presence1 but to identify the genus1 and often even the species1 of the forms of life present4 ,moreover1 these low powers1 affording a general view of the object1 allow the relation to each other of the details revealed by the power of the compound microscope to be much more easily grasped4 ,a rough example may suffice to illustrate this4 ,a penny is a sufficiently evident object to the naked eye1 but it will require a sharp one to follow the details in ,britannia's shield1 whilst the minute scratches or the bloom upon the surface would be invisible in detail without optical aid4 ,conversely1 however1 it would be rash to conclude from an examination of a portion of the surface with the microscope alone that the portion in view was a sample of the whole surface4 ,the more the surface is magnified1 the less are the details grasped as a whole1 and for this reason the observer is strongly recommended to make out all that he can of an object with a simple magnifier before resorting to the microscope4 ,for general purposes1 the intending observer cannot do better than supply himself with a common pocket-magnifier1 with one1 two1 or three lenses1 preferably the last1 as although the absolute performance is not so accurate1 the very considerable range of power available by using the lenses singly1 or in various combinations1 is of great advantage4 ,such a magnifier may be obtained from ,baker for about three-and-sixpence1 or1 with the addition of a powerful ,coddington lens 7,fig4 #e7 in the same mount1 for nine shillings more4 ,aplanatic lenses1 such as the one shown in section in ,fig4 #f1 with a much flatter field of vision1 but of one power only each1 cost about fifteen shillings1 and a simple stand1 which adapts them for dissecting purposes1 may be obtained of the same maker for half a crown1 or may easily be extemporised from a cork sliding stiffly on an iron rod set in a heavy foot1 the cork carrying a loop of wire terminating in a ring which carries the lens4 ,illustration3 ,fig4 #e4 ,illustration3 ,fig4 #f4 ,so much may suffice for the simple microscope4 ,we pass on now to the consideration of the instrument which forms the subject of the present work1 an instrument which1 whilst moderate in price1 is yet capable of doing a large amount of useful and valuable work in the hands of a careful owner1 and of affording him a vast amount of pleasure and recreation1 even if these be his only objects in the purchase1 though it is difficult to understand that1 an insight being once attained into the revelations effected by the instrument1 without a desire being excited in any intelligent mind to pursue the subject as a study as well as a delightful relaxation4 ,the microscope described1 and adopted as his text by the author of this work1 is still made1 and has shared to a very considerable extent in the general improvement of optical apparatus which has taken place during the last thirty years4 ,it is to be obtained from ,baker1 #bdd ,high ,holborn1 and is provided with most of the apparatus which will be found indispensable by the beginner1 costing1 with a case in which to keep it1 the modest sum of three guineas4 ,illustration3 ,fig4 #g4 ,if this instrument represent the limit of the purchaser's power of purse1 he may very well make it answer his purpose for a considerable time4 ,the same instrument1 however1 with separate objectives of good quality1 together with a bull's-eye condenser 7an almost indispensable adjunct71 a plane mirror in addition to a concave one1 and a simple but efficient form of substage condenser1 may be obtained for #e1 #abs4 #f;d41 and the extra outlay will be well repaid by the advantage in working which is gained by the possession of the additional apparatus4 ,illustration3 ,fig4 #h4 ,a still better stand1 and one which is good enough for almost any class of work1 is that shown in ,fig4 #h1 which is known as the 8,portable0 microscope4 ,in this instrument the body is made up of two tubes1 so that the length may be varied at will1 and this gives a very considerable range of magnification without changing the object-glass1 a great convenience in practice2 whilst the legs fold up for convenience of carriage1 so that the whole instrument1 with all necessary appliances1 may be readily packed in a corner of a portmanteau for transport to the country or seaside4 ,the objectives supplied with the simplest form of microscope above referred to are combinations of three powers in one1 and the power is varied by using one1 two1 or three of these in combination4 ,this form of objective is very good1 as far as it goes1 though it is impossible to correct such a combination with the accuracy which is possible in manufacturing one of a fixed focal length4 ,perhaps the best thing for the beginner to do would be to purchase the combination first1 and1 later on1 to dispose of it and buy separate objectives of1 say1 one-inch1 half-inch1 and quarter-inch focal lengths4 ,it may be explained here1 that when a lens is spoken of as having a certain focal length1 it is meant that the magnification obtained by its use is the same1 at a distance of ten inches from the eye1 as would be obtained by using a simple sphere of glass of the same focal length at the same distance4 ,this1 of course1 is simply a matter of theory1 for such lenses are never used actually4 ,illustration3 ,fig4 #i4 ,of accessory apparatus1 we may mention first the stage forceps 7,fig4 #i1 a74 ,these are made to fit into a hole upon the stage1 so as to be capable of being turned about in any direction1 with an object in their grasp1 and for some purposes1 especially such as the examination of a thin object1 say the edge of a leaf1 they are extremely useful4 ,illustration3 ,fig4 #aj4 ,the live box1 in which drops of water or portions of water-plants1 or the like1 may be examined1 will be found of great service4 ,by adjustment of the cap upon the cylinder1 with proper attention to the thickness of the cover-glass in the cap1 any required amount of pressure1 from that merely sufficient to fix a restless object to an amount sufficient to crush a resistent tissue1 may easily be applied1 whilst the result of the operation is watched through the microscope4 ,this proceeding is greatly facilitated if the cap of the live-box be slotted spirally1 with a stud on the cylinder1 so that a half-turn of the cap brings the glasses into contact4 ,by this means the pressure may be adjusted with the greatest nicety4 ,in examining delicate objects1 such as large infusoria1 which invariably commit suicide when pressure is applied1 a good plan is to restrict their movements by placing a few threads of cotton-wool1 well pulled out1 in the live-box with the drop of water4 ,a variety of instruments has been invented for the same purpose1 of which ,beck's parallel compressorium may be mentioned as the most efficient1 though it is somewhat complicated1 and consequently expensive1 costing about twenty-five shillings4 ,a few glass slips and cover-glasses will also be required4 ,the latter had better be those known as 8,no4 #b10 since the beginner will find it almost impossible to clean the thinner ones satisfactorily without a large percentage of fractures4 ,the safest way is to boil the thin glass circles in dilute nitric acid 7half acid1 half water7 for a few minutes1 wash well in several waters1 first tap-water and then distilled1 and finally to place the covers in methylated spirit4 ,when required for use1 the spirit may be burnt off by applying a light1 the cover-glass1 held in a pair of forceps1 being in no way injured by the process4 ,in addition to the glass slides1 the observer will find it advisable to be provided with a few glass troughs1 of various thicknesses1 in which portions of water-plants1 having organisms attached to them1 may be examined4 ,confined in the live-box1 many of the organisms ordinarily found under such circumstances can rarely be induced to unfold their beauties1 whilst in the comparative freedom of the trough they do so readily4 ,the troughs may be purchased1 or may be made of any desired shape or size by cutting strips of glass of a thickness corresponding to the depth desired1 cementing these to a glass slide somewhat larger than the ordinary one1 and cementing over the frame so formed a piece of thin glass1 ,no4 #c2 the best material to use as cement being marine glue of the best quality1 or1 failing this1 ,prout's elastic glue1 which is much cheaper1 but also less satisfactory4 ,the glass surface must be made1 in either case1 sufficiently hot to ensure thorough adhesion of the cement1 as the use of any solvent entails long waiting1 and considerable risk of poisoning the organisms4 ,a useful practical hint in the use of these troughs is that the corners1 at the top1 should be greased slightly1 otherwise the water finds its way out by capillary attraction1 to the detriment of the stage of the microscope4 ,of optical accessories1 the bull's-eye is almost the most valuable4 ,so much may be effected by its means alone1 in practised hands1 that it is well worth the while of the beginner to master its use thoroughly1 and the methods of doing so will be explained in the succeeding chapter4 ,the substage condenser1 too1 even in its most simple form1 is an invaluable adjunct1 even though it be only a hemisphere of glass1 half an inch or so in diameter1 mounted in a rough sliding jacket to fit underneath the stage4 ,such an instrument1 properly fitted1 will cost about fifteen shillings1 but the ingenious worker will easily extemporise one for himself4 ,illustration3 ,fig4 #aa4 ,many plants and animals require to be dissected to a certain extent before the details of their structure can be made out1 and for this purpose the naked eye alone will rarely serve4 ,the ordinary pocket magnifier1 however1 if mounted as described in a preceding chapter1 will greatly facilitate matters1 and the light may be focused upon the object by means of the bull's-eye condenser1 as shown in ,fig4 #aa4 ,in the figure the latter is represented as used in conjunction with the lamp1 but daylight is preferable if it be available1 the strain upon the eyes being very much less than with artificial light4 ,two blocks of wood1 about four inches high1 will form convenient rests for the hands1 a plate of glass being placed upon the blocks to support the dish1 and a mirror being put in the interspace at an angle of #de or so if required4 ,a piece of black paper may be laid upon the mirror if reflected light alone is to be used4 ,as all delicate structures are dissected under fluid1 a shallow dish is required4 ,for this purpose nothing is better than one of the dishes used for developing photographic negatives4 ,the bottom of the dish is occupied by a flat cork1 to which a piece of flat lead is attached below1 and the object having been pinned on to the cork in the required position1 the fluid is carefully run in4 ,this fluid will naturally vary according to the results desired to be obtained1 but it must not be plain water1 which so alters all cellular structures as to practically make them unrecognisable under the microscope4 ,nothing could be better than a #e per cent4 solution of formalin1 were it not for the somewhat irritating odour of this fluid1 since it at once fixes the cells and preserves the figure4 ,for many purposes a solution of salt1 in the proportion of a saltspoonful of the latter to a pint of water1 will answer well for short dissections4 ,for more prolonged ones1 a mixture of spirit-and-water1 one part of the former to two of the latter1 answers well1 especially for vegetable structures4 ,when the dilution is first made1 the fluid becomes milky1 unless pure spirit be used1 but with a little trouble the ,revenue authorities may be induced to give permission for the use of pure methylated spirit1 which answers every purpose4 ,the trouble then is that not less than five gallons can be purchased1 an embarras de richesses for the average microscopist1 but1 after all1 the spirit is extremely cheap1 and does not deteriorate by keeping4 ,when the dissection in either of these media is completed1 spirit should be gradually added to bring the strength up to #ej per cent41 in which the preparation may remain for a day or two1 after which it is gradually brought into pure spirit1 or into water again1 according to the medium in which it is to be mounted4 ,illustration3 ,fig4 #ab4 ,as to the tools required1 they are neither numerous nor expensive4 ,fine-pointed but strong forceps 7,fig4 #i1 c71 curved and straight2 a couple of pairs of scissors1 one strong and straight1 the other more delicate1 and having curved blades1 and a few needles of various thicknesses and curves1 are the chief ones4 ,the latter may be made by inserting ordinary needles1 for three-fourths of their length1 into sticks of straight-grained deal 7ordinary firewood answers best71 and thereafter bending them as required4 ,a better plan1 however1 is to be provided with a few of the needle-holders shown in ,fig4 #i1 b4 ,these are very simple and inexpensive1 and in them broken needles are readily replaced by others4 ,dipping-tubes1 such as are shown in ,fig4 #ab1 will also be extremely useful for many purposes4 ,these are very easily made by heating the centre of a piece of soft glass tubing of the required size1 and1 when it is quite red-hot1 drawing the ends apart4 ,the fine tube in the centre should now be divided by scratching it with a fine triangular file1 and the scratch may of course be made at such a point as to afford a tube of the required fineness4 ,the edges should be smoothed by holding them in the flame until they just run 7not melt1 or the tube will close74 ,these tubes can often be made to supply the place of a glass syringe4 ,they may be used either for sucking up fluid or for transferring it1 placing the finger over the wide end1 allowing the tube to fill by displacement of air1 and then re-closing it with the finger4 ,this last method is especially useful for transferring small objects from one receptacle to another4 ,in speaking of the dissection of objects1 it should have been mentioned that the microscope itself may1 under careful handling1 be made to serve very well1 only1 as the image is reversed1 it is almost impossible to work without using a prism to re-erect the image4 ,such a prism is shown in ,fig4 #ac4 ,the microscope is placed vertically1 and the observer1 looking straight into the prism1 sees all the parts of the image in their natural positions4 ,this appliance is extremely useful for the purpose of selecting small objects1 and arranging them on slides in any desired manner4 ,a few words may be added as to the reproduction of the images of objects4 ,illustration3 ,fig4 #ac4 ,the beginner is strongly recommended to practise himself in this from the outset4 ,even a rough sketch is worth pages of description1 especially if the magnification used be appended2 and even though the worker may be devoid of artistic talent1 he will find that with practice he will acquire a very considerable amount of facility in giving truthful outlines at least of the objects which he views4 ,various aids have been devised for the purpose of assisting in the process4 ,the simplest and cheapest of these consists of a cork cut so as to fit round the eye-piece4 ,into the cork are stuck two pins1 at an angle of #de to the plane of the cork1 and1 the microscope being placed horizontally1 a thin cover-glass is placed upon the two pins1 the light being arranged and the object focused after the microscope is inclined4 ,on looking vertically down upon the cover-glass1 a bright spot of light will be seen1 and as the eye is brought down into close proximity with it the spot will expand and allow the observer to see the whole of the image without looking into the microscope4 ,if a sheet of paper be now placed upon the table at the place occupied by the image so projected1 the whole of the details will be clearly seen1 as will also the point of a pencil placed upon the paper in the centre of the field of view2 and1 after a little practice1 it will be found easy to trace round the chief details of the object4 ,two points require attention4 ,the first is that if the light upon the paper be stronger than that in the apparent field of the microscope1 the image will not be well seen1 or if the paper be too feebly lighted1 it will be difficult to keep the point of the pencil in view4 ,the light from the microscope is thrown into the eye1 and the view of the image upon the paper is the effect of a mental act1 the eye looking out in the direction from which the rays appear to come4 ,the paper has therefore to be illuminated independently1 and half the battle lies in the adjustment of the relative brightness of image and paper4 ,the second point is1 that it is essential to fix one particular point in the image as the starting-point of the drawing1 and this being first depicted1 the image and drawing of this point must be kept always coincident1 or the drawing will be distorted1 since the smallest movement of the eye alters the relations of the whole4 ,the reflector must be placed at an angle of #de1 or the field will be oval instead of circular4 ,the simple form of apparatus just described has one drawback1 inasmuch as the reflection is double1 the front and back of the cover-glass both acting as reflectors4 ,the image from the latter being much the more feeble of the two1 care in illumination will do much to eliminate this difficulty2 but there are various other forms in which the defect in question is got rid of4 ,the present writer has worked with all of them1 from the simple neutral tint reflector of ,beale to the elaborate and costly apparatus of ,zeiss1 and1 upon the whole1 thinks that he prefers the cover-glass to them all4 ,a very simple plan1 not so mechanical as the last-named1 consists in the use of 8drawing-squares10 which are delicate lines ruled upon a piece of thin glass1 and dropped into the eye-piece so that the lines rest upon the diaphragm of the eye-piece1 and therefore are in focus at the same time as the object4 ,by the use of these1 in combination with paper similarly ruled1 a diagram of any required size can be drawn with very great facility4 ,the squares1 if compared with a micrometer1 will furnish an exact standard of magnitude for each object-glass employed4 ,the micrometer is a piece of thin glass upon which are ruled minute divisions of an inch or a millimeter4 ,suppose the micrometer to be placed under the microscope when the squares are in the eye-piece1 and it be found that each division corresponds with one square of the latter1 then1 if the micrometric division be one one-hundredth of an inch1 and the squares upon the paper measure one inch1 it is clear that the drawing will represent the object magnified a hundred 8diameters02 if two divisions of the micrometer correspond to three squares1 the amplification will be a hundred and fifty diameters2 if three divisions correspond to two squares1 sixty-six diameters1 and so on4 ,if a draw-tube be used1 it will be necessary to know the value of the squares at each inch of the length1 if they are to be used for measuring magnification4 ,,chapter ,,iii ,examination of ,objects--,principles of ,illumination--,mirror and its ,action--,substage ,condenser--,use of ,bull's-eye--,opaque ,objects--,photography of ,microscopic ,objects4 ,so much depends upon a right method of employing the microscope1 as regards both comfort and accuracy1 that we propose to devote a little space to the consideration of the subject4 ,let us first warn the intending observer against the use of powers higher than are required to bring out the details of the object4 ,mere magnification is of very little use3 it increases the difficulties both of illumination and of manipulation1 and1 as already said1 interferes with that grasp of the object which it is most desirable to obtain4 ,rather let the beginner lay himself out to get the very most he can out of his lowest powers1 and he will find that1 by so doing1 he will be able far better to avail himself of the higher ones when their use is indispensable4 ,the essential means to this end is a mastery of the principles of illumination1 which we now proceed to describe4 ,we suppose the microscope to be inclined at an angle of about #gj to the horizontal1 with a low-power objective attached to it1 a one-inch by preference4 ,opposite to the microscope1 and about a foot away from it1 is a lamp with the edge of the flame presented to the microscope1 the concave mirror of which is so arranged as to receive the rays from the flame and direct them up the tube of the microscope4 ,upon the stage is placed a piece of ground-glass1 and the mirror-arm is now to be moved up or down upon its support until the ground-glass receives the maximum of illumination1 which it will do when the lamp-flame is at one conjugate focus of the mirror and the ground-glass at the other4 ,the focus will not be an image of the flame1 but a bar of light4 ,if an object be now placed upon the stage1 instead of the ground-glass1 and the objective focused upon it1 it will1 if the mirror be properly adjusted1 be brilliantly illuminated4 ,it will be understood that every concave mirror has a focus1 and converges the rays which fall upon it to this focus1 behaving exactly like a convex lens4 ,the principal focus of a concave mirror is its radius of curvature1 and this is not difficult to determine4 ,place side by side a deep cardboard box and the lamp1 so that the concave mirror may send the rays back1 along a path only slightly inclined to that by which they reached it1 to the bottom of the box4 ,the lamp and box being equidistant from the mirror1 it is evident that when the mirror forms an image of the former upon the latter equal to the flame in size1 we have the equivalent of the equal conjugate foci shown in ,fig4 #b4 ,now move the box to the distance from the mirror which corresponds to the distance of the stage of the microscope from the mirror when the latter is in position upon the microscope1 and then move the lamp to or fro until the mirror casts a sharp image of the flame upon the bottom of the box1 which is not to be moved4 ,the lamp distance so found will be the correct one for working with the concave mirror4 ,the writer is led to lay special stress upon this matter1 from the fact that he almost invariably finds that the mirror is arranged to be used for parallel rays1 i4e4 for daylight1 and is therefore fixed far too close to the stage to be available for correct or advantageous working with the lamp1 unless1 indeed1 the bull's-eye condenser be used1 as hereinafter described1 to parallelise the rays from the lamp4 ,work done with the concave mirror can1 however1 under the most favourable conditions1 only be looked upon as a pis aller4 ,the advantages gained by the use of some substage condenser1 even the most simple1 in conjunction with the plane mirror1 or even without any mirror at all1 are so manifold that the beginner is strongly urged to provide himself with some form or other of it1 and we now proceed to describe the way in which this should be used to produce the best effect4 ,to reduce the problem to its most simple elements1 turn the mirror altogether out of the way1 and place the microscope upon a block at such a height as shall be convenient for observation1 and shall allow the rays from the lamp1 placed in a line with it on the table1 to shine directly into the tube of the microscope4 ,ascertain that this is so by removing both objective and eye-piece and looking down the tube1 when the flame should be seen in the centre1 edgewise4 ,now replace the eye-piece1 and screw on to the tube the one-inch combination or objective4 ,place upon the stage an object1 preferably a round diatom or an echinus-spine1 and focus it as sharply as possible4 ,now place the substage condenser in its jacket1 and slide it up and down until the image of the object is bisected by the image of the flame4 ,the centre of the object will now be brilliantly illuminated by rays travelling in the proper direction for yielding the best results4 ,the object is situated at the common focus of the microscope and the condenser1 and1 whatever means of illumination be adopted1 this is the result which should always be aimed at4 ,satisfactory as this critical arrangement is1 however1 from a scientific point of view1 it has its drawbacks from an artistic and sthetic one4 ,it is not pleasant1 for most purposes1 to have merely the centre of an object lighted up1 and we have now to consider how the image of the edge of the flame may be so expanded as to fill the field without sacrificing more than a very small fraction of the accuracy of the arrangement just attained4 ,referring to ,fig4 #a1 we see that if we place the lamp at the principal focus of a lens1 it will emit a bundle of parallel rays equal in diameter to the diameter of the lens4 ,this is the key of the position4 ,we cannot place the lamp at an infinite distance from the substage condenser1 but we can supply the latter with rays approximately parallel1 so that it shall bring them to a focus upon the object at very nearly its own principal focus4 ,this we do by means of the bull's-eye condenser4 ,place the latter1 with its flat side toward the edge of the flame1 and at its principal focal distance 7the method of determining which has already been described7 from the latter1 so that the bundle of parallel rays which issue from it may pass up to the substage condenser4 ,on examining the object again1 it will be found that1 after slight adjustments of the position of the bull's-eye have been made1 the object lies in the centre of an evenly and brilliantly lighted field4 ,it may be necessary to place the bull's-eye a little farther from or nearer to the lamp1 or to move it a little to one side or the other1 but when it is at the correct distance1 and on the central line between the lamp and the substage condenser1 at right angles to this line1 the effects will be as described4 ,it may help in securing this result if we mention that when the bull's-eye is too far from the lamp1 the image of the flame is a spindle-shaped one2 whilst1 when the distance between the two is too short1 i4e4 less than the principal focal length of the lens1 the field is crossed by a bar or light1 the ends of which are joined by a ring1 whilst on either side of the bar there is a semi-circular dark space4 ,we have hitherto supposed the objects viewed to be transparent1 but there are many1 of great interest1 which are opaque1 and call for other means of illumination4 ,of these there are several4 ,the simplest and1 in many ways1 the best is to use the bull's-eye condenser to bring to a focus upon the object the rays of light from some source placed above the stage of the microscope4 ,if light can be obtained from the sun itself1 no lens will be needed to concentrate it2 and indeed1 if this were done1 there would be considerable risk of burning the object4 ,the light from a white cloud1 however1 with the help of the bull's-eye1 answers admirably4 ,at night-time an artificial source of light1 the more intense and the more distant the better1 is required4 ,for most cases1 and with powers not higher than one inch1 a good paraffin lamp1 placed about two feet away from the stage1 and on one side of it1 so as to be about a foot above the level of the object1 will give all that is needed4 ,such a lamp is shown in ,fig4 #ad4 ,low magnifications are1 as a rule1 all that is called for in this method4 ,lieberkuhn's condensers are useful aids1 but are somewhat expensive4 ,they are concave mirrors1 which are so adjusted to the objective that the latter and the reflector come into focus together1 the light being sent in from below1 or from one side4 ,one other method of illumination must be mentioned before leaving the topic1 and this is the illumination of objects upon a 8dark field40 ,with suitable subjects1 and when carefully managed1 there is no method which gives more beautiful effects1 and it has the great advantage of allowing the object to be brilliantly lighted1 without the strain to the eyes which is involved in such lighting by the usual method of direct illumination4 ,illustration3 ,fig4 #ad4 ,it consists essentially in allowing the light to fall upon the object from below1 at such an angle that none of it can enter the objective directly4 ,thus the concave mirror1 turned as far as possible to one side1 and reflecting on to the object the rays from the lamp placed upon the opposite side1 will give very fair results with low powers2 this plan1 however1 is capable of but very limited application4 ,again1 a disc of black paper may be stuck on to the middle of the bull's-eye1 and the latter be placed below the stage between it and the mirror4 ,in this case everything depends upon the size of the disc1 which1 if too small1 will not give a black ground1 and if too large will cut off all light from the object4 ,the best and only really satisfactory plan is to arrange the illumination with the substage condenser1 as previously described1 and then to place below the lens of the latter a central stop of a suitable size1 which can only be determined by trial4 ,when this has been done the object will be seen brilliantly illuminated upon a field of velvety blackness4 ,such stops are supplied with the condenser4 ,we have devoted a considerable portion of space to this question1 since it is1 of all others1 the most important to a successful1 satisfactory1 and reliable manipulation of the microscope2 but even now1 only the main points of the subject have been touched upon1 and the worker will find it necessary to supplement the information given by actual experiment4 ,a few failures1 rightly considered1 will afford a great amount of information1 but those who desire to go thoroughly into the matter are recommended to consult the present writer's ,guide to the ,science of ,photomicrography1 where it is treated at much greater length1 as an essential part of the subject-matter of the book4 ,it may be added here1 that no method of reproducing the images of objects is on the whole so satisfactory as the photographic one2 and whilst a lengthened reference to the topic would be out of place in a work of the character of the present one1 the one just mentioned will be found to contain all that is necessary to enable the beginner to produce results which1 for faithfulness and beauty1 far excel any drawing1 whilst they have the additional advantage that they can1 if required1 be exhibited to hundreds simultaneously4 ,,chapter ,,iv ,vegetable ,cells and their ,structure--,stellate ,tissues--,secondary ,deposit--,ducts and ,vessels--,wood-,cells--,stomata1 or ,mouths of ,plants--,the ,camera ,lucida1 and ,mode of ,using--,spiral and ,ringed ,vessels--,hairs of ,plants--,resins1 ,scents1 and ,oils--,bark ,cells4 ,we will now suppose the young observer to have obtained a microscope and learned the use of its various parts1 and will proceed to work with it4 ,as with one or two exceptions1 which are only given for the purpose of further illustrating some curious structure1 the whole of the objects figured in this work can be obtained without any difficulty1 the best plan will be for the reader to procure the plants1 insects1 etc41 from which the objects are taken1 and follow the book with the microscope at hand4 ,it is by far the best mode of obtaining a systematic knowledge of the matter1 as the quantity of objects which can be placed under a microscope is so vast that1 without some guide1 the tyro flounders hopelessly in the sea of unknown mysteries1 and often becomes so bewildered that he gives up the study in despair of ever gaining any true knowledge of it4 ,i would therefore recommend the reader to work out the subjects which are here mentioned1 and then to launch out for himself on the voyage of discovery4 ,i speak from experience1 having myself known the difficulties under which a young and inexperienced observer has to labour in so wide a field1 without any guide to help him to set about his work in a systematic manner4 ,the objects that can be most easily obtained are those of a vegetable nature1 as even in ,london there is not a square1 an old wall1 a greenhouse1 a florist's window1 or even a greengrocer's shop1 that will not afford an exhaustless supply of microscopic employment4 ,even the humble vegetables that make their daily appearance on the dinner-table are highly interesting2 and in a crumb of potato1 a morsel of greens1 or a fragment of carrot1 the enthusiastic observer will find occupation for many hours4 ,following the best examples1 we will commence at the beginning1 and see how the vegetable structure is built up of tiny particles1 technically called 8cells40 ,that the various portions of every vegetable should be referred to the simple cell is a matter of some surprise to one who has had no opportunity of examining the vegetable structure1 and indeed it does seem more than remarkable that the tough1 coarse bark1 the hard wood1 the soft pith1 the green leaves1 the delicate flowers1 the almost invisible hairs1 and the pulpy fruit1 should all start from the same point1 and owe their origin to the simple vegetable cell4 ,this1 however1 is the case2 and by means of a few objects chosen from different portions of the vegetable kingdom1 we shall obtain some definite idea of this curious phenomenon4 ,i4 ,,fig4 #a4 ,strawberry1 cellular tissue #b4 ,buttercup leaf1 internal layer #c4 ,privet1 ,seed ,coat1 showing star-shaped cells #d4 ,rush1 ,star-shaped cells #e4 ,mistletoe1 cells with ringed fibre #f4 ,cells from interior of ,lilac bud #g4 ,bur-reed 7,sparganium71 square cells from leaf #h4 ,six-sided cells1 from stem of ,lily #i4 ,angular dotted cells1 rind of ,gourd #aj4 ,elongated ringed cells1 anther of ,narcissus #aa4 ,irregular star-like tissue1 pith of ,bulrush #ab4 ,six-sided cells1 pith of elder #ac4 ,young cells from ,wheat #ad4 ,do4 rootlets of ,wheat #ae4 ,wood-cells1 ,elder #af4 ,glandular markings and resin1 8,cedar0 pencil #ag4 ,do4 ,yew #ah4 ,scalariform tissue1 ,stalk of ,fern #ai4 ,dotted ,duct1 ,willow #bj4 ,do4 ,stalk of ,wheat #ba4 ,wood-cell1 ,chrysanthemum #bb4 ,do4 ,lime-tree #bc4 ,dotted ,duct1 ,carrot #bd4 ,cone-bearing wood1 ,deal #be4 ,cells1 outer coat1 ,gourd #bf4 ,ducts1 ,elm #bg4 ,cellular tissue1 ,stalk of ,chickweed #bh4 ,holly-berry1 outer coat ,illustration3 ,i4 ,on ,plate ,i4 ,fig4 #a1 may be seen three cells of a somewhat globular form1 taken from the common strawberry4 ,any one wishing to examine these cells for himself may readily do so by cutting a very thin slice from the fruit1 putting it on a slide1 covering it with a piece of thin glass 7which may be cheaply bought at the optician's1 together with the glass slides on which the objects are laid71 and placing it under a power of two hundred diameters4 ,should the slice be rather too thick1 it may be placed in the live-box and well squeezed1 when the cells will exhibit their forms very distinctly4 ,in their primary form the cells seem to be spherical2 but as in many cases they are pressed together1 and in others are formed simply by the process of subdivision1 the spherical form is not very often seen4 ,the strawberry1 being a soft and pulpy fruit1 permits the cells to assume a tolerably regular form1 and they consequently are more or less globular4 ,where the cells are of nearly equal size1 and are subjected to equal pressure in every direction1 they force each other into twelve-sided figures1 having the appearance under the microscope of flat six-sided forms4 ,fig4 #h1 in the same ,plate1 taken from the stem of a lily1 is a good example of this form of cell1 and many others may be found in various familiar objects4 ,we must here pause for a moment to define a cell before we proceed further4 ,the cell is a close sac or bag formed of a substance called from its function 8cellulose10 and containing certain semi-fluid contents as long as it retains its life4 ,in the interior of the cell may generally be found a little dark spot1 termed the 8ncleus10 and which may be seen in ,fig4 #a1 to which we have already referred4 ,the object of the nucleus is rather a bone of contention among the learned1 but the best authorities on this subject consider it to be the vital centre of the cells1 to and from which tends the circulation of the protoplasm1 and which is intimately connected with the growth and reproduction of the cell4 ,on looking a little more closely at the nucleus1 we shall find it marked with several small light spots1 which are termed 8nucloli40 ,on the same ,plate 7,fig4 #b7 is a pretty group of cells taken from the internal layer of the buttercup leaf1 and chosen because they exhibit the series of tiny and brilliant green dots to which the colour of the leaf is due4 ,the technical name for this substance is 8chlorophyll10 or 8leaf-green10 and it may always be found thus dotted in the leaves of different plants1 the dots being very variable in size1 number1 and arrangement4 ,a very fine object for the exhibition of this point is the leaf of ,ancharis1 the 8,canadian timber-weed10 to be found in almost every brook and river4 ,it also shows admirably the circulation of the protoplasm in the cell4 ,in the centre of the same ,plate 7,fig4 #ab7 is a group of cells from the pith of the elder-tree4 ,this specimen is notable for the number of little 8pits0 which may be seen scattered across the walls of the cells1 and which resemble holes when placed under the microscope4 ,in order to test the truth of this appearance1 the specimen was coloured blue by the action of iodine and dilute sulphuric acid1 when it was found that the blue tint spread over the pits as well as the cell-walls1 showing that the membrane is continuous over the pits4 ,fig4 #g exhibits another form of cell1 taken from the ,spargnium1 or bur-reed4 ,these cells are tolerably equal in size1 and have assumed a square shape4 ,they are obtained from the lower part of the leaf4 ,the reader who has any knowledge of entomology will not fail to observe the similarity in form between the six-sided and square cells of plants and the hexagonal and square facets of the compound eyes of insects and crustaceans4 ,in a future page these will be separately described4 ,sometimes the cells take most singular and unexpected shapes1 several examples of which will be briefly noticed4 ,in certain loosely made tissues1 such as are found in the rushes and similar plants1 the walls of the cells grow very irregularly1 so that they push out a number of arms which meet each other in every direction1 and assume the peculiar form which is termed 8stellate10 or star-shaped tissue4 ,fig4 #c shows a specimen of stellate tissue taken from the seed-coat of the privet1 and rather deeply coloured1 exhibiting clearly the beautiful manner in which the arms of the various stars meet each other4 ,a smaller group of stellate cells taken from the stem of a large rush1 and exemplifying the peculiarities of the structure1 are seen in ,fig4 #d4 ,the reader will at once see that this mode of formation leaves a vast number of interstices1 and gives great strength with little expenditure of material4 ,in water-plants1 such as the reeds1 this property is extremely valuable1 as they must be greatly lighter than the water in which they live1 and at the same time must be endowed with considerable strength in order to resist its pressure4 ,a less marked example of stellate tissue is given in ,fig4 #aa1 where the cells are extremely irregular1 in their form1 and do not coalesce throughout4 ,this specimen is taken from the pithy part of a bulrush4 ,there are very many other plants from which the stellate cells may be obtained1 among which the orange affords very good examples1 in the so-called 8white0 that lies under the yellow rind1 a section of which may be made with a very sharp razor1 and placed in the field of the microscope4 ,looking toward the bottom of the ,plate1 and referring to ,fig4 #bg1 the reader will observe a series of nine elongated cells1 placed end to end1 and dotted profusely with chlorophyll4 ,these are obtained from the stalk of the common chickweed4 ,another example of the elongated cell is seen in ,fig4 #ad1 which is a magnified representation of the rootlets of wheat4 ,here the cells will be seen set end to end1 and each containing its nucleus4 ,on the left hand of the rootlet 7,fig4 #ac7 is a group of cells taken from the lowest part of the stem of a wheat plant which had been watered with a solution of carmine1 and had taken up a considerable amount of the colouring substance4 ,many experiments on this subject were made by the ,rev4 ,lord ,s4 ,g4 ,osborne1 and may be seen at full length in the pages of the ,microscopical ,journal1 the subject being too large to receive proper treatment in the very limited space which can here be given to it4 ,it must be added that later researches have caused the results here described to be gravely disputed4 ,fig4 #i on the same ,plate exhibits two notable peculiarities--the irregularity of the cells and the copiously pitted deposit with which they are covered4 ,the irregularity of the cells is mostly produced by the way in which the multiplication takes place1 namely1 by division of the original cell into two or more new ones1 so that each of these takes the shape which it assumed when a component part of the parent cell4 ,in this case the cells are necessarily very irregular1 and when they are compressed from all sides they form solid figures of many sides1 which1 when cut through1 present a flat surface marked with a variety of irregular outlines4 ,this specimen is taken from the rind of a gourd4 ,the 8pitted0 structure which is so well shown in this figure is caused by a layer of matter which is deposited in the cell and thickens its walls1 and which is perforated with a number of very minute holes called 8pits40 ,this substance is called 8secondary deposit40 ,that these pits do not extend through the real cell-wall has already been shown in ,fig4 #ab4 ,this secondary deposit assumes various forms4 ,in some cases it is deposited in rings round the cell1 and is clearly placed there for the purpose of strengthening the general structure4 ,such an example may be found in the mistletoe 7,fig4 #e71 where the secondary deposit has formed itself into clear and bold rings that evidently give considerable strength to the delicate walls which they support4 ,fig4 #aj shows another good instance of similar structure2 differing from the preceding specimen in being much longer and containing a greater number of rings4 ,this object is taken from an anther of the narcissus4 ,among the many plants from which similar objects may be obtained1 the yew is perhaps one of the most prolific1 as ringed wood-cells are abundant in its formation1 and probably aid greatly in giving to the wood the strength and elasticity which have long made it so valuable in the manufacture of bows4 ,before taking leave of the cells and their remarkable forms1 we will just notice one example which has been drawn in ,fig4 #f4 ,this is a congeries of cells1 containing their nuclei1 starting originally end to end1 but swelling and dividing at the top4 ,this is a very young group of cells 7a young hair1 in fact7 from the inner part of a lilac bud1 and is here introduced for the purpose of showing the great similarity of all vegetable cells in their earliest stages of existence4 ,having now examined the principal forms of cells1 we arrive at the 8vessels10 a term which is applied to those long and delicate tubes which are formed of a number of cells set end to end1 their walls of separation being absorbed4 ,in ,fig4 #ai the reader will find a curious example of the 8pitted vessel10 so called from the multitude of little markings which cover its walls1 and are arranged in a spiral order4 ,like the pits and rings already mentioned1 the dots are composed of secondary deposit in the interior of the tube1 and vary very greatly in number1 function1 and dimensions4 ,this example is taken from the wood of the willow1 and is remarkable for the extreme closeness with which the dots are packed together4 ,immediately on the right hand of the preceding figure may be seen another example of a dotted vessel 7,fig4 #bj71 taken from a wheat stem4 ,in this instance the cells are not nearly so long1 but are wider than in the preceding example1 and are marked in much the same way with a spiral series of dots4 ,about the middle of the topmost cell is shown the short branch by which it communicates with the neighbouring vessel4 ,fig4 #bc exhibits a vessel taken from the common carrot1 in which the secondary deposit is placed in such a manner as to resemble a net of irregular meshes wrapped tightly round the vessel4 ,for this reason it is termed a 8netted vessel40 ,a very curious instance of these structures is given in ,fig4 #bf1 at the bottom of the ,plate1 where are represented two small vessels from the wood of the elm4 ,one of them--that on the left hand--is wholly marked with spiral deposit1 the turns being complete2 while1 in the other instance1 the spiral is comparatively imperfect1 and the cell-walls are marked with pits4 ,if the reader would like to examine these structures more attentively1 he will find plenty of them in many familiar garden vegetables1 such as the common radish1 which is very prolific in these interesting portions of vegetable nature4 ,there is another remarkable form in which this secondary deposit is sometimes arranged that is well worthy of our notice4 ,an example of this structure is given in ,fig4 #ah1 taken from the stalk of the common fern or brake4 ,it is also found in very great perfection in the vine4 ,on inspecting the illustration1 the reader will observe that the deposit is arranged in successive bars or steps1 like those of a winding staircase4 ,in allusion to the ladder-like appearance of this formation1 it is called 8scalariform0 7,latin1 scala1 a ladder74 ,in the wood of the yew1 to which allusion has already been made1 there is a very peculiar structure1 a series of pits found only in those trees that bear cones1 and therefore termed the coniferous pitted structure4 ,fig4 #af is a section of a common cedar pencil1 the wood1 however1 not being that of the true cedar1 but of a species of fragrant ,juniper4 ,this specimen shows the peculiar formation which has just been mentioned4 ,any piece of deal or pine will exhibit the same peculiarities in a very marked manner1 as is seen in ,fig4 #bd4 ,a specimen may be readily obtained by making a very thin shaving with a sharp plane4 ,in this example the deposit has taken a partially spiral form1 and the numerous circular pits with which it is marked are only in single rows4 ,in several other specimens of coniferous woods1 such as the ,araucaria1 or ,norfolk ,island pine1 there are two or three rows of pits4 ,a peculiarly elegant example of this spiral deposit may be seen in the wood of the common yew 7,fig4 #ag74 ,if an exceedingly thin section of this wood be made1 the very remarkable appearance will be shown which is exhibited in the illustration4 ,the deposit has not only assumed the perfectly spiral form1 but there are two complete spirals1 arranged at some little distance from each other1 and producing a very pretty effect when seen through a good lens4 ,the pointed1 elongated shape of the wood-cells is very well shown in the common elder-tree 7see ,fig4 #ae74 ,in this instance the cells are without markings1 but in general they are dotted like ,fig4 #ba1 an example cut from the woody part of the chrysanthemum stalk4 ,this affords a very good instance of the wood-cell1 as its length is considerable1 and both ends are perfect in shape4 ,on the right hand of the figure is a drawing of the wood-cell found in the lime-tree 7,fig4 #bb71 remarkable for the extremely delicate spiral markings with which it is adorned4 ,in these wood-cells the secondary deposit is so plentiful that the original membranous character of the cell-walls is entirely lost1 and they become elongated and nearly solid cases1 having but a very small cavity in their centre4 ,it is to this deposit that the hardness of wood is owing1 and the reader will easily see the reason why the old wood is so much harder than the young and new shoots4 ,in order to permit the passage of the fluids which maintain the life of the part1 it is needful that the cell-wall be left thin and permeable in certain places1 and this object is attained either by the 8pits0 described on page a href,page#dcdc_/;a1 or by the intervals between the spiral deposit4 ,at the right-hand bottom corner of ,plate ,i4 7,fig4 #bh7 may be seen a prettily marked object1 which is of some interest4 ,it is a slice stripped from the outer coat of the holly-berry1 and is given for the purpose of illustrating the method by which plants are enabled to breathe the atmospheric air on which they depend as much as ourselves1 though their respiration is slower4 ,among the mass of net-like cells may be seen three curious objects1 bearing a rather close resemblance to split kidneys4 ,these are the mouths1 or 8stmata10 as they are scientifically called4 ,in the centre of the mouths may be seen a dark spot1 which is the aperture through which the air communicates with the passages between the cells in the interior of the structure4 ,in the flowering plants their shape is generally rounded1 though they sometimes take a squared form1 and they regularly occur at the meeting of several surface cells4 ,the two kidney-shaped cells which form the 8mouth0 are the 8guard-cells10 so called from their function1 since1 by their change of form1 they cause the mouth to open or shut1 according to the needs of the plant4 ,in young plants these guard-cells are very little below the surface of the leaf or skin1 but in others they are sunk quite beneath the layer of cells forming the outer coat of the tissue4 ,there are other cases where they are slightly elevated above the surface4 ,stomata are found chiefly in the green portions of plants1 and are most plentiful on the under side of leaves4 ,it is1 however1 worthy of notice1 that when an aquatic leaf floats on the water1 the mouths are only to be found on the upper surface4 ,these curious and interesting objects are to be seen in many structures where we should hardly think of looking for them2 for instance1 they may be found existing on the delicate skin which envelops the kernel of the common walnut4 ,as might be expected1 their dimensions vary with the character of the leaf on which they exist1 being large upon the soft and pulpy leaves1 and smaller upon those of a hard and leathery consistence4 ,the reader will find ample amusement1 and will gain great practical knowledge of the subject1 by taking a plant1 say a tuft of groundsel1 and stripping off portions of the external skin or 8epidermis0 from the leaf or stem1 etc41 so as to note the different sizes and shapes of the stomata4 ,on the opposite bottom corner of ,plate ,i4 ,fig4 #be1 is an example of a stoma taken from the outer skin of a gourd1 and here given for the purpose of showing the curious manner in which the cells are arranged about the mouth1 no less than seven cells being placed round the single mouth1 and the others arranged in a partially circular form around them4 ,turning to ,plate ,,ii41 we find several other examples of stomata1 the first of which 7,fig4 #a7 is obtained from the under surface of the buttercup leaf1 by stripping off the external skin1 or 8epidermis10 as it is scientifically termed4 ,the reader will here notice the slightly waved outlines of the cell-walls1 together with the abundant spots of chlorophyll with which the leaf is coloured4 ,in this example the stomata appear open4 ,their closure or expansion depends chiefly on the state of the weather2 and1 as a general rule1 they are open by day and closed at night4 ,a remarkably pretty example of stomata and elongated cells is to be obtained from the leaf of the common iris1 and may be prepared for the microscope by simply tearing off a strip of the epidermis from the under side of the leaf1 laying it on a slide1 putting a little water on it1 and covering it with a piece of thin glass4 7,see ,plate ,,ii4 ,fig4 #b47 ,there are a number of longitudinal bands running along the leaf where these cells and stomata appear4 ,the latter are not placed at regular intervals1 for it often happens that the whole field of the microscope will be filled with cells without a single stoma1 whilst elsewhere a group of three or four may be seen clustered closely together4 ,fig4 #c on the same ,plate exhibits a specimen of the beautifully waved cells1 without mouths1 which are found on the upper surface of the ivy leaf4 ,these are difficult to arrange from the fresh leaf1 but are easily shown by steeping the leaf in water for some time1 and then tearing away the cuticle4 ,the same process may be adopted with many leaves and cuticles1 and in some cases the immersion must be continued for many days1 and the process of decomposition aided by a very little nitric acid in the water1 or by boiling4 ,on the same ,plate are three examples of spiral and ringed vessels1 types of an endless variety of these beautiful and interesting structures4 ,fig4 #d is a specimen of a spiral vessel taken from the lily1 and is a beautiful example of a double spire4 ,the deposit which forms this spiral is very strong1 and it is to the vast number of these vessels that the stalk owes its well-known elasticity4 ,in many cases the spiral vessels are sufficiently strong to be visible to the naked eye1 and to bear uncoiling4 ,for example1 if a leaf-stalk of geranium be broken across1 and the two fragments gently drawn asunder1 a great number of threads1 drawn from the spiral vessels1 will be seen connecting the broken ends4 ,in this case the delicate membranous walls of the vessel are torn apart1 and the stronger fibre which is coiled spirally within it unrolls itself in proportion to the force employed4 ,in many cases these fibres are so strong that they will sustain the weight of an inch or so of the stalk4 ,in ,fig4 #e is seen a still more bold and complex form of this curious structure2 being a coil of five threads1 laid closely against each other1 and forming1 while remaining in their natural position1 an almost continuous tube4 ,this specimen is taken from the root of the water lily1 and requires some little care to exhibit its structure properly4 ,every student of nature must be greatly struck with the analogies between different portions of the visible creation4 ,these spiral structures which we have just examined are almost identical in appearance1 and to some extent in their function1 with the threads that are coiled within the breathing tubes of insects4 ,this is in both cases twofold1 namely1 to give support and elasticity to a delicate membrane1 and to preserve the tube in its proper form1 despite the bending to which it may be subjected4 ,when we come to the anatomy of the insect in a future page we shall see this structure further exemplified4 ,in some cases the deposit1 instead of forming a spiral coil1 is arranged in a series of rings1 and the vessel is then termed 8annulated40 ,a very good example of this formation is given in ,fig4 #f1 which is a sketch of such a vessel1 taken from a stalk of the common rhubarb4 ,to see these ringed vessels properly1 the simplest plan is to boil the rhubarb until it is quite soft1 then to break down the pulpy mass until it is flattened1 to take some of the most promising portions with the forceps1 lay them on the slide and press them down with a thin glass cover4 ,they will not be found scattered at random through the fibres1 which elsewhere present only a congeries of elongated cells1 but are seen grouped together in bundles1 and with a little trouble may be well isolated1 and the pulpy mass worked away so as to show them in their full beauty4 ,as may be seen in the illustration1 the number of the rings and their arrangement is extremely variable4 ,a better1 but somewhat more troublesome1 plan is to cut longitudinal sections of the stem1 as described in our concluding chapter1 when not only the various forms of cells and vessels1 but their relations to each other1 will be well shown4 ,the numerous crystals of oxalate of lime1 which make rhubarb so injurious a food for certain persons1 will also be well seen4 ,these crystals are called 8raphides10 and are to be found in very many plants in different forms4 ,,ii4 ,,fig4 #a4 ,cuticle1 ,buttercup leaf #b4 ,do4 ,iris #c4 ,do4 ,ivy leaf #d4 ,spiral vessel1 ,lily #e4 ,do4 root1 7rhizome7 ,water ,lily #f4 ,ringed vessel1 ,rhubarb #g4 ,chaff1 after burning #h4 ,bifid hair1 ,arabis #i4 ,hair1 ,marvel of ,peru #aj4 ,end of hair1 leaf of ,hollyhock #aa4 ,hair1 ,sowthistle leaf #ab4 ,do4 ,tobacco #ac4 ,do4 ,southernwood #ad4 ,group of hairs1 ,hollyhock leaf #ae4 ,hair1 ,yellow ,snapdragon #af4 ,do4 ,moneywort #ag4 ,hair1 ,geum #ah4 ,do4 ,flower of ,heartsease #ai4 ,do4 ,dockleaf #bj4 ,do4 ,throat of ,pansy #ba4 ,do4 ,dead-nettle ,flower #bb4 ,do4 ,groundsel #bc4 ,cell1 ,beech-nut #bd4 ,do4 ,pine cone #be4 ,vitta1 ,caraway ,seed #bf4 ,cork #bg4 ,hair1 ,flower of ,garden ,verbena #bh4 ,do4 fruit of ,plane #bi4 ,do4 do4 #cj4 ,do4 do4 #ca4 ,do4 ,lobelia #cb4 ,do4 ,cabbage #cc4 ,do4 ,dead-nettle flower #cd4 ,do4 ,garden ,verbena flower #ce4 ,fruit-hair1 ,dandelion #cf4 ,hair1 ,thistle leaf #cg4 ,do4 ,cactus #ch4 ,do4 do4 #ci4 ,do4 ,virginian ,spider-wort #dj4 ,do4 ,lavender #da4 ,section1 ,lavender leaf1 ,hairs and perfume-gland #db4 ,section1 ,orange ,peel #dc4 ,sting of ,nettle #dd4 ,hair1 ,marigold flower #de4 ,do4 ,ivy ,illustration3 ,,ii4 99 99 99 99 99 ,the hairs of plants form very interesting objects1 and are instructive to the student1 as they afford valuable indications of the mode in which plants grow4 ,they are all appendages of and arise from the skin or epidermis2 and although their simplest form is that of a projecting and elongated cell1 the variety of shapes which are assumed by these organs is inexhaustible4 ,on ,plate ,,ii4 are examples of some of the more striking forms1 which will be briefly described4 ,the simple hair is well shown in ,figs4 #ah1 #ai1 and #cb1 the first being from the flower of the heartsease1 the second from a dock-leaf1 and the third from a cabbage4 ,in ,fig4 #ah the hair is seen to be but a single projecting cell1 consisting only of a wall and the contents4 ,in ,fig4 #ai the hair has become more decided in shape1 having assumed a somewhat dome-like form2 and in ,fig4 #cb it has become considerably elongated1 and may at once be recognised as a true hair4 ,in ,fig4 #h is a curious example of a hair taken from the white ,arabis1 one of the cruciferous flowers1 which is remarkable for the manner in which it divides into two branches1 each spreading in opposite directions4 ,another example of a forked hair is seen in ,fig4 #ac1 but in this instance the hair is composed of a chain of cells1 the three lower forming the stem of the hair1 and the two upper being lengthened into the lateral branches4 ,this hair is taken from the common southernwood4 ,in most cases of long hairs1 the peculiar elongation is formed by a chain of cells1 varying greatly in length and development4 ,several examples of these hairs will be seen on the same ,plate4 ,fig4 #i is a beaded hair from the ,marvel of ,peru1 which is composed of a number of separate cells placed end to end1 and connected by slender threads in a manner that strongly reminds the observer of a chain of beads strung loosely together1 so as to show the thread by which they are connected with each other4 ,another good example is seen at ,fig4 #aa1 in a hair taken from the leaf of the sowthistle4 ,in this case the beads are strung closely together1 and when placed under a rather high power of the microscope have a beautifully white and pearly aspect4 ,the leaf must be dry and quite fresh1 and the hairs seen against the green of the leaf4 ,fig4 #ci represents another beaded hair taken from the ,virginian ,spiderwort1 or ,tradescantia4 ,this hair is found upon the stamens1 and is remarkable for the beautifully beaded outline1 the fine colouring1 and the spiral markings with which each cell is adorned4 ,a still further modification of these many-celled hairs is found in several plants1 where the hairs are formed by a row of ordinarily shaped cells1 with the exception of the topmost cell1 which is suddenly elongated into a whip-like form4 ,fig4 #bb represents a hair of this kind1 taken from the common groundsel2 and ,fig4 #cf is a still more curious instance1 found upon the leaf of the thistle4 ,the reader may have noticed the peculiar white 8fluffy0 appearance of the thistle leaf when it is wet after a shower of rain4 ,this appearance is produced by the long lash-like ends of the hairs1 which are bent down by the weight of the moisture1 and lie almost at right angles with the thicker portions of the hair4 ,an interesting form of hair is seen in the 8sting0 of the common nettle4 ,this may readily be examined by holding a leaf edgewise in the stage forceps1 and laying it under the field of the microscope4 ,in order to get the proper focus throughout the hair1 the finger should be kept upon the screw movement1 and the hair brought gradually into focus from its top to its base4 ,the general structure of this hair is not unlike that which characterises the fang of a venomous serpent4 ,the acrid fluid which causes the pain is situated in the enlarged base of the hair1 and is forced through the long straight tubular extremity by means of the pressure exerted when the sting enters the skin4 ,at the very extremity of the perfect sting is a slight bulb-like swelling1 which serves to confine the acrid juice1 and which is broken off on the least pressure4 ,the sting is seen in ,fig4 #dc4 ,the extremities of many hairs present very curious forms1 some being long and slender1 as in the examples already mentioned1 while others are tipped with knobs1 bulbs1 clubs1 or rosettes in endless variety4 ,fig4 #ab is a hair of the tobacco leaf1 exhibiting the two-celled gland at the tip1 containing the peculiar principle of the plant1 known by the name of 8nicotine40 ,the reader will see how easy it is to detect adulteration of tobacco by means of the microscope4 ,the leaves most generally used for this purpose are the dock and the cabbage1 so that if a very little portion of leaf be examined the character of the hairs will at once inform the observer whether he is looking at the real article or its substitute4 ,fig4 #ae is a hair from the flower of the common yellow snapdragon1 which is remarkable for the peculiar shape of the enlarged extremity1 and for the spiral markings with which it is decorated4 ,fig4 #af is a curious little knobbed hair found upon the moneywort1 and ,fig4 #ag is an example of a double-knobbed hair taken from the ,geum4 ,fig4 #cd affords a very curious instance of a glandular hair1 the stem being built up of cells disposed in a very peculiar fashion1 and the extremity being developed into a beautiful rosette-shaped head4 ,this hair came from the ,garden ,verbena4 ,curiously branched hairs are not at all uncommon1 and some very good and easily obtained examples are given on ,plate ,,ii4 ,fig4 #bh is one of the multitude of branched hairs that surround the well-known fruit of the plane-tree1 the branches being formed by some of the cells pointing outward4 ,these hairs do not assume precisely the same shape2 for ,fig4 #bi exhibits another hair from the same locality1 on which the spikes are differently arranged1 and ,fig4 #cj is a sketch of another such hair1 where the branches have become so numerous and so well developed that they are quite as conspicuous as the parent stem4 ,one of the most curious and interesting forms of hair is that which is found upon the lavender leaf1 and which gives it the peculiar bloom-like appearance on the surface4 ,this hair is represented in ,figs4 #dj and #da4 ,on ,fig4 #dj the hair is shown as it appears when looking directly upon the leaf1 and in ,fig4 #da a section of the leaf is given1 showing the mode in which the hairs grow into an upright stem1 and then throw out horizontal branches in every direction4 ,between the two upright hairs1 and sheltered under their branches1 may be seen a glandular appendage not unlike that which is shown in ,fig4 #af4 ,this is the reservoir containing the perfume1 and it is evidently placed under the spreading branches for the benefit of their shelter4 ,on looking upon the leaf by reflected light the hairs are beautifully shown1 extending their arms on all sides2 and the globular perfume cells may be seen scattered plentifully about1 gleaming like pearls through the hair-branches under which they repose4 ,they will be found more numerous on the under side of the leaf4 ,this object will serve to answer a question which the reader has probably put to himself ere this1 namely1 ,where are the fragrant resins1 scents1 and oils stored8 ,on ,plate ,i4 ,fig4 #af1 will be seen the reply to the first question2 ,fig4 #da of the present ,plate has answered the second question1 and ,fig4 #db will answer the third4 ,this figure represents a section of the rind of an orange1 the flattened cells above constituting the delicate yellow skin1 and the great spherical object in the centre being the reservoir in which the fragrant essential oil is stored4 ,the covering is so delicate that it is easily broken1 so that even by handling an orange some of the scent is sure to come off on the hands1 and when the peel is stripped off and bent double1 the reservoirs burst in myriads1 and fling their contents to a wonderful distance4 ,this may be easily seen by squeezing a piece of orange peel opposite a lighted candle1 and noting the distance over which the oil will pass before reaching the flame1 and bursting into little flashes of light4 ,other examples are given on the same plate4 ,returning to the barbed hairs1 we may see in ,fig4 #ce a highly magnified view of the 8pappus0 hair of a dandelion1 i4e4 the hairs which fringe the arms of the parachute-like appendage which is attached to the seed4 ,the whole apparatus will be seen more fully on ,plate ,,iii4 ,figs4 #dd1 #de1 #df4 ,this hair is composed of a double layer of elongated cells lying closely against each other1 and having the ends of each cell jutting out from the original line4 ,a simpler form of a double-celled1 or more properly a 8duplex0 hair1 will be seen in ,fig4 #dd4 ,this is one of the hairs from the flower of the marigold and has none of the projecting ends to the cells4 ,in some instances the cell-walls of the hairs become greatly hardened by secondary deposit1 and the hairs are then known as spines4 ,two examples of these are seen in ,figs4 #cg and #ch1 the former being picked from the ,indian fig-cactus1 and well known to those persons who have been foolish enough to handle the fig roughly before feeling it4 ,the wounds which these spines will inflict are said to be very painful1 and have been compared to those produced by the sting of the wasp4 ,the latter hair is taken from the ,opuntia4 ,these spines must not be confounded with thorns2 which latter are modified branches4 ,fig4 #aj represents the extreme tip of a hair from the hollyhock leaf1 subjected to a lens of very high power4 ,many hairs assume a star-like appearance1 an aspect which may be produced in different ways4 ,sometimes a number of simple hairs start from the same base1 and by radiating in different directions produce the stellate effect4 ,an example of this kind of hair may be seen in ,fig4 #ad1 which is a group of hairs from the hollyhock leaf4 ,there is another mode of producing the star-shape which may be seen in ,fig4 #de1 a hair taken from the leaf of the ivy4 ,very fine examples may also be found upon the leaf of ,deutzia scabra4 ,hairs are often covered with curious little branches or protuberances1 and present many other peculiarities of form which throw a considerable light upon certain problems in scientific microscopy4 ,fig4 #cc represents a hair of two cells taken from the flower of the well-known dead-nettle1 which is remarkable for the number of knobs scattered over its surface4 ,a similar mode of marking is seen in ,fig4 #ca1 a club-shaped hair covered with external projections1 found in the flower of the ,lobelia4 ,in order to exhibit these markings well1 a power of two hundred diameters is needed4 ,fig4 #ba shows this dotting in another hair from the dead-nettle1 where the cell is drawn out to a great length1 but is still covered with these markings4 ,fig4 #bj is an example of a very curious hair taken from the throat of the pansy4 ,this hair may readily be obtained by pulling out one of the petals1 when the hairs will be seen at its base4 ,under the microscope it has a particularly beautiful appearance1 looking just like a glass walking-stick covered with knobs1 not unlike those huge1 knobby club-like sticks in which some farmers delight1 where the projections have been formed by the pressure of a honeysuckle or other climbing plant4 ,a hair of a similar character1 but even more curious1 is found in the same part of the flower of the ,garden ,verbena 7see ,fig4 #bg71 and is not only beautifully translucent1 but is coloured according to the tint of the flower from which it is taken4 ,its whole length is covered with large projections1 the joints much resembling the antenn of certain insects2 and each projection is profusely spotted with little dots1 formed by elevation of the outer skin or cuticle4 ,these are of some value in determining the structure of certain appearances upon petals and other portions of the flowers1 and may be compared with ,figs4 #cc to #ce on ,plate ,,iii4 ,fig4 #bf offers an example of the square cells which usually form the bark of trees4 ,this is a transverse section of cork1 and perfectly exhibits the form of bark cells4 ,the reader is very strongly advised to cut a delicate section of the bark of various trees1 a matter very easily accomplished with the aid of a sharp razor and a steady hand4 ,fig4 #bd is a transverse section through one of the scales of a pine-cone1 and is here given for the purpose of showing the numerous resin-filled cells which it displays4 ,this may be compared with ,fig4 #af of ,plate ,i4 ,fig4 #be is a part of one of the 8vitt10 or oil reservoirs1 from the fruit of the caraway1 showing the cells containing the globules of caraway oil4 ,this is rather a curious object1 because the specimen from which it was taken was boiled in nitric acid1 and yet retained some of the oil globules4 ,immediately above it may be seen 7,fig4 #bc7 a transverse section of the beechnut1 showing a cell with its layers of secondary deposit4 ,in the cuticle of the grasses and the mare's-tails is deposited a large amount of pure flint4 ,so plentiful is this substance1 and so equally is it distributed1 that it can be separated by heat or acids from the vegetable parts of the plant1 and will still preserve the form of the original cuticle1 with its cell-walls1 stomata1 and hairs perfectly well defined4 ,fig4 #g1 ,plate ,,ii41 represents a piece of wheat chaff1 or 8bran10 that has been kept at a white heat for some time1 and then mounted in ,canada balsam4 ,i prepared the specimen from which the drawing was made by laying the chaff on a piece of platinum1 and holding it over the spirit-lamp4 ,a good example of the silex or flint in wheat is often given by the remains of a straw fire1 where the stems may be seen still retaining their tubular form but fused together into a hard glassy mass4 ,it is this substance that cuts the fingers of those who handle the wild grasses too roughly1 the edges of the blades being serrated with flinty teeth1 just like the obsidian swords of the ancient ,mexicans1 or the shark's-tooth falchion of the ,new ,zealander4 ,these are but short and meagre accounts of a very few objects1 but space will not permit of further elucidation1 and the purpose of this little work is not to exhaust the subjects of which it treats1 but to incite the reader to undertake investigation on his own account1 and to make his task easier than if he had done it unaided4 ,,chapter ,v ,starch1 its ,growth and ,properties--,surface ,cells of ,petals--,pollen and its ,functions--,seeds4 ,the white substance so dear to the laundries under the name of starch is found in a vast variety of plants1 being distributed more widely than most of the products which are found in the interior of vegetable cells4 ,the starch grains are of very variable size even in the same plant1 and their form is as variable as their size1 though there is a general resemblance in those of the same plant which allows of their being fairly easily identified after a moderate amount of practice4 ,sometimes the grains are found loosely packed in the interior of the cells1 and are then easily recognised as starch grains by their peculiar form and the delicate lines with which they are marked2 but in many places they are pressed so closely together that they assume an hexagonal shape under the microscope1 and bear a close resemblance to ordinary twelve-sided cells4 ,in other plants1 again1 the grains never advance beyond the very minute form in which they seem to commence their existence2 and in some1 such as the common oat1 a great number of very little granules are compacted together so as to resemble one large grain4 ,there are several methods of detecting starch in those cases where its presence is doubtful2 and the two modes that are usually employed are polarised light and the iodide of potassium4 ,when polarised light is employed--a subject on which we shall have something to say presently--the starch grains assume the characteristic 8black-cross10 and when a plate of selenite is placed immediately beneath the slide containing the starch grains1 they glow with all the colours of the rainbow4 ,the second plan is to treat them with a very weak solution of iodine and iodide of potassium1 and in this case the iodine has the effect on the starch granules of staining them blue4 ,they are so susceptible of this reaction that when the liquid is too strong the grains actually become black from the amount of iodine which they imbibe4 ,nothing is easier than to procure starch granules in the highest perfection4 ,take a raw potato1 and with a razor cut a very thin slice from its interior1 the direction of the cut not being of the slightest importance4 ,put this delicate slice upon a slide1 drop a little water upon it1 cover it with a piece of thin glass1 give it a good squeeze1 and place it under a power of a hundred or a hundred and fifty diameters4 ,any part of the slice1 provided that it be very thin1 will then present the appearance shown in ,plate ,,iii4 ,fig4 #i1 where an ordinary cell of potato is seen filled loosely with starch grains of different sizes4 ,around the edges of the slice a vast number of starch granules will be seen1 which have been squeezed out of their cells by pressure1 and are now floating freely in the water4 ,as cold water has no perceptible effect upon starch1 the grains are not altered in form by the moisture1 and can be examined at leisure4 ,,iii4 ,,fig4 #a4 ,laurel leaf1 transverse section #b4 ,starch1 ,wheat #c4 ,do4 from ,pudding #d4 ,do4 ,potato #e4 ,outer ,skin1 ,capsicum pod #f4 ,starch1 ,parsnip #g4 ,do4 ,arrow ,root1 ,west ,indian #h4 ,do4 8,tousles ,mois0 #i4 ,do4 in cell of ,potato #aj4 ,do4 ,indian ,corn #aa4 ,do4 ,sago #ab4 ,do4 ,tapioca #ac4 ,root1 ,yellow ,water-,lily #ad4 ,starch1 ,rice #ae4 ,do4 ,horsebean #af4 ,do4 ,oat #ag4 ,pollen1 ,snowdrop #ah4 ,do4 ,wallflower #ai4 ,do4 ,willow ,herb1 a pollen tube #bj4 ,do4 ,violet #ba4 ,do4 ,musk ,plant #bb4 ,do4 ,apple #bc4 ,do4 ,dandelion #bd4 ,do4 ,sowthistle #be4 ,do4 ,lily #bf4 ,do4 ,heath #bg4 ,do4 ,heath1 another species #bh4 ,pollen1 ,furze #bi4 ,do4 ,tulip #cj4 ,petal1 ,pelargonium #ca4 ,do4 ,periwinkle #cb4 ,do4 ,golden ,balsam #cc4 ,do4 ,snapdragon #cd4 ,do4 ,primrose #ce4 ,do4 ,scarlet ,geranium #cf4 ,pollen1 ,crocus #cg4 ,do4 ,hollyhock #ch4 ,fruit1 ,galium1 ,goosegrass #ci4 ,a hook of ditto more magnified #dj4 ,seed1 ,red ,valerian #da4 ,portion of ,parachute of same1 more magnified #db4 ,seed1 ,foxglove #dc4 ,do4 ,sunspurge #dd4 ,parachute1 ,dandelion seed #de4 ,seed1 ,dandelion #df4 ,do4 ,hair of ,parachute #dg4 ,do4 ,yellow ,snapdragon #dh4 ,do4 ,mullein #di4 ,do4 ,robin ,hood #ej4 ,do4 ,bur-reed #ea4 ,do4 ,willow ,herb #eb4 ,do4 ,musk ,mallow ,illustration3 ,,iii4 ,on focusing with great care1 the surface of each granule will be seen to be covered with very minute dark lines1 arranged in a manner which can be readily comprehended from ,fig4 #d1 which represents two granules of potato starch as they appear when removed from the cell in which they took their origin4 ,all the lines evidently refer to the little dark spots at the end of the granule1 called technically the 8hilum10 and represent the limits of successive layers of material deposited one after another4 ,the lines in question are very much better seen if the substage condenser be used with a small central stop1 so as to obtain partial dark-field illumination4 ,otherwise they are often very difficult of detection4 ,in the earliest stages of their growth the starch granules appear to be destitute of these markings1 or at all events they are so few and so delicate as not to be visible even with the most perfect instruments1 and it is not until the granules assume a comparatively large size that the external markings become distinctly perceptible4 ,we will now glance at the examples of starch which are given in the ,plate1 and which are a very few out of the many that might be figured4 ,fig4 #b represents the starch of wheat1 the upper grain being seen in front1 the one immediately below it in profile1 and the two others being examples of smaller grains4 ,fig4 #f is a specimen of a very minute form of starch1 where the granules do not seem to advance beyond their earliest stage4 ,this specimen is obtained from the parsnip2 and although the magnifying power is very great1 the dimensions of the granules are exceedingly small1 and except by a very practised eye they would not be recognisable as starch grains4 ,fig4 #c is a good example of a starch grain of wheat1 exemplifying the change that takes place by the combined effects of heat and moisture4 ,it has already been observed that cold water exercises little1 if any1 perceptible influence upon starch2 but it will be seen from the illustration that hot water has a very powerful effect4 ,when subjected to the action of water at a temperature over #adj ,fahr41 the granule swells rapidly1 and at last bursts1 the contents escaping in a gelatinous mass1 and the external membrane collapsing into the form which is shown in ,fig4 #c1 which was taken out of a piece of hot pudding4 ,a similar form of wheat starch may also be detected in bread1 accompanied1 unfortunately1 by several other substances not generally presumed to be component parts of the 8staff of life40 ,in ,fig4 #g are represented some grains of starch from ,west ,indian arrowroot1 and ,fig4 #h exhibits the largest kind of starch grain known1 obtained from the tuber of a species of canna1 supposed to be ,c4 edlis1 a plant similar in characteristics to the arrowroot4 ,the popular name of this starch is 8,tous les ,mois10 and under that title it may be obtained from the opticians1 or chemists4 ,fig4 #aj shows the starch granules from ,indian corn1 as they appear before they are compressed into the honeycomb-like structure which has already been mentioned4 ,even in that state1 however1 if they are treated with iodine1 they exhibit the characteristics of starch in a very perfect manner4 ,fig4 #aa is starch from sago1 and ,fig4 #ab from tapioca1 and in both these instances the several grains have been injured by the heat employed in preparing the respective substances for the market4 ,fig4 #ac exhibits the granules obtained from the root of the water-lily1 and ,fig4 #ad is a good example of the manner in which the starch granules of rice are pressed together so as to alter the shape and puzzle a novice4 ,fig4 #af is the compound granule of the oat1 which has already been mentioned1 together with some of the simple granules separated from the mass2 and ,fig4 #ae is an example of the starch grains obtained from the underground stem of the horse-bean4 ,it is worthy of mention that the close adhesion of the rice starch into those masses is the cause of the peculiar grittiness which distinguishes rice flour to the touch4 ,whilst very easily acted on by heat1 starch-granules are very resistent to certain other reagents4 ,weak alkalies1 in watery solution1 readily attack them1 but by treating portions of plants with caustic potash dissolved in strong spirit1 the woody and other parts may be dissolved away2 and after repeated washing with spirit the starch may be mounted4 ,this1 however1 must never be in any glycerine medium1 except that given on p4 a href,page#agbagb_/;a4 99 99 99 99 99 ,in ,plate ,,iii4 ,fig4 #a1 may be seen a curious little drawing1 which is a sketch of the laurel-leaf cut transversely1 and showing the entire thickness of the leaf4 ,along the top may be seen the delicate layer of 8varnish0 with which the surface of the leaf is covered1 and which serves to give to the foliage its peculiar polish4 ,this varnish is nothing more than the translucent matter which binds all the cells together1 and which is poured out very liberally upon the surface of the leaf4 ,the lower part of this section exhibits the cells of which the leaf is built1 and towards the left hand may be seen a cut end of one of the veins of the leaf1 more rightly called a wood-cell4 ,we will now examine a few examples of surface cells4 ,fig4 #e is a portion of epidermis stripped from a ,capsicum pod1 exhibiting the remains of the nuclei in the centre of each cell1 together with the great thickening of the wall-cells and the numerous pores for the transmission of fluid4 ,this is a very pretty specimen for the microscope1 as it retains its bright red colour1 and even in old and dried pods exhibits the characteristic markings4 ,in the centre of the ,plate may be seen a wheel-like arrangement of the peculiar cells found on the petals of six different flowers1 all easily obtainable1 and mounted without difficulty4 ,fig4 #cj is the petal of a geranium 7,pelargonium71 a very common object on purchased slides4 ,it is a most lovely subject for the microscope1 whether it be examined with a low or a high power1--in the former instance exhibiting a most beautiful 8stippling0 of pink1 white1 and black1 and in the latter showing the six-sided cells with their curious markings4 ,in the centre of each cell is seen a radiating arrangement of dark lines with a light spot in the middle1 looking very like the mountains on a map4 ,these lines were long thought to be hairs2 but ,mr4 ,tuffen ,west1 in an interesting and elaborate paper on the subject1 has shown their true nature4 ,from his observations it seems that the beautiful velvety aspect of flower petals is owing to these arrangements of the surface cells1 and that their rich brilliancy of colour is due to the same cause4 ,the centre of each cell-wall is elevated as if pushed up by a pointed instrument from the under side of the wall1 and in different flowers this elevation assumes different forms4 ,sometimes it is merely a slight wart on the surface1 sometimes it becomes a dome1 while in other instances it is so developed as to resemble a hair4 ,indeed1 ,mr4 ,west has concluded that these elevations are nothing more than rudimentary hairs4 ,the dark radiating lines are shown by the same authority to be formed by wrinkling of the membrane forming the walls of the elevated centre1 and not to be composed of 8secondary deposit10 as has generally been supposed4 ,fig4 #ca represents the petal of the common periwinkle1 differing from that of the geranium by the straight sides of the cell-walls1 which do not present the toothed appearance so conspicuous in the former flower4 ,a number of little tooth-like projections may be seen on the interior of the cells1 their bases affixed to the walls and their points tending toward the centre1 and these teeth are1 according to ,mr4 ,west1 formed of secondary deposit4 ,in ,fig4 #cb is shown the petal of the common garden balsam1 where the cells are elegantly waved on their outlines1 and have plain walls4 ,the petal of the primrose is seen in ,fig4 #cd1 and that of the yellow snapdragon in ,fig4 #cc2 in the latter instance the surface cells assume a most remarkable shape1 running out into a variety of zigzag outlines that quite bewilders the eye when the object is first placed under the microscope4 ,fig4 #ce is the petal of the common scarlet geranium4 ,in several instances these petals are too thick to be examined without some preparation1 and glycerine will be found well adapted for that purpose4 ,the young microscopist must1 however1 beware of forming his ideas from preparations of dried leaves1 petals1 or hairs1 and should always procure them in their fresh state whenever he desires to make out their structure4 ,even a fading petal should not be used1 and if the flowers are gathered for the occasion1 their stalks should be placed in water1 so as to give a series of leaves and petals as fresh as possible4 99 99 99 99 99 ,we now pass from the petal of the flower to the pollen1 that coloured dust1 generally yellow or white1 which is found upon the stamens1 and which is very plentiful in many flowers1 such as the lily and the hollyhock4 ,this substance is found only upon the stamens or anthers of full-blown flowers 7the anthers being the male organs71 and is intended for the purpose of enabling the female portion of the flower to produce fertile seeds4 ,in form the pollen grains are wonderfully diverse1 affording an endless variety of beautiful shapes4 ,in some cases the exterior is smooth and marked only with minute dots1 but in many instances the outer wall of the pollen grain is covered with spikes1 or decorated with stripes or belts4 ,a few examples of the commonest forms of pollen will be found on ,plate ,,iii4 ,fig4 #ag is the pollen of the snowdrop1 which1 as will be seen1 is covered with dots and marked with a definite slit along its length4 ,the dots are simply tubercles in the outer coat of the grain1 and are presumed to be formed for the purpose of strengthening the membrane1 otherwise too delicate1 upon the same principle which gives to 8corrugated0 iron such strength in proportion to the amount of material4 ,fig4 #ah is the pollen of the wall-flower1 shown in two views1 and having many of the same characteristics as that of the snowdrop4 ,fig4 #ai is the pollen of the willow-herb1 and is here given as an illustration of the manner in which the pollen aids in the germination of plants4 ,in order to understand its action1 we must first examine its structure4 ,all pollen-grains are furnished with some means by which their contents when thoroughly ripened can be expelled4 ,in some cases this end is accomplished by sundry little holes called pores2 in others1 certain tiny lids are pushed up by the contained matter2 and in some1 as in the present instance1 the walls are thinned in certain places so as to yield to the internal pressure4 ,when a ripe pollen-grain falls upon the stigma of a flower1 it immediately begins to swell1 and seems to 8sprout0 like a potato in a damp cellar1 sending out a slender 8pollen-tube0 from one or other of the apertures already mentioned4 ,in ,fig4 #ai a pollen-tube is seen issuing from one of the projections1 and illustrates the process better than can be achieved by mere verbal description4 ,the pollen-tubes insinuate themselves between the cells of the stigmas1 and1 continually elongating1 worm their way down the 8style0 until they come in contact with the 8ovules40 ,by very careful dissection of a fertilised stigma1 the beautiful sight of the pollen-tubes winding along the tissues of the style may be observed under a high power of the microscope4 ,the pollen-tube is nothing more than the interior coat of the grain1 very much developed1 and filled with a substance technically named 8fovilla10 composed of 8protoplasm0 7the semi-liquid substance which is found in the interior of cells71 very minute starch grains1 and some apparently oily globules4 ,in order to examine the structure of the pollen-grains properly1 they should be examined under various circumstances--some dry1 others placed in water to which a little sugar has been added1 others in oil1 and it will often be found useful to try the effect of different acids upon them4 ,fig4 #bj is the pollen of the common violet1 and is easily recognisable by its peculiar shape and markings4 ,fig4 #ba is the pollen of the musk-plant1 and is notable for the curious mode in which its surface is belted with wide and deep bands1 running spirally round the circumference4 ,fig4 #bb exhibits the pollen of the apple1 and ,fig4 #bc affords a very curious example of the raised markings upon the surface of the dandelion pollen4 ,in ,fig4 #bd there are also some very wonderful markings1 but they are disposed after a different fashion1 forming a sort of network upon the surface1 and leaving several large free spaces between the meshes4 ,the pollen of the lily is shown in ,fig4 #be1 and is a good example of a pollen-grain covered with the minute dottings which have already been described4 ,figs4 #bf and #bg show two varieties of compound pollen1 found in two species of heath4 ,these compound pollen-grains are not of unfrequent occurrence1 and are accounted for in the following manner4 ,the pollen is formed in certain cavities within the anthers1 by means of the continual subdivision of the 8parent-cells0 from which it is developed4 ,in many cases the form of the grain is clearly owing to the direction in which these cells have divided1 but there is no great certainty on this subject4 ,it will be seen1 therefore1 that if the process of subdivision be suddenly arrested1 the grains will be found adhering to each other in groups of greater or smaller size1 according to the character of the species and the amount of subdivision that has taken place4 ,the reader must1 however1 bear in mind that the whole subject is as yet rather obscure1 and that further discovery may throw doubt on many theories which at present are accepted as established4 ,fig4 #bh shows the pollen of the furze1 in which are seen the longitudinal slits and the numerous dots on the surface2 and ,fig4 #bi is the curiously shaped pollen of the tulip4 ,the two large yellow globular figures at each side of the ,plate represent the pollen of two common flowers2 ,fig4 #cf being that of the crocus1 and ,fig4 #cg a pollen-grain of the hollyhock4 ,as may be seen from the illustration1 the latter is of considerable size1 and is covered with very numerous projections4 ,these serve to raise the grain from a level surface1 over which it rolls with a surprising ease of motion1 so much so indeed that if a little of this substance be placed on a slide and a piece of thin glass laid over it1 the glass slips off as soon as it is in the least inclined1 and forces the observer to fix it with paper or cement before he can place it on the inclined stage of the microscope4 ,the little projections have a very curious effect under a high power1 and require careful focusing to observe them properly2 for the diameter of the grain is so large that the focus must be altered to suit each individual projection4 ,their office is1 probably1 to aid in fertilisation4 99 99 99 99 99 ,the seeds of plants are even easier of examination than the pollen1 and in most cases require nothing but a pocket lens and a needle for making out their general structure4 ,the smaller seeds1 however1 must be placed under the microscope1 many of them exhibiting very curious forms4 ,the external coat of seeds is often of great interest1 and needs to be dissected off before it can be rightly examined4 ,the simplest plan in such a case is to boil the seed well1 press it while still warm into a plate of wax1 and then dissect with a pair of needles1 forceps1 and scissors under water4 ,many seeds may also be mounted in cells as dry objects1 after being thoroughly dried themselves4 ,a few examples of the seeds of common plants are given at the bottom of ,plate ,,iii4 ,fig4 #ch exhibits the fruit1 popularly called the seed1 of the common goosegrass1 or ,galium1 which is remarkable for the array of hooklets with which it is covered4 ,immediately above the figure may be seen a drawing of one of the hooks much magnified1 showing its sharp curve 7,fig4 #ci74 ,it is worthy of remark that the hook is not a simple curved hair1 but a structure composed of a number of cells terminating in a hook4 ,fig4 #dj shows the seed1 or rather the fruit1 of the common red valerian1 and is introduced for the purpose of showing its plumed extremity1 which acts as a parachute1 and causes it to be carried about by the wind until it meets with a proper resting-place4 ,it is also notable for the series of strong longitudinal ribs which support its external structure4 ,on ,fig4 #da is shown a portion of one of the parachute hairs much more magnified4 ,the seed of the common dandelion1 so dear to children in their play-hours1 when they amuse themselves by puffing at the white plumy globes which tip the ripe dandelion flower-stalks1 is a very interesting object even to their parents1 on account of its beautiful structure1 and the wonderful way in which it is adapted to the place which it fills4 ,fig4 #de represents the seed portion of one of these objects1 together with a part of the parachute stem1 the remainder of that appendage being shown lying across the broken stem4 ,the shape of the seed is not unlike that of the valerian1 but it is easily distinguished from that object by the series of sharp spikes which fringe its upper end1 and which serve to anchor the seed firmly as soon as it touches the ground4 ,from this end of the seed proceeds a long slender shaft1 crowned at its summit by a radiating plume of delicate hairs1 each of which is plentifully jagged on its surface1 as may be seen in ,fig4 #df1 which shows a small portion of one of these hairs greatly magnified4 ,these jagged points are evidently intended to serve the same purpose as the spikes below1 and to arrest the progress of the seed as soon as it has found a convenient spot4 ,fig4 #db is the seed of the foxglove1 and ,fig4 #dc the seed of the sunspurge1 or milkwort4 ,fig4 #dg shows the seed of the yellow snapdragon2 remarkable for the membranous wing with which the seed is surrounded1 and which is composed of cells with partially spiral markings4 ,when viewed edgewise1 it looks something like ,saturn with his ring1 or1 to use a more homely but perhaps a more intelligible simile1 like a marble set in the middle of a penny4 ,fig4 #dh is a seed of mullein1 covered with net-like markings on its external surface4 ,these are probably to increase the strength of the external coat1 and are generally found in the more minute seeds4 ,on ,fig4 #ej is shown a seed of the burr-reed2 a structure which is remarkable for the extraordinary projection of the four outer ribs1 and their powerful armature of reverted barbs4 ,fig4 #ea shows another form of parachute seed1 found in the willow-herb1 where the parachute is not expanded nearly so widely as that of the valerian2 neither is it set upon a long slender stem like that of the dandelion1 but proceeds at once from the top of the seed1 widening towards the extremity1 and having a very comet-like appearance4 ,two more seeds only remain1 ,fig4 #di being the seed of ,robin ,hood1 and the other1 ,fig4 #eb1 that of the muskmallow1 being given in consequence of the thick coat of hairs with which it is covered4 ,many seeds can be well examined when mounted in ,canada balsam4 ,,chapter ,,vi ,alg and their ,growth--,desmidiace1 where found--,diatoms1 their ,flinty ,deposit--,volvox--,mould1 ,blight1 and ,mildew--,mosses and ,ferns--,mare's-,tail and the ,spores--,common ,sea-weeds and their ,growth4 ,on ,plate ,,iv4 will be seen many examples of the curious vegetables called respectively alg and fungi1 which exhibit some of the lowest forms of vegetable life1 and are remarkable for their almost universal presence in all parts of this globe1 and also almost all conditions of cold1 heat1 or climate4 ,many of them are well known under the popular name of sea-weeds1 others are equally familiar under the titles of 8mould10 8blight10 or 8mildew10 while many of the minuter kinds exhibit such capability of motion1 and such apparent symptoms of volition1 that they have long been described as microscopic animalcules1 and thought to belong to the animal rather than to the vegetable kingdoms4 ,fig4 #a represents one of the very lowest forms of vegetable life1 being known to the man of science as the ,palmella1 and to the general public as 8gory dew40 ,it may be seen on almost any damp wall1 extending in red patches of various sizes1 looking just as if some blood had been dashed on the wall1 and allowed to dry there4 ,with a tolerably powerful lens this substance can be resolved into the exceedingly minute cells depicted in the figure4 ,generally1 these cells are single1 but in many instances they are double1 owing to the process of subdivision by which the plant grows1 if such a term may be used4 ,fig4 #b affords an example of another very low form of vegetable1 the ,palmogla1 that green slimy substance which is so common on damp stones4 ,when placed under the microscope1 this plant is resolvable into a multitude of green cells1 each being surrounded with a kind of gelatinous substance4 ,the mode of growth of this plant is very simple4 ,a line appears across one of the cells1 and after a while it assumes a kind of hour-glass aspect1 as if a string had been tied tightly round its middle4 ,by degrees the cell fairly divides into two parts1 and then each part becomes surrounded with its own layer of gelatine1 so as to form two separate cells1 placed end to end4 ,one of the figures1 that on the right hand1 represents the various processes of 8conjugation10 i4e4 the union and fusion together of two cells4 ,each cell throws out a little projection2 these meet together1 and then uniting1 form a sort of isthmus connecting the two main bodies4 ,this rapidly widens1 until the two cells become fused into one large body4 ,the whole subject of conjugation is very interesting1 and is treated at great length in the ,micrographic ,dictionary of ,messrs4 ,griffith and ,henfrey1 a work to which the reader is referred for further information on many of the subjects that1 in this small work1 can receive but a very hasty treatment4 ,few persons would suppose that the slug-like object on ,fig4 #c1 the little rounded globules with a pair of hair-like appendages1 and the round disc with a dark centre1 are only different forms of the same organism4 ,such1 however1 is the case1 and these are three of the modifications which the ,protococcus undergoes4 ,this vegetable may be seen floating like green froth on the surface of rain-water4 ,on collecting some of this froth and putting it under the microscope1 it is seen to consist of a vast number of little green bodies1 moving briskly about in all directions1 and guiding their course with such apparent exercise of volition that they might very readily be taken for animals4 ,it may be noticed that the colour of the plant is sometimes red1 and in that state it has been called the ,hmatococcus4 ,the 8still0 state of this plant is shown in the round disc4 ,after a while the interior substance splits into two portions2 these again subdivide1 and the process is repeated until sixteen or thirty-two cells become developed out of the single parent-cell4 ,these little ones then escape1 and1 being furnished with two long 8cilia0 or thread-like appendages1 whirl themselves merrily through the water4 ,when they have spent some time in this state1 growing all the while1 they lose their cilia1 become clothed with a strong envelope1 and pass into the still stage from which they had previously emerged4 ,this curious process is repeated in endless succession1 and causes a very rapid growth of the plant4 ,the moving bodies are technically called zoospores1 or living spores1 and are found in many other plants besides those of the lowest order4 ,,iv4 ,,fig4 #a4 ,gory ,dew1 ,palmella cruenta #b4 ,palmogla macrococca #c4 ,protococcus pluvialis1 a1 in its motile1 b1 in its fixed state1 c1 zoospores #d4 ,closterium #e4 ,ditto1 end more magnified #f4 ,pediastrum #g4 ,scenedesmus #h4 ,oscillatoria #i4 ,spirogyra #aj4 ,tyndaridea #aa4 ,do4 spore #ab4 ,sphrozosma #ac4 ,chlorococcus #ad4 ,scenedesmus #ae4 ,pediastrum1 to show cells #af4 ,ankistrodesmus #ag4 ,cosmarium #ah4 ,desmidium #ai4 ,cosmarium1 formation of ,resting ,spore #bj4 ,cocconema lanceolatum #ba4 ,diatoma vulgare ,do4 larger frustules1 at the side #bb4 ,volvox globator ,do4 single green body1 above #bc4 ,synedra #bd4 ,gomphonema acuminatum ,do4 larger frustules1 below #be4 ,yeast #bf4 ,sarcina ventriculi #bg4 ,eunotia diadema #bh4 ,melosira varians ,do4 two bleached frustules #bi4 ,cocconeis pediculus #cj4 ,achnanthes exilis #ca4 ,navicula amphisbna #cb4 ,uredo1 8,red-rust0 of corn #cc4 ,puccinea1 ,mildew of corn #cd4 ,botrytis1 mould on grapes ,do4 ,sporules1 beside it #ce4 ,do4 parasitica1 ,potato blight #cf4 ,ectocarpus siliculosus #cg4 ,ulva latissima #ch4 ,polypodium ,do4 single spore1 below #ci4 ,moss capsule1 ,hypnum #dj4 ,mare's tail1 ,equisetum1 a ,do4 do4 b and c #da4 ,porphyra laciniata ,illustration3 ,,iv4 ,on ,fig4 #ac is delineated a very minute plant1 called from its colour ,chlorococcus4 ,it may be found upon tree-trunks1 walls1 etc41 in the form of green dust1 and has recently been found to take part in forming the first stage of lichens4 ,a large and interesting family of the 8confervoid alg10 as these low forms of vegetable life are termed1 is the ,desmidiace1 called in more common parlance desmids4 ,a few examples of this family are given in ,plate ,,iv4 ,they may be found in water1 always preferring the cleanest and the brightest pools1 mostly congregating in masses of green film at the bottom of the water1 or investing the stems of plants4 ,their removal is not very easy1 but is best accomplished by very carefully taking up this green slippery substance in a spoon1 and straining the water away through fine muslin4 ,they may also be separated by allowing a ring1 covered with muslin1 to float upon the surface of the water collected in a jar1 for1 being great lovers of light1 they assemble where it is most abundant4 ,an opaque jar should be used4 ,for preservation1 glycerine-gelatine seems to be the best fluid4 ,a very full and accurate description of these plants may be found in ,ralfs' ,british ,desmidie4 ,fig4 #d represents one of the species of ,closterium1 more than twenty of which are known4 ,these beautiful objects can be obtained from the bottom of almost every clear pool1 and are of some interest on account of the circulating currents that may be seen within the living plants4 ,a high power is required to see this phenomenon clearly4 ,the ,closteria are reproduced in various ways4 ,mostly they divide across the centre1 being joined for a while by two half-cells4 ,sometimes they reproduce by means of conjugation1 the process being almost entirely conducted on the convex sides4 ,fig4 #e represents the end of a ,closterium1 much magnified in order to show the actively moving bodies contained within it4 ,fig4 #af is a supposed desmid1 called ,ankistrodesmus1 and presumed to be an earlier stage of ,closterium4 ,fig4 #f is a very pretty desmid called the ,pediastrum1 and valuable to the microscopist as exhibiting a curious mode of reproduction4 ,the figure shows a perfect plant composed of a number of cells arranged systematically in a star-like shape2 ,fig4 #ae is the same species without the colouring matter1 in order to show the shape of the cells4 ,the ,pediastrum reproduces by continual subdivision of the contents of each cell into a number of smaller cells1 termed 8gonidia0 on account of their function on the perpetuation of the species4 ,when a sufficient number has been formed1 they burst through the envelope of the original cell1 taking with them a portion of its internal layer1 so as to form a vesicle1 in which they move actively4 ,in a few minutes they arrange themselves in a circle1 and after a while they gradually assume the perfect form1 the whole process occupying about two days4 ,fig4 #ah exhibits an example of the genus ,desmidium4 ,in this genus the cells are either square or triangular in their form1 having two teeth at their angles1 and twisted regularly throughout their length1 causing the wavy or oblique lines which distinguish them4 ,the plants of this genus are common1 and may be found almost in any water4 ,i may as well mention that ,i have obtained nearly all the preceding species1 together with many others1 from a little pond on ,blackheath4 ,fig4 #g is another desmid called ,scenedesmus1 in which the cells are arranged in rows of from two to ten in number1 the cell at each extremity being often furnished with a pair of bristle-like appendages4 ,fig4 #ad is another species of the same plant1 and both may be found in the water supplied for drinking in ,london1 as well as in any pond4 ,a common species of desmid is seen at ,fig4 #ab1 called ,sphrozosma1 looking much like a row of stomata set chainwise together4 ,it multiplies by self-division4 ,fig4 #ag is a specimen of desmid named ,cosmarium1 plentifully found in ponds on heaths and commons1 and having a very pretty appearance in the microscope1 with its glittering green centre and beautifully transparent envelope4 ,the manner in which the ,cosmarium conjugates is very remarkable1 and is shown at ,fig4 #ai4 ,the two conjugating cells become very deeply cleft1 and by degrees separate1 suffering the contents to pour out freely1 and1 as at present appears1 without any envelope to protect them4 ,the mass1 however1 soon acquires an envelope of its own1 and by degrees assumes a dark reddish-brown tint4 ,it is now termed a sporangium1 and is covered with a vast number of projections1 which in this genus are forked at their tip1 but in others1 which also form sporangia1 are simply pointed4 ,the ,closteria conjugate after a somewhat similar manner1 and it is not unfrequent to find a pair in this condition1 but in their case the sporangium is quite smooth on its surface4 ,another very remarkable family of confervoid alg is that which is known under the name of ,oscillatori1 from the oscillating movement of the plant4 ,they are always long and filamentous in character1 and may be seen moving up and down with a curious irregularity of motion4 ,their growth is extremely rapid1 and may be watched under a tolerably powerful lens1 thus giving many valuable hints as to the mode by which these plants are reproduced4 ,one of the commonest species is represented at ,fig4 #h4 ,figs4 #i1 #aj1 and #aa are examples of another family1 called technically the ,zygnemace1 because they are so constantly yoked together by conjugation4 ,they all consist of a series of cylindrical cells1 set end to end1 and having their green contents arranged in similar patterns4 ,two of the most common and typical species are here given4 ,fig4 #i is the ,spirogyra1 so called from the spiral arrangement of the chlorophyll2 and ,fig4 #aj is the ,tyndaridea1 or ,zygnema1 as it is called by some writers4 ,a casual inspection will show how easy it is to distinguish the one from the other4 ,fig4 #aa represents a portion of the ,tyndaridea during the process of conjugation1 showing the tube of connection between the cells and one of the spores4 99 99 99 99 99 ,we now arrive at the diatoms1 so called because of their method of reproduction1 in which it appears as if a cut were made right along the original cell4 ,the commonest of these plants is the ,diatma vulgre1 seen in ,fig4 #ba as it appears while growing4 ,the reproduction of this plant is effected by splitting down the centre1 each half increasing to the full size of the original cell2 and in almost every specimen of water taken from a pond1 examples of this diatom undergoing the process of division will be distinguished4 ,it also grows by conjugation4 ,the diatoms are remarkable for the delicate shell or flinty matter which forms the cell skeleton1 and which will retain its shape even after intense heat and the action of nitric acid4 ,while the diatoms are alive1 swimming through the water1 their beautiful markings are clearly distinct1 glittering as if the form were spun from crystalline glass4 ,just above the figure1 and to the right hand1 are two outlines of single cells of this diatom1 the one showing the front view and the other the profile4 ,fig4 #bj is an example of a diatom--,cocconma lanceoltum--furnished with a stalk4 ,the left-hand branch sustains a 8frustule0 exhibiting the front view1 while the other is seen sideways4 ,another common diatom is shown in ,fig4 #bc1 and is known by the name of ,synedra4 ,this constitutes a very large genus1 containing about seventy known species4 ,in this genus the frustules are at first arranged upon a sort of cushion1 but in course of time they mostly break away from their attachment4 ,in some species they radiate in every direction from the cushion1 like the spikes of the ancient cavalier's mace4 ,fig4 #bd is another stalked diatom called ,gomphonma acumintum1 found commonly in ponds and ditches4 ,there are nearly forty species belonging to this genus4 ,a pair of frustules are also shown which exhibit the beautiful flinty outline without the coloured contents 7technically called endochrome74 ,fig4 #bg is a side view of a beautiful diatom1 called ,euntia diadma from its diadem-like form4 ,there are many species of this genus4 ,when seen upon the upper surface1 it looks at first sight like a mere row of cells with a band running along them2 but by careful arrangement of the light its true form may easily be made out4 ,fig4 #bh represents a very common fresh-water diatom1 named ,melosra vrians4 ,the plants of this genus look like a cylindrical rod composed of a variable number of segments1 mostly cylindrical1 but sometimes disc-shaped or rounded4 ,an end view of one of the frustules is seen at the left hand1 still coloured with its dots of 8endochrome10 and showing the cylindrical shape4 ,immediately above is a figure of another frustule seen under both aspects with the endochrome removed4 ,a rather curious species of diatom1 called ,coccones pedculus1 is seen at ,fig4 #bi as it appears on the surface of common water-cress4 ,sometimes the frustules1 which in all cases are single1 are crowded very closely upon each other and almost wholly hide the substance on which they repose4 ,fig4 #cj is another diatom of a flag-like shape1 named ,achnanthes1 having a long slender filament attached to one end of the lower frustule1 representing the flag-staff4 ,there are many wonderful species of such diatoms1 some running almost end to end like a bundle of sticks1 and therefore called ,bacillria2 others spreading out like a number of fans1 such as the genus ,licmophora2 while some assume a beautiful wheel-like aspect1 of which the genus ,meridion affords an excellent example4 ,a very remarkable1 and not uncommon1 fresh-water diatom is the ,bacillria paradxa4 ,it looks1 when at rest1 like a broad brown ribbon of varying length4 ,the diatoms lie across the ribbon1 on edge1 and slide upon each other exactly like the ladders of a fire-escape1 so that the broad ribbon is converted into a fine long thread1 which speedily closes up again into the original ribbon1 and so da capo4 ,the reason for this movement1 and how it is effected1 is absolutely unknown2 indeed1 nothing certain is known as to the way in which diatoms move1 nor has ever a probable guess yet been made4 ,the last of the diatoms which we shall be able to mention in this work is that represented on ,fig4 #ca4 ,the members of this genus have the name of ,navcula1 on account of their boat-like shape and their habit of gliding through the water in a canoe-like fashion4 ,there are many species of this genus1 all of which are notable for the graceful and varied courses formed by their outlines1 and the extreme delicacy of their markings4 ,in many species the markings are so extremely minute that they can only be made out with the highest powers of the microscope and the most careful illumination1 so that they serve as test objects whereby the performance of a microscope can be judged by a practical man4 99 99 99 99 99 ,the large spherical figure in the centre of ,plate ,,iv4 represents an example of a family belonging to the confervoid alg1 and known by the name of ,volvox globator4 ,there seems to be but one species known4 ,this singular plant has been greatly bandied about between the vegetable and animal kingdoms1 but seems now to be satisfactorily settled among the vegetables4 ,in the summer it may be found in pools of water1 sufficiently large to be visible to the naked eye1 like a little green speck proceeding slowly through the water4 ,when a moderate power is used1 it appears as shown in the figure1 and always contains within its body a number of smaller individuals1 which after a while burst through the envelope of the parent and start upon an independent existence4 ,on a closer examination1 a further generation may be discovered even within the bodies of the children4 ,the whole surface is profusely covered with little green bodies1 each being furnished with a pair of movable cilia1 by means of which the whole organism is moved through the water4 ,these bodies are analogous to the zoospores already mentioned1 and are connected with each other by a network of filaments4 ,reproduction also takes place by conjugation as in other alg4 ,a more magnified representation of one of the green bodies is shown immediately above the larger figure4 ,the volvox is apt to die soon when confined in a bottle4 ,fig4 #be is the common yeast-plant1 consisting simply of a chain of cells1 which increase by budding1 and only form spores when they have exhausted the nutriment in the fluid in which they live4 ,fig4 #bf is a curious object1 whose scientific name is ,srcina ventrculi4 ,it is found in the human stomach4 ,similar forms are often to be found in the air2 for instance1 a piece of cocoa-nut will exhibit this1 and many other kinds of ,bacteria and moulds1 after a few days' exposure to the air1 preferably in a dark cupboard4 ,we now come upon a few of the blights and mildews4 ,a very interesting series of forms is first to be alluded to4 ,upon the bramble-leaf may often be found spots1 at first red1 then orange1 then reddish black4 ,these are known as cidium berberidis4 ,fig4 #cb shows the 8red-rust0 of wheat1 the ,urdo2 and ,fig4 #cc is the mildew of corn1 known as ,puccinia4 ,the interest lies in the fact that these three forms are successive stages in the life-history of the same plant4 ,another species of ,urdo1 together with a ,phragmdium1 once thought to be another kind of fungus1 is seen on a rose-leaf on ,plate ,v4 ,fig4 #a4 ,on ,fig4 #aj1 however1 of the same ,plate1 the ,phragmdium may be seen proceeding from ,urdo1 thus proving them to be but two states of the same plant4 ,there is room for any amount of observation and work in connection with the life-histories of many of these fungi4 ,another species of ,puccinia1 found on the thistle1 is shown on ,plate ,v4 ,fig4 #g4 ,fig4 #cd is the mould found upon decaying grapes1 and called therefrom1 or from the clustered spores1 ,botrtis4 ,some of the detached spores are seen by its side4 ,fig4 #ce is another species of the same genus1 termed ,botrtis parastica1 and is the cause of the well-known 8potato-disease40 ,the mosses and ferns afford an endless variety of interesting objects to the microscopist2 but as their numbers are so vast1 and the details of their structure so elaborate1 they can only be casually noticed in the present work4 ,fig4 #ch represents a spore-case of the ,polypodium1 one of the ferns1 as it appears while in the act of bursting and scattering the contents around4 ,one of the spores is seen more magnified below4 ,the spore-cases of many ferns may be seen bursting under the microscope1 and have a very curious appearance1 writhing and twisting like worms1 and then suddenly filling the field with a cloud of spores4 ,fig4 #i1 ,plate ,v41 is a piece of the brown1 chaff-like1 scaly structure found at the base of the stalk of male fern cells1 showing the manner in which a flat membrane is formed4 ,fig4 #ci is a capsule of the ,hypnum1 one of the mosses1 showing the beautiful double fringe with which its edge is crowned4 ,fig4 #b1 ,plate ,v41 is the capsule of another moss1 ,polytrchum1 to show the toothed rim2 on the right hand is one of the teeth much more magnified4 ,fig4 #c1 ,plate ,v41 is the capsule of the ,jungermannia1 one of the liverworts1 showing the 8elaters0 bursting out on every side1 and scattering the spores4 ,fig4 #d is a single elater much magnified1 showing it to be a spirally coiled filament1 that1 by sudden expansion1 shoots out the spores just as a child's toy-gun discharges the arrow4 ,fig4 #e is a part of the leaf of the ,sphagnum moss1 common in fresh water1 showing the curious spiral arrangement of secondary fibre which is found in the cells1 as well as the circular pores which are found in each cell at a certain stage of growth4 ,just below1 and to the left hand1 is a single cell greatly magnified1 in order to show these peculiarities more strongly4 ,fig4 #h is part of a leaf of ,jungermannia1 showing the dotted cells4 ,fig4 #f1 ,plate ,v41 is a part of a rootlet of moss1 showing how it is formed of cells elongated and joined end to end4 ,on the common mare's-tail1 or ,equistum1 may be seen a very remarkable arrangement for scattering the spores4 ,on the last joint of the stem is a process called a fruit-spike1 being a pointed head around which are set a number of little bodies just like garden-tables1 with their tops outward4 ,one of these bodies is seen in ,fig4 #dj4 ,from the top of the table depend a number of tiny pouches1 which are called sporangia2 these lie closely against each other1 and contain the spores4 ,at the proper moment these pouches burst from the inside1 and fling out the spores1 which then look like round balls with irregular surfaces1 as shown in ,fig4 #dj1 c4 ,this irregularity is caused by four elastic filaments1 knobbed at the end1 which are originally coiled tightly round the body of the spore1 but by rapidly untwisting themselves cause the spore to leap about1 and so aid in the distribution4 ,a spore with uncoiled filaments is seen at ,fig4 #dj1 b4 ,by breathing on them they may be made to repeat this process at will4 ,fig4 #cf is a common little sea-weed1 called ,ectocarpus siliculsus1 that is found parasitically adhering to large plants1 and is figured in order to show the manner in which the extremities of the branches are developed into sporangia4 ,fig4 #cg is a piece of the common green laver1 ,ulva latssima1 showing the green masses that are ultimately converted into zoospores1 and by their extraordinary fertility cause the plant to grow with such rapid luxuriance wherever the conditions are favourable4 ,every possessor of a marine aquarium knows how rapidly the glass sides become covered with growing masses of this plant4 ,the smaller figure above is a section of the same plant1 showing that it is composed of a double plate of cellular tissue4 ,fig4 #da is a piece of purple laver or 8sloke10 ,porphra lacinita1 to show the manner in which the cells are arranged in groups of four1 technically named 8tetraspores40 ,this plant has only one layer of cells4 ,on ,plate ,v4 may be seen a number of curious details of the higher alg4 ,fig4 #aa is the ,sphacelria1 so called from the curious capsule cells found at the end of the branches1 and termed sphacel4 ,this portion of the plant is shown more magnified in ,fig4 #ab4 ,another sea-weed is represented in ,fig4 #ac1 in order to show the manner in which the fruit is arranged2 and a portion of the same plant is given on a larger scale at ,fig4 #ad4 ,a very pretty little sea-weed called ,cermium is shown at ,fig4 #ae2 and a portion showing the fruit much more magnified is drawn at ,fig4 #bb4 ,fig4 #bc is a little alga called ,myrionma1 growing parasitically on the preceding plant4 ,fig4 #af is a section of a capsule belonging to the ,hlydris siliqusa1 showing the manner in which the fruit is arranged2 and ,fig4 #ag shows one of the spores more magnified4 ,fig4 #ah shows the ,polysiphnia parastica1 a rather common species of a very extensive genus of sea-weeds1 containing nearly three hundred species4 ,fig4 #ai is a portion of the stem of the same plant1 cut across in order to show the curious mode in which it is built up of a number of longitudinal cells1 surrounding a central cell of large dimensions1 so that a section of this plant has the aspect of a rosette when placed under the microscope4 ,a capsule or 8ceramdium0 of the same plant is shown at ,fig4 #bj1 for the purpose of exhibiting the pear-shaped spores1 and the mode of their escape from the parent-cell previous to their own development into fresh plants4 ,the same plant has another form of reproduction1 shown in ,fig4 #ba1 where the 8tetraspores0 are seen imbedded in the substance of the branches4 ,there is yet a third mode of reproduction by means of 8antheridia10 or elongated white tufts at the extremities of the branches4 ,the cells produced by these tufts fertilise the rudimentary capsules1 and so fulfil the function of the pollen in flowering plants4 ,fig4 #be is the ,cladphora1 a green alga1 figured to illustrate its mode of growth2 and ,fig4 #bf represents one of the red sea-weeds1 ,ptilta legans1 beautifully feathered1 and with a small portion shown also on a larger scale1 in order to show its structure more fully4 ,a good contrast to this species is seen on ,fig4 #bg1 and the mode in which the long1 slender1 filamentary fronds are built up of many-sided cells is seen just to the left hand of the upper frond4 ,fig4 #bd is a portion of the lovely ,delessria sangunea1 given in order to show the formation of the cells1 as also the arrangement by which the indistinct nervures are formed4 ,v4 ,,fig4 #a4 ,rose ,leaf1 with fungus #b4 ,moss capsule1 ,polytrichum #c4 ,jungermannia1 capsule #d4 ,do4 an elater more magnified #e4 ,leaf of ,moss1 ,sphagnum #f4 ,rootlet1 ,moss #g4 ,puccinia1 from ,thistle #h4 ,jungermannia1 leaf #i4 ,scale from stalk of male fern #aj4 ,uredo #aa4 ,sphacelaria filicina #ab4 ,do4 top1 more magnified #ac4 ,seaweed1 showing fruit #ad4 ,do4 fruit1 more magnified #ae4 ,ceramium #af4 ,capsule1 ,halidrys #ag4 ,spore of do4 #ah4 ,polysiphonia parasitica #ai4 ,do4 stem1 more magnified #bj4 ,do4 ,capsule1 tetraspores escaping #ba4 ,do4 fruit1 another form #bb4 ,ceramium1 fruit #bc4 ,myrionema1 parasitic ,seaweed #bd4 ,delesseria sanguinea1 ,frond #be4 ,cladophora #bf4 ,ptilota elegans #bg4 ,enteromorpha clathrata #bh4 ,nitophyllum laceratum ,illustration3 ,v4 ,the figure on the bottom left-hand corner of ,plate ,v4 is a portion of the pretty ,nitophyllum lacertum1 a plant belonging to the same family as the preceding one4 ,the specimen here represented has a gathering of spores upon the frond1 in which state the frond is said to be 8in fruit40 ,fig4 #bg represents a portion of the common sea-grass 7,enteromorpha71 so common on rocks and stones between the range of high and low water4 ,on the left hand of the figure1 and near the top1 is a small piece of the same plant much more magnified1 in order to show the form of its cells4 ,,chapter ,,vii ,antenn1 their ,structure and ,use--,eyes1 ,compound and ,simple--,breathing ,organs--,jaws and their ,appendages--,legs1 ,feet1 and ,suckers--,digestive ,organs--,wings1 ,scales1 and ,hairs--,eggs of ,insects--,hair1 ,wool1 ,linen1 ,silk1 and ,cotton--,scales of ,fish--,feathers--,skin and its ,structure--,epithelium--,nails1 ,bone1 and ,teeth--,blood ,corpuscles and ,circulation--,elastic ,tissues--,muscle and ,nerve4 ,we now take leave of the vegetables for a time1 and turn our attention to the animal kingdom4 ,on ,plate ,,vi4 may be seen many beautiful examples of animal structures1 most of them being taken from the insect tribes4 ,we will begin with the antenn1 or horns1 as they are popularly termed1 of the insect4 ,the forms of these organs are as varied as those of the insects to which they belong1 and they are so well defined that a single antenna will1 in almost every instance1 enable a good entomologist to designate the genus to which the insect belonged4 ,the functions of the antenn are not satisfactorily ascertained4 ,they are certainly often used as organs of speech1 as may be seen when two ants meet each other1 cross their antenn1 and then start off simultaneously to some task which is too much for a single ant4 ,this pretty scene may be witnessed on any fine day in a wood1 and a very animated series of conversations may readily be elicited by laying a stick across their paths1 or putting a dead mouse or large insect in their way4 ,i once saw a very curious scene of this kind take place at an ant's nest near ,hastings4 ,a great daddy long-legs had1 unfortunately for itself1 settled on the nest1 and was immediately 8pinned0 by an ant or two at each leg1 so effectually that all its struggles availed nothing4 ,help was1 however1 needed1 and away ran four or five ants in different directions1 intercepting every comrade they met1 and by a touch of the antenn sending them off in the proper direction4 ,a large number of the wise insects soon crowded round the poor victim1 whose fate was rapidly sealed4 ,every ant took its proper place1 just like a gang of labourers under the orders of their foreman2 and by dint of pushing and pulling1 the long-legged insect was dragged to one of the entrances of the nest1 and speedily disappeared4 ,many of the ichneumon-flies may also be seen quivering their antenn with eager zeal1 and evidently using them as feelers1 to ascertain the presence of the insect in which they intend to lay their eggs2 and many other similar instances will be familiar to anyone who has been in the habit of watching insects and their ways4 ,it is1 however1 most likely that the antenn serve other purposes than that which has just been mentioned1 and many entomologists are of opinion that they serve as organs of hearing4 ,fig4 #ae1 ,plate ,,vi41 represents a part of one of the joints belonging to the antenn of the common house-fly2 it is seen to be covered with a multitude of little depressions1 some being small1 and others very much larger4 ,a section of the same antenna1 but on a larger scale1 is shown by ,fig4 #af1 in order to exhibit the real form of these depressions4 ,nerves have been traced to these curious cavities1 which evidently serve some very useful purpose1 some authors thinking them to belong to the sense of smell1 and others to that of hearing4 ,perhaps they may be the avenues of some sensation not possessed by the human race1 and of which we are therefore ignorant4 ,fig4 #ag represents a section of the antenn of an ichneumon-fly1 to show the structure of these organs of sense4 ,we will now glance cursorily at the forms of antenn which are depicted in the ,plate4 ,fig4 #a is the antenna of the common cricket1 which consists of a vast number of little joints1 each a trifle smaller than the preceding one1 the whole forming a long1 thread-like organ4 ,fig4 #b is taken from the grasshopper1 and shows that the joints are larger in the middle than at either end4 ,figs4 #c and #e are from two minute species of cocktailed beetles 7,staphylnid71 which swarm throughout the summer months1 and even in the winter may be found in profusion under stones and moss4 ,the insect from which ,fig4 #e was taken is so small that it is almost invisible to the naked eye1 and was captured on the wing by waving a sheet of gummed paper under the shade of a tree4 ,these are the tiresome little insects that so often get into the eye in the summer1 and cause such pain and inconvenience until they are removed4 ,fig4 #d shows the antenna of the tortoise beetle 7,cssida71 so common on many leaves1 and remarkable for its likeness to the reptile from which it derives its popular name4 ,fig4 #c is from one of the weevils1 and shows the extremely long basal joint of the antenn of these beetles1 as well as the clubbed extremity4 ,fig4 #g is the beautifully notched antenna of the cardinal beetle 7,pyrochra71 and ,fig4 #aa is the fan-like one of the common cockchafer4 ,this specimen is taken from a male insect1 and the reader will find his trouble repaid on mounting one of these antenn as a permanent object4 ,fig4 #ab is an antenna from one of the common ground beetles 7,crabus7 looking like a string of elongated pears1 from the form of the joints4 ,the reader will see that in beetles he is sure to find eleven joints in the antenn4 ,fig4 #aj is the entire antenna of a fly 7,syrphus71 one of those pretty flies which may be seen hovering over one spot for a minute1 and then darting off like lightning to hang over another4 ,the large joint is the one on which are found those curious depressions that have already been mentioned4 ,fig4 #h is one of the antenn of a tortoise-shell butterfly 7,vanessa71 showing the slender1 knobbed form which butterfly antenn assume2 and ,figs4 #ac and #ad are specimens of moths' antenn1 showing how they always terminate in a point4 ,fig4 #ac is the beautiful feathery antenna of the ermine moth 7,spilosma72 and ,fig4 #ad is the toothed one of the tiger moth 7,arctia caja74 ,in all these feathered and toothed antenn of moths1 the male insects have them much more developed than the female1 probably for the purpose of enabling them to detect the presence of their mates1 a property which some possess in wonderful perfection4 ,the male oak-egger moth1 for example1 can be obtained in any number by putting a female into a box with a perforated lid1 placing the box in a room1 and opening the window4 ,in the course of the evening seven or eight males are seen to make their appearance1 and they are so anxious to get at their intended mate that they will suffer themselves to be taken by hand4 ,fig4 #i is an antenna of the male gnat1 a most beautiful object1 remarkable for the delicate transparency of the joints1 and the exquisitely fine feathering with which they are adorned4 ,we now arrive at the eyes of the insects1 all of which are very beautiful1 and many singularly full of interest4 ,in the centre of ,plate ,,vi4 may be seen the front view of the head of a bee1 showing both kinds of eyes1 three simple eyes arranged triangularly in the centre1 and two large masses1 compound eyes1 at the sides4 ,the simple eyes1 termed 8ocelli10 are from one to three in number1 and usually arranged in a triangular form between the two compound eyes4 ,externally they look merely like shining rounded projections1 and can be seen to great advantage in the dragon-flies4 ,the compound eyes may be considered as aggregations of simple eyes1 set closely together1 and each assuming a more or less perfect six-sided form4 ,their number varies very greatly2 in some insects1 such as the common fly1 there are about four thousand of these simple eyes in one compound one1 in the ant only fifty1 in the dragon-fly about twelve thousand1 and in one of the beetles more than twenty-five thousand4 ,fig4 #ah shows a portion of the compound eye of the ,atalanta butterfly1 and ,fig4 #bj the same organ of the death's-head moth4 ,a number of the protecting hairs may be seen still adhering to the eye of the butterfly4 ,fig4 #bb is a remarkably good specimen of the eye of a fly 7,heliphilus71 showing the facets1 nearly square1 the tubes to which they are attached1 and portions of the optic nerves4 ,fig4 #bc is part of the compound eye of a lobster1 showing the facets quite square4 ,all these drawings were taken by the camera lucida from my own preparations1 so that ,i can answer for their authenticity4 ,on ,plate ,,viii4 ,figs4 #f and #ab1 the reader will find two more examples of eyes1 these being taken from the spiders4 ,fig4 #f is an example of the eight eyes of the well-known zebra spider1 so common on our garden walls and similar situations1 hunting incessantly after flies and other prey1 and capturing them by a sudden pounce4 ,the eyes are like the ocelli of insects1 and are simple in their construction4 ,the number1 arrangement1 and situation of the eyes is extremely varied in spiders1 and serves as one of the readiest modes of distinguishing the species4 ,fig4 #ab1 ,plate ,,viii41 represents one of the curious eyes of the common harvest spider1 perched on a prominence or 8watch-tower0 7as it has been aptly named71 for the purpose of enabling the creature to take a more comprehensive view of surrounding objects4 99 99 99 99 99 ,returning to ,plate ,,vi41 in ,fig4 #ba we see a curiously branched appearance1 something like the hollow root of a tree1 and covered with delicate spiral markings4 ,this is part of the breathing apparatus of the silkworm1 extracted and prepared by myself for the purpose of showing the manner in which the tubes branch off from the 8spiracle0 or external breathing-hole1 a row of which may be seen along the sides of insects1 together with the beautiful spiral filament which is wound round each tube for the purpose of strengthening it4 ,one of these spiracles may be seen in the neck of the gnat 7,fig4 #bg74 ,another spiracle1 more enlarged1 may be seen on ,plate ,,vii4 ,fig4 #cd1 taken from the wireworm1 i4e4 the larva of the skipjack beetle 7,elter71 to show the apparatus for excluding dust and admitting air4 ,the object of the spiral coil is very evident1 for as these breathing-tubes extend throughout the whole body and limbs1 they would fail to perform their office when the limbs were bent1 unless for some especial provision4 ,this is achieved by the winding of a very strong but slender filament between the membranes of which the tube is composed1 so that it always remains open for the passage of air throughout all the bends to which it may be subjected4 ,flexible tubes for gas and similar purposes are made after the same fashion1 spiral metal wire being coiled within the india-rubber pipe4 ,a little piece of this thread is seen unwound at the end of a small branch towards the top1 and this thread is so strong that it retains its elasticity when pulled away from the tube1 and springs back into its spiral form4 ,i have succeeded in unwinding a considerable length of this filament from the breathing-tube of a humble bee4 ,fig4 #bh represents the two curious tubercles upon the hinder quarters of the common green-blight1 or ,aphis1 so very common on our garden plants1 as well as on many trees and other vegetables4 ,from the tips of these tubercles exudes a sweet colourless fluid1 which1 after it has fallen upon the leaves1 is popularly known by the name of honey-dew4 ,ants are very fond of this substance1 and are in the habit of haunting the trees upon which the aphides live1 for the purpose of sucking the honey-dew as it exudes from their bodies4 ,a drop of this liquid may be seen on the extremity of the lower tubercle4 ,the head of the same insect may be seen in ,fig4 #bd1 where the reader may observe the bright scarlet eye1 and the long beak with which the aphis punctures the leaves and sucks the sap4 ,fig4 #bi is the head of the sheep-tick1 exhibiting the organ by which it pierces the skin of the creature on which it lives4 ,fig4 #be is the head of another curious parasite found upon the tortoise1 and remarkable for the powerful hooked apparatus which projects in front of the head4 ,turning to ,plate ,,vii4 ,fig4 #d1 we find the head of a ground beetle 7,crabus71 valuable as exhibiting the whole of the organs of the head and mouth4 ,immediately above the compound eyes are seen the roots of the antenn1 those organs themselves being cut away4 ,above there are two pairs of similarly constructed organs termed the 8maxillary palpi10 because they belong to the lesser jaws or maxill1 seen just within the pair of great curved jaws called the mandibles1 which are extended in so threatening a manner4 ,the 8labial palpi10 so called because they belong to the 8labium10 or under lip1 are seen just within the others2 the tongue is seen between the maxill1 and the chin or 8mentum0 forms a defence for the base of the maxill and the palpi4 ,a careful examination of a beetle's mouth with the aid of a pocket lens is very instructive as well as interesting4 ,fig4 #a on the same ,plate shows the jaws of the hive bee1 where the same organs are seen modified into many curious shapes4 ,in the centre may be seen the tongue1 elongated into a flexible and hair-covered instrument1 used for licking the honey from the interior of flowers4 ,at each side of the tongue are the labial palpi1 having their outermost joints very small1 and the others extremely large1 the latter acting as a kind of sheath for the tongue4 ,outside the labial palpi are the maxill1 separated in the specimen1 but capable of being laid closely upon each other1 and outside all are the mandibles4 ,,vi4 ,,fig4 #a4 ,antenna1 ,cricket #b4 ,do4 ,grasshopper #c4 ,do4 ,staphylinus #d4 ,do4 ,cassida #e4 ,do4 ,staphylinus #f4 ,do4 ,weevil #g4 ,do4 ,pyrochroa #h4 ,do4 ,butterfly1 ,tortoiseshell #i4 ,do4 ,gnat1 male #aj4 ,do4 ,syrphus #aa4 ,do4 ,cockchafer1 male #ab4 ,do4 ,ground ,beetle #ac4 ,do4 ,ermine ,moth #ad4 ,do4 ,tiger ,moth #ae4 ,do4 ,blowfly #af4 ,do4 do4 section #ag4 ,do4 ,ichneumon #ah4 ,eye of ,butterfly1 ,atalanta #ai4 ,eyes1 ,bee #bj4 ,eye1 ,death's ,head ,moth #ba4 ,breathing-tube1 ,silkworm #bb4 ,eye1 ,heliophilus #bc4 ,do4 ,lobster #bd4 ,do4 ,aphis of ,geranium #be4 ,head1 ,parasite of ,tortoise #bf4 ,hind leg1 ,aphis of ,geranium #bg4 ,head1 ,gnat #bh4 8,paps0 of ,aphis #bi4 ,head1 ,sheep-tick #cj4 ,foot1 ,tipula ,illustration3 ,,vi4 ,the curiously elongated head of the scorpion-fly 7,panorpa71 seen at ,fig4 #g1 affords another example of the remarkable manner in which these organs are developed in different insects4 ,another elongated head1 belonging to the daddy long-legs1 is seen in ,plate ,,vi4 ,fig4 #bg1 and well shows the compound eyes1 the antenn1 and the palpi4 ,fig4 #b represents the coiled tongue of the ,atalanta butterfly2 it is composed of the maxill1 very greatly developed1 and appearing as if each had originally been flat1 and then rolled up so as to make about three-fourths of a tube4 ,a number of projections are seen towards the tip1 and one of these little bodies is shown on a larger scale at ,fig4 #c4 ,these curious organs have probably some connection with the sense of taste4 ,along the edges of the semi-tubes are arranged a number of very tiny hooks1 by means of which the insect can unite the edges at will4 ,fig4 #aa1 in the centre of the ,plate1 shows one of the most curious examples of insect structure1 the proboscis or trunk of the common bluebottle-fly4 ,the maxillary palpi covered with bristles are seen projecting at each side1 and upon the centre are three lancet-like appendages1 two small and one large1 which are used for perforating various substances on which the insect feeds4 ,the great double disc at the end is composed of the lower lip greatly developed1 and is filled with a most complex arrangement of sucking-tubes1 in order to enable it to fulfil its proper functions4 ,the numerous tubes which radiate towards the circumference are strengthened by a vast number of partial rings of strong filamentary substance1 like that which we have already seen in the breathing-tube of the silkworm4 ,some of these partial rings are seen on ,fig4 #ab1 a little above4 ,the mode in which the horny matter composing the rings is arranged upon the tubes is most wonderful1 and requires a tolerably high power to show it4 ,the fine hairs upon the proboscis itself afford most admirable practice for the young microscopist4 ,they should1 when properly lighted and focused1 be quite black and sharp4 ,any errors of manipulation will cause them to be 8fuzzy40 ,fig4 #e shows the tongue of the common cricket1 a most elegantly formed organ1 having a number of radiating bands covered with zigzag lines1 due to the triangular plates of strengthening substance with which they are furnished1 instead of the rings4 ,a portion more highly magnified is shown at ,fig4 #f1 exhibiting the manner in which the branches are arranged4 99 99 99 99 99 ,the legs of insects now claim our attention4 ,fig4 #i1 ,plate ,,vii41 shows the 8pro-leg0 of a caterpillar4 ,the pro-legs are situated on the hinder parts of the caterpillar1 and1 being set in pairs1 take a wonderfully firm hold of a branch or twig by pressure toward each other4 ,around the pro-legs are arranged a series of sharp hooks1 set with their points inwards1 for greater power in holding4 ,fig4 #aj represents one of the hooks more magnified4 ,fig4 #ae is the lower portion of the many-jointed legs of the long-legged spider 7,phalngium71 the whole structure looking very like the antenna of the cricket4 ,fig4 #ag is the leg of the glow-worm1 showing the single claw with which it is armed4 ,fig4 #bf shows the foot of the flea1 furnished with two simple claws4 ,fig4 #af is the foot of the ,trombdium1 a genus of parasitic creatures1 to which the well-known harvest-bug belongs4 ,fig4 #bf1 ,plate ,,vi41 shows the leg of the green ,aphis of the geranium1 exhibiting the double claw1 and the pad or cushion1 which probably serves the same purpose as the pads found upon the feet of many other insects4 ,fig4 #h is the lower portion of the leg of the ant1 showing the two claws and the curious pad in the centre1 by means of which the insect is able to walk upon slippery surfaces4 ,the ,tpula has a foot also furnished with a single pad 7see ,plate ,,vi4 ,fig4 #cj74 ,this organ is seen under a very high power to be covered with long hair-like appendages1 each having a little disc at the end1 and probably secreting some glutinous fluid which will enable the creature to hold on to perpendicular and smooth surfaces4 ,many of my readers will doubtless have noticed the common fly1 towards the end of autumn1 walking stiffly upon the walls1 and evidently detaching each foot with great difficulty1 age and infirmity having made the insect unable to lift its feet with the requisite force4 ,fig4 #ba is the foot of one of the ichneumon-flies 7,ophon71 the hairy fringe being apparently for the purpose of enabling it to hold firmly to the caterpillar in which it is depositing its eggs1 and which wriggles so violently under the infliction that it would soon throw its tormentor had not some special means been provided for the purpose of enabling the latter to keep its hold4 ,fig4 #bj is a beautiful example of a padded foot1 taken from the little red parasitic creature so plentifully found upon the dor or dung beetle 7,geotrpes71 and of which the afflicted insect is said to rid itself by lying on its back near an ant's nest1 and waiting until the ants carry off its tormentors4 ,fig4 #ah is the foot of the common yellow dung-fly 7plentiful in pasture lands71 having two claws and two pads2 and ,fig4 #ai shows the three pads and two claws found in the foot of the hornet-fly 7silus74 ,few microscopic objects call forth such general and deserved admiration as the fore-foot of the male water-beetle 7,dytiscus71 when properly prepared and mounted1 for which see ,fig4 #ac4 ,on examining this preparation under the microscope1 it is seen that three of the joints are greatly expanded1 and that the whole of their under surface is covered profusely with certain wonderful projections1 which are known to act as suckers4 ,one of them is exceedingly large1 and occupies a very considerable space1 its hairs radiating like the rays of the heraldic sun4 ,another is also large1 but scarcely half the diameter of the former1 and the remainder are small1 and mounted on the extremities of delicate foot-stalks1 looking something like wide-mouthed trumpets4 ,in the specimen from which the drawing was taken the smaller suckers are well shown1 as they protrude from the margin of the foot4 ,one of the larger suckers is seen more magnified on ,fig4 #ad4 ,plate ,,viii4 ,fig4 #a1 exemplifies the manner in which the muscles of insects do their work1 being well attached in the limbs to the central tendon1 and pulling 8with a will0 in one direction1 thus giving very great strength4 ,this leg is taken from the water boatman 7,notonecta71 and has been mounted in ,canada balsam4 ,on ,plate ,,vii4 ,fig4 #bi1 may be seen a curiously formed creature4 ,this is the larva of the tortoise beetle 7,cssida71 the skin having been flattened and mounted in ,canada balsam4 ,the spiracles are visible along the sides1 and at the end is seen a dark fork-like structure4 ,this is one of the peculiarities of this creature1 and is employed for the purpose of carrying the refuse of its food1 which is always piled upon its back1 and retained in its place by the forked spines1 aided probably by the numerous smaller spines that project from the side4 ,fig4 #cc shows part of the stomach and gastric teeth of the grasshopper4 ,this structure may be seen to perfection in the 8gizzard10 as it is called1 of the great green locust of ,england 7crida viridssima74 ,the organ looks like a sudden swelling of the sophagus1 and when slit longitudinally under water1 the teeth may be seen in rows set side by side1 and evidently having a great grinding power4 ,the common house cricket has a similar organ of remarkable beauty4 ,just above 7,fig4 #bg7 is the corresponding structure in the hive bee1 three of the teeth being shown separately at ,fig4 #bh4 99 99 99 99 99 ,we now cast a rapid glance at the wings of insects4 ,they have no analogy1 except in their use1 with the wings of birds1 as they are not modifications of existing limbs1 but entirely separate organs4 ,they consist of two membranes united at their edges1 and traversed and supported by sundry hollow branches or 8nervures10 which admit air1 and serve as useful guides to entomologists for separating the insects into their genera4 ,indeed1 the general character of the wings has long been employed as the means of dividing the insect race into their different orders1 as may be seen in any work on entomology4 ,the typical number of wings is four1 but it often happens that two are almost wholly absent1 or that the uppermost pair are thickened into a shelly kind of substance which renders them useless for flight2 while in many insects1 such as the ground beetles and others1 the upper wings become hardened into firm coverings for the body1 and the lower pair are shrivelled and useless4 ,fig4 #bb shows two of the wings of a humble bee1 together with their nervures1 and the peculiar system by which the upper and lower pair are united together at the will of the insect4 ,at the upper edge of the lower wing1 and nearly at its extremity1 may be seen a row of very tiny hooks1 shown on a larger scale at ,fig4 #be4 ,these hooklets hitch into the strengthened membrane of the upper wing1 which is seen immediately above them1 and so conjoin the two together4 ,the curious wing-hooks of the ,aphis may be seen on ,fig4 #bd1 very highly magnified4 ,fig4 #ca is the wing of the midge 7,psychda71 that odd little insect which is seen hopping and popping about on the windows of outhouses and similar localities1 and is so hard to catch4 ,the whole wing is plentifully covered with elongated scales1 and is a most lovely object under any power of the microscope4 ,these scales run along the nervures and edges of the wings1 and part of a nervure is shown more highly magnified at ,fig4 #cb4 ,at ,fig4 #bc is shown the wing of one of the hemipterous insects1 common along the banks of ditches and in shady lanes1 and known by the name of ,cxius4 ,it is remarkable for the numerous spots which stud the nervures1 one being always found at each forking1 and the others being very irregularly disposed4 ,fig4 #cj is one of the balancers or 8haltres0 of the house-fly4 ,these organs are found in all the two-winged insects1 and are evidently modifications of the second pair of wings4 ,they are covered with little vesicles1 and protected at their base by scales4 ,some writers suppose that the sense of smell resides in these organs4 ,whatever other purpose they may serve1 they clearly aid in the flight1 as1 if the insect be deprived of one or both of the balancers1 it has the greatest difficulty in steering itself through the air4 ,the wings of insects are mostly covered with hairs or scales1 several examples of which are given in ,plate ,,viii4 ,fig4 #d shows one of the scales of the ,adippe or fritillary butterfly1 exhibiting the double membrane--part of which has been torn away--and the beautiful lines of dots with which it is marked4 ,the structure of the scales is further shown by a torn specimen of tiger moth scale seen on ,fig4 #af4 ,on many scales these dots assume a 8watered0 aspect when the focus or illumination changes1 an example of which may be seen in ,fig4 #ae1 a scale of the peacock butterfly4 ,fig4 #aa is one of the ordinary scales of the azure blue butterfly1 and ,fig4 #aj shows one of the curious 8battledore0 scales of the same insect1 with its rows of distinct dottings4 ,fig4 #ad is one of the prettily tufted scales of the orange-tip butterfly1 and ,fig4 #h is the splendid branched scale of the death's-head moth4 ,fig4 #ai shows a scale of the sugar-runner 7,lepisma saccharna71 a little silvery creature with glistening skin1 and long bristles at the head and tail1 that is found running about cupboards1 window-sills1 and similar places4 ,it is not easy to catch with the fingers1 as it slips through them like oil2 but by holding a cover-glass in a pair of forceps1 and pressing it upon one of the little creatures1 a number of the scales may be caused to adhere to it1 and these should be mounted dry for examination4 ,the gnats also possess very pretty scales1 with the ribs projecting beyond the membrane4 ,,vii4 ,,fig4 #a4 ,tongue1 ,hive ,bee #b4 ,do4 ,tortoiseshell ,butterfly #c4 ,do4 do4 one of the barrel-shaped bodies #d4 ,head1 ,violet ,ground ,beetle 7,carabus7 #e4 ,tongue1 ,cricket #f4 ,do4 do4 #g4 ,head1 ,scorpion ,fly 7,panorpa7 #h4 ,leg1 ,ant #i4 ,proleg1 ,caterpillar #aj4 ,do4 do4 single hook #aa4 ,proboscis1 ,fly #ab4 ,do4 do4 8modified trachea0 #ac4 ,part of ,foreleg of ,water ,beetle 7,acilius7 #ad4 ,do4 large sucker #ae4 ,leg1 long-legged ,spider 7,phalangium7 #af4 ,do4 ,harvest-bug 7,trombidium7 #ag4 ,do4 ,glow-worm #ah4 ,do4 ,dung fly #ai4 ,do4 ,asilus #bj4 ,do4 ,acarus of ,dor-beetle #ba4 ,claws and ,pad1 ,ophion #bb4 ,wings1 ,humble ,bee #bc4 ,do4 #bd4 ,wing hooks1 hind wing of ,aphis #be4 ,wing hooks1 ,humble ,bee #bf4 ,foot1 ,flea #bg4 ,stomach and gastric teeth1 ,bee #bh4 ,three teeth of do4 #bi4 ,cast skin1 ,larva of ,tortoise ,beetle 7,cassida7 #cj4 ,balancer1 ,blow fly #ca4 ,wing1 ,midge 7,psychoda7 #cb4 ,do4 do4 part of a nervure with scales #cc4 ,stomach and gastric teeth1 ,grasshopper #cd4 ,spiracle1 ,wire-worm ,illustration3 ,,vii4 ,fig4 #ba is a scale from the common spring-tail 7,podra plmbea71 a little creature which is found plentifully in cellars and other damp places1 skipping about with great activity4 ,some flour scattered on a piece of paper is a sure trap for these little beings4 ,fig4 #c is one of the scales taken from the back of the celebrated diamond beetle1 showing the cause of the magnificent gem-like aspect of that insect4 ,we have in ,england many beetles of the same family--the weevils--which1 although much smaller1 are quite as splendid when exhibited under a microscope by reflected light4 ,the wing-case or 8elytron0 of a little green weevil1 very common in the hedges1 may be seen on ,plate ,,xii4 ,fig4 #aj4 ,the reader will observe that all these scales are furnished with little root-like appendages1 by means of which they are affixed to the insect4 ,fig4 #ac shows a portion of the wing of the azure blue butterfly1 from which nearly all the scales have been removed1 for the purpose of exhibiting the pits or depressions in which they had formerly been fastened1 and one or two of the scales are left still adherent to their places4 ,the scales are arranged in equal rows like the slates of a housetop1 as may be seen on ,fig4 #ah1 which represents part of the same wing1 to show the scales overlapping each other1 and the elegant form which they take near the edges of the wing1 so as to form a delicate fringe4 ,the long hair-like down which covers the legs and bodies of the moths and butterflies 7which are called ,lepidptera1 or scale-winged insects1 in consequence of this peculiarity71 is seen under the microscope to be composed of scales very much elongated1 as is shown in ,fig4 #ag1 a portion taken from the leg of a tiger moth4 99 99 99 99 99 ,the eggs of insects are all very beautiful1 and three of the most curious forms are given on ,plate ,,viii4 ,fig4 #b is the empty egg of the gad-fly1 as it appears when fastened to a hair of the horse4 ,fig4 #e represents the pretty ribbed egg of the common tortoise-shell butterfly2 and ,fig4 #g is the very beautiful egg of the very horrid bed-bug1 worthy of notice on account of the curious lid with which its extremity is closed1 by means of which the young larva creeps out as soon as it is hatched4 ,the feathers of birds1 and the fur of animals1 will furnish many examples of the eggs of parasites1 some of which are of extreme beauty4 ,the feather or hair may be mounted in a cell without disturbing the eggs1 which should1 however1 be heated sufficiently to kill the embryo if present4 ,fig4 #i shows the penetrating portions of the sting of the wasp4 ,the two barbed stings1 which seem to be the minute prototypes of the many-barbed spears of the ,south ,sea islanders1 are seen lying one at each side of their sheath1 and a single barb is drawn a little to the left on a very much larger scale4 ,it is by reason of these barbs that the sting is always left adhering to the wound1 and is generally drawn wholly out of the insect1 causing its death in a short while4 ,the sting is only found in female insects1 and is supposed to be analogous to the 8ovipositor0 of other insects1 i4e4 the instrument by which the eggs are deposited in their places4 ,fig4 #bj shows the curious egg-placing apparatus of one of the saw-flies4 ,the backs of these 8saws0 work in grooves1 and they work alternately1 so that the fly takes but a very short time in cutting a slit in the young bark of a tender shoot1 and laying her eggs in the slit4 ,when she has completed one of these channels1 she sets to work upon another1 and in the early spring the young branches of the gooseberry bushes may be seen plentifully covered with these grooves and the eggs4 ,when hatched1 black caterpillar-like grubs from the eggs issue1 and devastate the bushes sadly1 turning in process of time into blackish flies1 which are seen hovering in numbers over the gooseberries1 and may be killed by thousands4 99 99 99 99 99 ,the scales and hairs of other animals deserve great attention4 ,fig4 #bc is a single hair of the human beard1 as it often appears when tied in a knot--by ,queen ,mab and her fairies1 according to ,mercutio4 ,fig4 #bb is a portion of the same hair as it appears when splitting at its extremity4 ,the structure of the hair is not1 however1 so well seen in this object as in that represented on ,fig4 #bd1 which is a beautiful example of white human hair that once adorned the head of the victor of ,waterloo4 ,it formed one of a tiny lock given to me by a friend1 and is so admirable an example of human hair1 that ,i forthwith mounted it for the microscope4 ,in this hair the cells may be seen extending down its centre1 and the peculiar roughened surface produced by the flattened cells which are arranged around its circumference are also seen4 ,by steeping in caustic potash1 these scales can be separated1 but generally they lie along the hair in such a manner that if the hair be drawn through the fingers from base to point1 their projecting ends permit it to pass freely2 whilst if it be drawn in the reverse direction1 they cause it to feel very harsh to the touch4 ,in the sheep's wool 7,fig4 #cj7 this structure is much more developed1 and gives to the fibres the 8felting0 power that causes them to interlace so firmly with each other1 and enables cloth--when really made of wool--to be cut without unravelling4 ,fig4 #cg is the smooth hair of the badger2 and ,fig4 #cd is the curious hair of the red deer1 which looks as if it had been covered with a delicate net4 ,fig4 #bh is the soft1 grey1 wool-like hair of the rat2 and ,fig4 #bi is one of the larger hairs that protrude so plentifully1 and form the glistening brown coat of that animal4 ,fig4 #ch is the curiously knobbed hair of the long-eared bat1 the knobs being formed of protuberant scales that can easily be scraped off4 ,fig4 #ca shows a hair of the common mole2 and ,fig4 #cb is one of the long hairs of the rabbit4 ,fig4 #bg is a flat hair of the dormouse1 slightly twisted1 the difference in the breadth showing where the twist has taken place4 ,the hair of the mouse is beautifully ribbed1 so as to look like a ladder4 ,fig4 #bf is one of the very long hairs that so thickly clothe the tiger moth caterpillar2 and ,fig4 #be is a beautifully branched hair taken from the common humble bee4 ,all hairs should be examined by polarised light1 with a plate of selenite1 when most gorgeous colour effects may be obtained4 ,the four fibres mostly used in the manufacture of apparel are3 wool1 ,fig4 #cj1 which has already been described2 linen1 ,fig4 #ci2 cotton1 ,fig4 #dj2 and silk1 ,fig4 #da4 ,the structure of each is very well marked and easily made out with the microscope2 so that an adulterated article can readily be detected by a practised eye4 ,cotton is the most common adulteration of silk and linen fabrics1 and may at once be detected by its flat twisted fibre4 ,silk is always composed of two parallel threads1 each proceeding from one of the spinnerets of the caterpillar1 and it may be here remarked that if these threads are not quite parallel the silk is of bad quality4 ,silken fibre is always covered1 when new1 with a kind of varnish1 usually of a bright orange colour1 which gives the undressed 8floss0 silk its peculiar hue1 but which is soluble and easily washed away in the course of manufacture4 ,figs4 #ce and #cf are the small and large hairs of that magnificent creature1 the sea mouse 7,aphrodte aculeta71 whose covering1 although it lies in the mud1 glows with every hue of the rainbow1 and in a brilliant light is almost painfully dazzling to the eye4 ,,viii4 ,,fig4 #a4 ,boat-fly1 leg #b4 ,gadfly1 empty egg #c4 ,diamond ,beetle1 scale #d4 ,scale1 ,fritillary1 ,adippe #e4 ,egg1 ,tortoiseshell ,butterfly #f4 ,head and ,eyes1 ,zebra ,spider #g4 ,eyes1 ,bed-,bug #h4 ,scale1 ,death's-,head ,moth #i4 ,sting1 ,wasp #aj4 ,scale1 battledore1 ,azure blue #aa4 ,do4 ordinary scale #ab4 ,eye1 ,harvest ,spider #ac4 ,wing ,membrane1 ,azure ,blue #ad4 ,scale1 ,anthocera cardaminis #ae4 ,do4 ,peacock ,butterfly #af4 ,do4 ,tiger ,moth #ag4 ,do4 ,thigh of ,tiger ,moth #ah4 ,wing and ,scales1 ,azure ,blue #ai4 ,scale1 ,lepisma #bj4 ,saws1 ,sawfly #ba4 ,scale1 ,podura #bb4 ,hair1 ,black ,human #bc4 ,do4 ,human ,beard #bd4 ,do4 do4 aged #be4 ,do4 ,humble ,bee #bf4 ,do4 ,tiger ,moth1 ,larva #bg4 ,do4 ,dormouse #bh4 ,do4 ,rat #bi4 ,do4 do4 long hair #cj4 ,do4 ,sheep #ca4 ,do4 ,mole #cb4 ,do4 ,rabbit #cc4 ,scale1 ,greenbone ,pike #cd4 ,hair1 ,red ,deer #ce4 ,do4 fine1 ,sea ,mouse #cf4 ,do4 do4 large #cg4 ,do4 do4 ,badger #ch4 ,do4 do4 long-eared ,bat #ci4 ,fibre1 ,linen #dj4 ,do4 ,cotton #da4 ,do4 ,silk #db4 ,scale1 ,perch #dc4 ,do4 do4 ,illustration3 ,,viii4 ,the scales of some of the fishes are shown on ,plate ,,viii41 in order to exhibit their mode of growth by successive layers4 ,the scales are always enveloped in membranous sacs1 and in some cases1 as in the eel1 they do not project beyond the surface1 and require some little observation to detect them4 ,a scale of an eel is shown on ,plate ,,xi4 ,fig4 #ad1 and is a magnificent object under polarised light4 ,fig4 #cc is a scale of the greenbone pike2 and ,figs4 #db and #dc are scales of the perch1 showing the roots by which they are held in their places4 ,the roach1 dace1 bleak1 and many other similar fish have a beautiful silvery substance on the under surface of the scales1 which was greatly used in the manufacture of artificial pearls1 glass beads being thinly coated in the interior with the glittering substance1 and then filled in with wax4 ,a piece of sole-skin1 when preserved in ,canada balsam and placed under the microscope1 is a very beautiful object4 ,more examples of hairs1 and other processes from the skin1 together with the structure of the skin itself1 of bone1 of blood1 and the mode in which it circulates1 are given on ,plate ,x4 ,in all important points of their structure the feathers of birds are similar to the hairs of animals1 and are developed in a similar manner4 ,they are all composed of a quill portion1 in which the pith is contained1 and of a shaft1 which carries the vane1 together with its barbs4 ,the form of each of these portions varies much1 even in different parts of the same bird1 and the same feather has almost always two kinds of barbs2 one close and firm1 and the other loose1 floating1 and downy4 ,if a small feather be plucked from the breast or back of a sparrow or any other small bird1 the upper part of the feather is seen to be close and firm1 while the lower is loose and downy1 the upper part being evidently intended to lie closely on the body and keep out the wet1 while the lower portion affords a soft and warm protection to the skin4 ,fig4 #ab1 ,plate ,x41 shows the feather of a peacock1 wherein the barbs are very slightly fringed and lie quite loosely side by side4 ,fig4 #ah is part of the same structure1 in a duck's feather1 wherein are seen the curious hooks which enable each vane to take a firm hold of its neighbour1 the whole feather being thus rendered firm1 compact1 and capable of repelling water4 ,the reader will not fail to notice the remarkable analogy between these hooks and those which connect the wings of the bee4 ,fig4 #ag is a part of the shaft of a young feather taken from the canary1 given for the purpose of showing the form of the cells of which the pith is composed4 ,fig4 #bj is part of the down from a sparrow's feather1 showing its peculiar structure2 and ,fig4 #ba is a portion of one of the long drooping feathers of the cock's tail4 ,fig4 #ac exhibits a transverse section of one of the large hairs or spines from the hedgehog1 and shows the disposition of the firm1 horn-like exterior1 and the arrangement of the cells4 ,sections of various kinds of hair are interesting objects1 and are easily made by tying a bundle of them together1 soaking them in gum1 hardening in spirit1 and then cutting thin slices with a razor4 ,a little glycerine will dissolve the gum1 and the sections of hair will be well shown4 ,unless some such precaution be taken1 the elasticity of the hair will cause the tiny sections to fly in all directions1 and there will be no hope of recovering them4 ,several examples of the skin are also given4 ,fig4 #bg is a section through the skin of the human finger1 including the whole of one of the little ridges which are seen upon the extremity of every finger1 and half of two others4 ,the cuticle1 epidermis1 or scarf-skin1 as it is indifferently termed1 is formed of cells or scales1 much flattened and horny in the upper layers1 rounder and plumper below4 ,the true skin1 or 8cutis10 is fibrous in structure1 and lies immediately beneath1 the two together constituting the skin1 properly so called4 ,beneath lies a layer of tissue filled with fatty globules1 and containing the glands by which the perspiration is secreted4 ,one of the tubes or channels by which these glands are enabled to pour their contents to the outside of the body1 and1 if they be kept perfectly clean1 to disperse them into the air1 is seen running up the centre of the figure1 and terminating in a cup-shaped orifice on the surface of the cuticle4 ,on the palm of the hand very nearly three thousand of these ducts lie within the compass of a square inch1 and more than a thousand in every square inch of the arm and other portions of the body1 so that the multitude of these valuable organs may be well estimated1 together with the absolute necessity for keeping the skin perfectly clean in order to enjoy full health4 ,fig4 #a shows a specimen of epidermis taken from the skin of a frog1 exhibiting the flattened cells which constitute that structure1 and the oval or slightly elongated nuclei1 of which each cell has one4 ,in ,fig4 #cb1 a portion of a bat's wing1 the arrangement of the pigment is remarkably pretty4 ,immediately above1 at ,fig4 #ca1 is some of the pigment taken from the back of the human eye-ball4 ,the shape of the pigment cells is well shown4 ,similar specimens may easily be obtained from the back of a sheep's eye which has been hardened in spirit1 or from that of a boiled fish4 ,fig4 #cc shows the pigment in the shell of the prawn4 99 99 99 99 99 ,on various parts of animal structures1 such as the lining of internal cavities1 the interior of the mouth1 and other similar portions of the body1 the cells are developed into a special form1 which is called 8,epithlium10 and which corresponds to the epidermis of the exterior surface of the body4 ,the cells which form this substance are of different shapes1 according to their locality4 ,on the tongue1 for example 7for which see ,fig4 #aa71 they are flattened1 and exhibit their nucleus1 in which the nuclolus may be discovered with a little care4 ,cells of this kind are rounded1 as in the case just mentioned1 or angular1 and in either case they are termed squamous 7i4e41 scaly7 epithelium4 ,sometimes they are like a number of cylinders1 cones1 or pyramids1 ranged closely together1 and are then called cylindrical epithelium4 ,sometimes the free ends of cylindrical epithelium are furnished with a number of vibrating filaments or cilia1 and in this case the structure is called 8ciliated0 epithelium4 ,cylindrical epithelium may be found in the ducts of the glands which open into the intestines1 as well as in the glands that secrete tears2 and ciliated epithelium is seen largely in the windpipe1 the interior of the nose1 etc4 ,a specimen taken from the nose is seen at ,fig4 #ae4 ,a beautiful example of ciliated epithelium is to be found in the gills of the mussel4 ,a portion of one of the yellowish bands which lie along the edge of the shell on the opening side is carefully removed with sharp scissors1 and examined in the shell-liquor1 being protected from pressure by placing a piece of paper beneath each end of the cover-glass4 ,such a preparation is shown in ,plate ,,ix4 ,fig4 #ci1 but no drawing can give an idea of its wonderful beauty and interest4 ,the cilia will continue to move for a long time after removal from the shell4 99 99 99 99 99 ,bone in its various stages is figured on ,plate ,x4 ,fig4 #i is a good example of human bone1 and is a thin transverse section taken from the thigh4 ,when cut across1 bone exhibits a whitish structure filled with little dottings that become more numerous towards the centre1 and are almost invisible towards the circumference4 ,in the centre of the bone there is a cavity1 which contains marrow in the mammalia and air in the birds4 ,when placed under a microscope1 bone presents the appearance shown in the illustration4 ,the large aperture in the centre is one of innumerable tubes that run along the bone1 and serve to allow a passage to the vessels which convey blood from one part of the bone to another4 ,they are technically called ,haversian canals1 and if a longitudinal section be made they will be found running tolerably parallel1 and communicating freely with each other4 ,around each ,haversian canal may be seen a number of little black spots with lines radiating in all directions1 and looking something like flattened insects4 ,these are termed bone-cells or 8lacn10 and the little black lines are called 8canalculi40 ,in the living state they contain cells which are concerned in the growth of the bone1 and these may be made evident by softening fresh bone with acid1 cutting sections of it1 and staining4 ,when viewed by transmitted light the lacun and canaliculi are black2 but when seen by dark-field illumination the ,haversian canals become black1 and the lacun are white4 ,as these canaliculi exist equally in every direction1 it is impossible to make a section of bone without cutting myriads of them across2 and when a high power is employed they look like little dots scattered over the surface4 ,a very pretty object can be made of the bone taken from a young animal which has been fed with madder1 as the colour gets into the bone and settles chiefly round the ,haversian canal4 ,a young pig is a very good subject1 so is a rabbit4 ,fig4 #af is a similar section cut from the leg-bone of an ostrich4 ,the development of bone is beautifully shown in ,fig4 #cj1 a delicate slice taken from a pig's rib4 ,above may be seen the gristle or cartilage1 with the numerous rows of cells2 below is the formed bone1 with one of the ,haversian canals and its contents2 while between the two may be seen the cartilage-cells gathering together and arranging themselves into form4 ,the cartilage-cells are well shown in ,fig4 #bh1 which is a portion of the cup which had contained the eye of a haddock4 ,the horn-like substances at the end of our fingers1 which we call the nails1 are composed of innumerable flattened cells4 ,these cells are generally so fused together as to be quite indistinguishable even with a microscope1 but can be rendered visible by soaking a section of nail in liquor potass1 which causes the cells to swell up and resume to a degree their original rounded form4 ,it is worthy of remark that the animal form is built up of cells1 as is the case with the vegetables1 although the cells are not so variable in shape4 ,they generally may be found to contain well-marked nuclei1 two or more of the latter being often found within a single cell1 and in many cases the tiny nucleoli are also visible4 ,good examples of these cells may be obtained from the yolk of an egg1 and by careful management they may be traced throughout every part of the animal form4 ,the teeth have many of the constituents of bone1 and in some of their parts are made after precisely the same fashion4 ,when cut1 the teeth are seen to consist of a hard substance1 called enamel1 which coats their upper surfaces1 of dentine1 or ivory1 within the enamel1 and of 8cement10 which surrounds the fangs4 ,in ,fig4 #bf1 ,plate ,x41 which is a longitudinal section of the human 8eye0 tooth1 is seen the ivory occupying the greater part of the tooth1 coated by the enamel at the top and the cement at the bottom4 ,in the centre of each tooth there is a cavity1 which is plentifully filled with a pulpy substance by which the tooth is nourished1 and which conveys the nerves which endow it with sensation4 ,a traverse section of the same tooth is seen in ,fig4 #be4 ,the enamel is made of little elongated prisms1 all pointing to the centre of the tooth4 ,when viewed transversely1 their ends are of a somewhat hexagonal shape1 something like an irregular honeycomb4 ,the dentine is composed of a substance pierced with myriads of minute tubes4 ,they require a rather high power--say #cjj diameters--to show them properly4 ,the cement is found at the root of the fangs1 and is best shown in the tooth of an aged individual1 when it assumes very clearly the character of bone4 ,sections may be made by sawing a slice in the required direction1 polishing one side1 and cementing it with old ,canada balsam to a slide4 ,it may then be filed down to nearly the required thinness1 finished by carefully rubbing with a hone1 and polished with buff leather4 ,canada balsam may then be dropped upon it1 and a glass cover pressed firmly down4 ,sections of young bone form magnificent objects for the polariser4 ,fig4 #bi is a section cut from one of the palate teeth of the ray 7,myliobtes74 ,a rather important element in the structure of animals is the 8elastic ligament10 which is found in the back of the neck and other parts of the body1 especially about the spine4 ,it is made of a vast number of fibres of variable shape and length1 branching and communicating1 arranged generally in bundles1 and remarkable for containing very few vessels1 and no nerves at all4 ,at ,fig4 #ad may be seen an example of elastic ligament1 popularly called 8paxwax10 taken from the neck of a sheep4 ,the white fibrous tissue by which all the parts of the body are bound together is seen at ,fig4 #aj2 and at ,fig4 #aa is a beautiful example of the 8ultimate fibres0 of the crystalline lens of a sturgeon's eye4 ,the muscles of animals are of two kinds1 the one termed the striped1 and the other the unstriped4 ,of these1 the latter belongs to organs which work independently of will1 such as the stomach1 etc41 while the former belongs to those portions of the body which are subject to voluntary motion1 such as the arm and the leg4 ,the unstriped muscle is very simple1 consisting merely of long spindle-shaped cells1 but the striped or voluntary muscle is of more complex construction4 ,every voluntary muscle consists of myriads of tiny fibres1 bound together in little bundles1 enveloped in a kind of sheath4 ,fig4 #bd is an example of this muscular fibre1 taken from beef4 ,when soaked in spirit1 it often splits into a number of discs1 the edges of which are marked by the transverse lines4 ,a fibre of nerve is drawn at ,fig4 #bc1 and is given for the purpose of showing the manner in which the nerve is contained in and protected by its sheath1 just like a telegraph-wire in its coverings4 ,just above is a transverse section of the same fibre1 showing the same arrangement from another point of view1 and also illustrating the curious phenomenon1 that when nerve-fibres are treated with carmine the centre takes up the colouring matter1 while the sheath remains white as before4 ,the best way of studying nerves is to decapitate a frog1 and cut off a piece of one of the nerves1 which1 like fine silk threads1 come out between the joints of the spine inside the abdomen4 ,by careful teasing out it is easy to obtain preparations showing all the above points1 and1 in addition1 the folding-in of the internal sheath which correspond to the insulators of a telegraph-line4 ,the blood of animals is analogous in its office to the sap of plants1 but differs greatly from it under the microscope4 ,in sap there seem to be no microscopic characters1 except that when a branch is cut1 as in the vine1 the flowing sap may contain certain substances formed in the wounded cells1 such as chlorophyll1 starch1 and raphides2 but the blood is known to be an exceedingly complex substance both in a microscopic and a chemical point of view4 ,when a little fresh blood is placed under the microscope1 it is seen to consist of a colourless fluid filled with numerous little bodies1 commonly called 8blood-globules10 varying very greatly in size and shape1 according to the animal from which they were taken4 ,those of the reptiles are very large1 as may be seen at ,fig4 #d1 ,plate ,x41 which represents a blood corpuscle of the ,proteus4 ,in this curious reptile the globules are so large that they may be distinguished during its life by means of a common pocket lens4 ,in the vertebrated animals these corpuscles are red1 and give to the blood its peculiar tint4 ,they are accompanied by certain colourless corpuscles1 spherical in form1 which are sometimes1 as in man1 larger than the red globules1 and in others1 as in the siren and the newt1 considerably smaller4 ,the general view of the red corpuscles has sufficient character to enable the practised observer to name the class of animal from which it was taken1 and in some cases they are so distinctive that even the genus can be ascertained with tolerable certainty4 ,in point of size1 the reptiles have the largest and the mammalia the smallest1 those of the ,proteus and the musk-deer being perhaps the most decidedly opposed to each other in this respect4 ,,ix4 ,,fig4 #a4 ,amba diffluens #b4 ,arcella #c4 ,sun animalcule #d4 ,miliolina #e4 ,paramcium #f4 ,chilodon subdividing #g4 ,melicerta ringens #h4 ,spicula of ,sponge1 ,grantia #i4 ,noctiluca miliaris #aj4 ,rotifer vulgaris #aa4 ,do4 jaws #ab4 ,sponge animalcule #ac4 ,sertularia operculata #ad4 ,sponge1 ,grantia #ae4 ,sertularia operculata1 with ovicells #af4 ,actinia1 showing weapons #ag4 ,do4 base of weapon more magnified #ah4 ,sponge granule1 ciliated #ai4 ,anguinaria anguina #bj4 ,spicules of sponge from ,oyster ,shell #ba4 ,head of ,snake-headed ,zoophyte #bb4 ,bugula avicularia #bc4 ,polyzon1 ,eretea #bd4 ,do4 ,notamia #be4 ,zoea1 ,young of ,crab #bf4 ,hydra tuba #bg4 ,medusa1 cast off from above #bh4 ,naked-eyed ,medusa1 ,thaumantias #bi4 ,compound ,eye1 ,medusa #cj4 ,larva1 ,snake ,star #ca4 ,water ,flea #cb4 ,serpula1 ,pushing ,pole #cc4 ,comatula1 early stage of ,starfish #cd4 ,carbonate of ,lime1 artificial #ce4 ,sea ,urchin1 transverse section of spine #cf4 ,serpula1 bundle of spears #cg4 ,sun-star1 part of skin #ch4 ,oyster shell in different stages #ci4 ,cilia on mussel ,illustration3 ,,ix4 ,in shape1 those of the mammalia are circular discs1 mostly with a concave centre1 though the camel has oval ones2 those of the birds are more or less oval and convex2 those of the reptiles are decidedly oval1 very thin1 and have the nucleus projecting2 and those of the fishes are oval and mostly convex4 ,during the process of coagulation the blood corpuscles run together into a series of rows1 just as if a heap of pence had been piled on each other and then pushed down1 so that each penny overlaps its next neighbour4 ,these objects are illustrated by six examples on ,plate ,x4 ,fig4 #b is human blood1 showing one of the white corpuscles2 ,fig4 #c is the blood of the pigeon2 ,fig4 #d1 of the ,proteus angunus2 ,fig4 #e1 of the tortoise2 ,fig4 #f1 of the frog1 showing the projecting nucleus2 and ,fig4 #g1 of the roach4 ,the blood possesses many curious properties1 which cannot be described in these few and simple pages4 ,in the centre of ,plate ,x4 is a large circular figure representing the membrane of a frog's foot as seen through the microscope1 and exhibiting the circulation of the blood4 ,the mode of arranging the foot so as to exhibit the object without hurting the frog is simple enough4 ,take an oblong slip of wood1--my own was made in five minutes out of the top of a cigar-box1--bore a hole about an inch in diameter near one end1 and cut a number of little slits all round the edge of the wooden slip4 ,then get a small linen bag1 put the frog into it1 and dip him into water to keep him comfortable4 ,when he is wanted1 pull one of his hind feet out of the bag1 draw the neck tight enough to prevent him from pulling his foot back again1 but not sufficiently tight to stop the circulation4 ,have a tape fastened to the end of the bag1 and tie it down to the wooden slide4 ,then fasten a thread to each of his toes1 bring the foot well over the centre of the hole1 stretch the toes well apart1 and keep them in their places by hitching the threads into the notches on the edge of the wooden strip4 ,perhaps an easier plan is to secure the threads by drops of sealing-wax when in the desired position4 ,push a glass slide carefully between the foot and the wood1 so as to let the membrane rest upon the glass1 and be careful to keep it well wetted4 ,if the frog kick1 as he will most likely do1 pass a thin tape over the middle of the leg1 and tie him gently down to the slide4 ,bring the glass into focus1 and the foot will present the appearance so well depicted in the engraving4 ,the veins and arteries are seen spreading over the whole of the membrane1 the larger arteries being often accompanied by a nerve1 as seen in the illustration4 ,through all these channels the blood continually pours with a rather irregular motion1 caused most probably by the peculiar position of the reptile4 ,it is a most wonderful sight1 of which the observer is never tired1 and which seems almost more interesting every time that it is beheld4 ,the corpuscles go pushing and jostling one another in the oddest fashion1 just like a ,british crowd entering an exhibition1 each one seeming to be elbowing its way to the best place4 ,to see them turning the corners is very amusing1 for they always seem as if they never could get round the smaller vessels1 and yet invariably accomplish the task with perfect ease1 turning about and steering themselves as if possessed of volition1 and insinuating their ends when they could not pass crosswise4 ,by putting various substances1 such as spirit or salt1 upon the foot1 the rapidity of the circulation at the spot can be greatly increased or reduced at will1 or even stopped altogether for a while1 and the phenomenon of inflammation and its gradual natural cure be beautifully illustrated4 ,the numerous black spots upon the surface are pigment-cells4 ,the tails of young fish also afford excellent objects under the microscope1 as the circulation can be seen nearly as well as in the frog's foot4 ,the gills of tadpoles can also be arranged upon the stage with a little care1 and the same organs in the young of the common newt will also exhibit the circulation in a favourable manner4 ,the frog1 however1 is perhaps the best1 as it can be arranged on the 8frog-plate0 without difficulty1 and the creature may be kept for months by placing it in a cool1 damp spot1 and feeding it with flies1 little slugs1 and similar creatures4 ,,chapter ,,viii ,pond-,life--,apparatus and ,instructions for ,collecting ,objects--,methods of ,examination--,sponge--,infusoria4 ,of all departments of microscopic research the most fascinating and the most popular is that which deals with what is known by the generic name of 8pond-life40 ,the minute forms of the animal creation included in this term are of such exquisite beauty1 and allow the processes of their life-history to be followed with such facility1 from the cradle 7when they have one7 to the grave 7which is very often the body of another1 larger1 organism71 that there is none which has attracted more observers4 ,indeed1 the first application of the microscope1 by ,leeuwenhoek1 early in the seventeenth century1 was to the observation of these forms of life4 ,x4 ,,fig4 #a4 ,skin1 ,frog #b4 ,blood1 ,human #c4 ,do4 ,pigeon #d4 ,do4 ,proteus #e4 ,do4 ,tortoise #f4 ,do4 ,frog #g4 ,do4 ,fish #h4 ,human nail #i4 ,bone1 ,human #aj4 ,white fibrous tissue #aa4 ,epithelial cells from tongue #ab4 ,feather1 ,peacock #ac4 ,spine1 ,hedgehog1 transverse section #ad4 ,pax-wax #ae4 ,epithelial cells from nose #af4 ,bone1 ,ostrich #ag4 ,feather1 ,shaft of ,canary's #ah4 ,do4 ,wild ,duck #ai4 ,circulation of blood1 ,frog's foot #bj4 ,feather1 ,sparrow #ba4 ,do4 ,cock's tail #bb4 ,fibre1 crystalline lens of fish #bc4 ,nerve #bd4 ,muscle1 ,meat #be4 ,tooth1 transverse section #bf4 ,do4 ,longitudinal section #bg4 ,sweat duct #bh4 ,eye of ,haddock #bi4 ,myliobates1 palate #cj4 ,gristle1 ,pig #ca4 ,pigment1 ,human eye #cb4 ,do4 ,wing of ,bat #cc4 ,do4 ,shell of ,prawn ,illustration3 ,x4 ,a few words may be said1 in the first place1 as to the outfit4 ,a very useful part of it is a walking-stick1 to which can be attached either a net for capturing the larger forms of life1 or a hook for collecting the weeds1 to which many forms of great interest and beauty are attached 7,fig4 #ae74 ,the stick is telescopic1 and can also have attached to it a bottle1 which1 put into the water at any desired spot1--say1 amongst a clump of weeds1 or near the bottom1 upside down1 and then suddenly reversed1--will bring away samples of the inhabitants of the neighbourhood4 ,when these are sparsely distributed through the water1 the latter may be concentrated by the use of a bottle round the neck of which is firmly tied a coarse calico bag1 funnel-shaped1 and supported by a wire ring1 somewhat as shown in the illustration4 ,muslin is1 however1 too coarse for many organisms4 ,this net is immersed in the water so that the ring is just above the surface1 and one bottleful after another poured through4 ,the water strains off1 the organisms are left behind4 ,the immersion is necessary to reduce the pressure to which delicate organisms would otherwise be subjected4 ,when the bottle is full1 or sufficiently concentrated as to its contents1 the latter are poured into one of the ordinary collecting-bottles1 of which half a dozen at least should always be taken4 ,illustration3 ,fig4 #ae4 ,on reaching home1 and as often as possible on the way1 the corks should be removed1 as these organisms soon use up the air in the water4 ,for examination a glass trough of considerable size1 say three inches in length1 half an inch in depth1 and two inches in height1 should be half filled with the water1 and examined with the pocket magnifier4 ,with a little practice it will be found easy to take up not only the larger organisms1 but even very minute ones1 with one of the dipping-tubes with a long tapering point already referred to4 ,the organism1 when 8spotted10 is followed by eye and tube1 the finger being held over the mouth of the latter1 and at the critical moment the finger is removed1 and the organism swept into the tube by the in-rushing water4 ,now wipe off the excess with a clean handkerchief1 8spot0 the organism in the tube again1 and carefully absorb the superfluous water with a piece of blotting paper2 and finally1 gently but sharply blow the remainder on to the plate of the live-box1 put on the cover1 and examine with a one-inch power4 ,if1 as often happens1 the organism sticks to the side of the tube1 a little more water must be drawn in1 and the process repeated4 ,the use of the cotton-wool trap spoken of previously will often be very helpful in the examination of actively moving organisms4 ,in the case of weeds1 a small portion should be placed in the trough and carefully examined from end to end1 first with the pocket lens and then with the one-inch power4 ,let us now consider the objects most likely to be met with4 ,a piece of stick may be coated with a white layer1 feeling rough to the touch1 and full of small holes4 ,the chances are that this will be a piece of fresh-water sponge1 ,spongilla fluviatlis1 and by dark-field illumination particles may be seen to enter at some orifices and be ejected at others4 ,with a very high power and a very thin section1 properly prepared1 these holes will be seen to be the mouths of channels which are lined by the most delicate organisms possible1 each having a minute body crowned with a tiny crystal cup1 in the middle of which is a long cilium1 or flagellum1 as it is here called 7,plate ,,xiii4 ,fig4 #a74 ,the currents are produced by the combined action of these flagella4 ,in point of fact1 the sponge is a colony of minute animals working harmoniously for the common good4 ,if the specimen be found in winter the sponge will be full of tiny balls1 the 8gemmules0 of the next season's growth4 ,the roughness is due to the flinty spicules1 which are at once the scaffolding and the protection of the sponge1 and by boiling the sponge in a mixture of nitric acid and water 7half and half7 these spicules will be set free1 and may be washed1 allowed to settle1 washed again1 dried1 and mounted in balsam4 ,the gemmules are coated by very beautiful spicules1 consisting of two wheels connected by a rod4 ,these may be treated in the same way4 ,the life-history of the common sponge is as yet but imperfectly known4 ,perhaps the lowest form of life is the ,amba1 shown in ,plate ,,ix4 ,fig4 #a1 a mere lump of jelly1 which flows along1 and when it comes into contact with any likely subject for digestion flows round it1 encloses it1 absorbs what it can from it1 and leaves it behind4 ,a near relative of the ,amba is the ,arcella 7,fig4 #b71 which is simply an ,amba with a shell4 ,being unable to swim1 these organisms are naturally to be most often found at the bottom of the collecting bottle1 and it is always advisable to take up a portion of the dbris with a dipping tube1 which is then held upright on a slide with the finger upon it until the dirt settles on to the slide1 when it is removed1 a cover-glass put upon the dirt1 and a quarter-inch power used for examination4 ,many forms will be discovered in this way which would otherwise escape observation4 ,another curious organism1 of great size 7comparatively7 and extreme beauty1 is the sun animalcule 7,actnophrys71 which has a round body and long tentacles 7,fig4 #c71 to which free-swimming organisms adhere1 and by the combined action of the neighbouring ones are drawn to the body and received into it2 one cannot say swallowed4 ,fig4 #f1 ,plate ,,ix41 shows the curious arithmetical process whereby the ,infusoria multiply by division1 a groove appearing at one point1 rapidly deepening1 and finally separating the animal completely into two4 ,the species is the ,chlodon1 a flattened creature1 ciliated all over1 having a set of teeth arranged in the form of a tube1 and at its fore-part a kind of membranous lip4 ,a similar phenomenon1 in an earlier stage1 is shown in ,fig4 #bf1 ,plate ,,xiii41 the organism in this case being ,eupltes4 ,it has been said that sponges are colonies of extremely minute organisms1 each furnished with a membranous collar or funnel1 the whole looking like an exquisite wine-glass without a foot4 ,these organisms are not always grouped in colonies1 however4 ,many are free-growing1 and may be found attached to the stems of water-plants1 but they are extremely minute1 and will hardly be noticed until the microscopist has acquired considerable experience1 nor even then--with such an instrument as we have postulated--will he see more than a tiny pear1 with a straight line1 the margin of the cup1 on each side of its summit4 ,the flagellum will be quite invisible4 ,some similar organisms may1 nevertheless1 be found which1 though still minute1 are within the range of a properly managed quarter-inch objective4 ,such an one1 of extreme beauty1 is the ,dinobron shown in ,plate ,,xiii4 ,fig4 #c4 ,each 8zoid10 as the separate animals are called1 among the ,infusoria1 or each generation of zoids1 stands upon its parent and has two flagella4 ,when alarmed1 the zoid sinks to the bottom of its cell1 and withdraws its flagella4 ,in ,fig4 #b 7,euglna7 we have a similar zoid1 but of far greater size1 and free-swimming4 ,it is a very common object1 and possesses a red eye-speck close to the 8contractile vesicle40 ,all ,infusoria have the latter1 some a great number1 as in ,fig4 #i4 ,the vesicle contracts at regular intervals1 and is then simply blotted out1 but reforms in the same place1 so that it is probably the heart or the urinary bladder of these minute animals4 ,the lovely rosette shown in ,fig4 #d is the ,synura1 a spherical colony of zoids1 each of which has two flagella1 and is in addition clothed with rows of cilia4 ,a beautiful sight it is to watch these colonies rolling through the field of view4 ,not uncommon1 especially in brackish water1 is the ,peridinium 7,fig4 #e71 with its plate armour1 long flagellum1 and girdle of cilia4 ,a gigantic species of the same family is common in sea-water1 and will be easily recognised by its body1 not much larger than that of ,peridinium1 being furnished with three long arms1 curiously bent4 ,it is called ,ceratium1 and is sometimes present in such abundance as to thicken the water1 near the surface of which it swims4 ,we now come to a class of ,infusoria which is characterised by the possession of a complete covering of cilia1 arranged in rows all over the body4 ,the number of these is enormous2 we can only glance at a few types1 by mastering which the observer will1 at all events1 know whereabouts he is4 ,the first we will take is the ,coleps 7,fig4 #f71 a very common kind1 whose body is marked by a series of geometrical lines1 so that the organism looks very much like an elongated geographical globe4 ,these markings are on the tunic1 which is of a brownish colour4 ,very different is the ,trachelocerca 7,fig4 #g71 with its long flexible neck1 which is in constant movement from side to side as the creature swims along4 ,as seen in the figure1 the neck is clear and the head has a fringe of longer cilia4 ,the ,trachelius 7,fig4 #h7 is perhaps the largest of all the ,infusoria1 being readily visible to even an inexperienced eye4 ,its body is richly furnished with contractile vesicles1 and the protoplasm is curiously reticulated4 ,we may here remark that the ,trachelius is especially prompt in doing what most of these organisms do when put under pressure in a live-box1 namely1 in performing a kind of harakiri4 ,the outline first becomes irregular1 then the body rapidly swells and finally comes to pieces1 the fragments dancing mockingly away under the influence of their still-moving cilia4 ,the remedy is to use the cotton-wool trap and the lightest possible pressure4 ,a very elegant organism is shown in the bottom right-hand corner of the ,plate 7,fig4 #be74 ,it is the ,loxophyllum1 and has a strongly marked contractile vesicle4 ,another large form is ,amphileptus 7,fig4 #i71 already referred to as having a large number of contractile vesicles arranged in a regular row2 and more massive still is ,bursaria 7,fig4 #aj71 a very curious organism1 very much like a purse indeed1 and possessing a wonderful arrangement of cilia inside the funnel4 ,these are arranged like a ladder1 a series of rows of short stiff cilia1 which move at short intervals in unison1 and tend to sweep down into the cavity any small particles of food4 ,this arrangement is here described for the first time1 and appears to be quite unlike anything else among the ,infusoria4 ,not unlike ,bursaria1 but having no ladder1 and being furnished with a delicate membranous pouch in front of the slit of the purse1 is ,condylostoma1 which we shrewdly suspect to be the young form of ,bursaria4 ,this is a point which requires elucidation4 ,one of the most beautiful of all these forms is shown in ,fig4 #aa1 ,folliculina1 a type of a large group characterised by the possession of a transparent case1 of extremely elegant form1 within which the animal retreats on the slightest alarm4 ,fearless and independent1 as becomes its size1 is the trumpet-shaped ,stentor 7,fig4 #ab71 which may easily be seen when present1 as it is in almost every good gathering of water-weed4 ,the particular form drawn 7,s4 ,mlleri7 does not make a case1 but many members of the genus do1 and it is very common to see a stem almost covered with them4 ,such a sight1 once seen under dark-field illumination1 will never be forgotten4 ,the method of multiplication of the ,stentors 7by division7 is extremely easy to watch1 and very instructive4 ,a curious organism is ,trichodina 7,fig4 #ac71 which1 though a free-swimmer1 is always parasitic upon the body of some higher animal4 ,we have found it sometimes upon ,hydra1 and always in hundreds upon the stickleback4 ,the next group of ,infusoria is distinguished by the body's being only ciliated at particular points1 usually round the mouth1 or what acts as such4 ,the first form is ,vorticella 7,fig4 #ad71 a beautiful vase-like creature upon a stem4 ,down the stem runs a muscular fibre1 and on the least shock the fibre contracts and draws the stem into a beautiful spiral1 whilst the cilia are drawn in1 and the zoid assumes the appearance of a ball at the end of a watch-spring4 ,an exquisite sight is a colony of ,vorticell1 for these actions are always going on1 as1 for example1 when one member of the family touches another1 which is quite sufficient to provoke the contraction4 ,,xi4 ,,polarized ,,light4 ,,fig4 #a4 ,carbonate of ,lime #b4 ,starfish #c4 ,thistle down #d4 ,starch1 ,wheat #e4 ,do4 ,potato #f4 ,prawn-shell #g4 ,starch1 8,tous les mois0 #h4 ,bone1 cancellous #i4 ,gun-cotton #aj4 ,cow's hair #aa4 ,hoof1 donkey1 longitudinal #ab4 ,do4 transverse #ac4 ,nitre1 ,crystals #ad4 ,scale1 ,eel #ae4 ,wing1 ,water-,boatman #af4 ,chlorate of ,potash1 ,crystals #ag4 ,cellularia reptans #ah4 ,star-shaped hair1 ,stalk of ,yellow ,water-,lily #ai4 ,teeth1 ,palate of ,whelk #bj4 ,zoophyte1 ,bowerbankia #ba4 ,raphides1 i4e4 crystalline formations in vegetable cells1 ,bulb of ,hyacinth #bb4 ,do4 ,rhubarb #bc4 ,sulphate of ,magnesia1 ,crystals #bd4 ,bone1 ,skate #be4 ,cherrystone1 transverse section #bf4 ,sugar1 ,crystals in honey #bg4 ,tendon1 ,ox #bh4 ,calcareous plates4 ,tooth of ,echinus ,illustration3 ,,xi4 ,many compound tree-like forms of ,vorticella are known1 one of which1 ,carchesium 7,fig4 #ae71 may serve as a type of all4 ,in the case of this organism1 the colony contracts in sections on a moderate shock2 in the second1 ,zoothamnium1 as a whole2 whilst in ,epistylis the stalks are rigid1 and the individuals contract singly4 ,when the shock is violent1 the appearance presented by the two former is that shown in ,fig4 #af4 ,in all three cases the colonies are usually so large that they are visible as trees to the naked eye1 and some members of the group are extremely common4 ,moreover1 they are often parasitic1 as1 for example1 upon ,cyclops1 which is frequently loaded with them4 ,another compound form is ,ophrydium1 a colony of which 7not unusually large7 is shown of the natural size in ,fig4 #ah1 with a single zoid1 magnified1 by the side of it1 in ,fig4 #ai4 ,lastly1 we have an exquisite group of organisms related to ,vorticella1 but possessing a transparent envelope1 the forms of which are most varied1 but always graceful4 ,vaginicola 7,fig4 #ag7 is a good example of this1 and ,cothurnia 7,fig4 #bj7 still more so4 ,many of these organisms1 too1 are furnished with a plate1 attached either to the head or to the body1 which plate1 when they withdraw into their cases1 closes the latter perfectly1 as in the case of the exquisite ,pyxicola 7,fig4 #ba74 ,a very interesting but singularly obtrusive organism is the ,stylonychia 7,figs4 #bb1 #bc74 ,how often has it happened to us to have an interesting object nicely in the field of view1 and then to have it knocked out of sight by the blundering incursion of this burly fellow1 who runs so rapidly by means of his 8styles0 that he gives nothing time to get out of the way4 ,he is of interest to us1 however1 as the representative of a class in which the body is not ciliated1 or very partially and slightly so1 usually round the mouth4 ,we have frequently found ,stylonychia1 in company with ,vorticella and ,paramcium 7,plate ,,ix4 ,fig4 #f71 in the water in which flowers have been standing for a few days2 sometimes the numbers are so great as to make the water quite milky4 ,one more form must conclude this short sketch of the great ,infusorial family4 ,it is the ,acineta 7,fig4 #bd71 which1 attached by its foot-stalk1 and devoid of cilia1 patiently waits1 with outspread arms1 to receive and embrace smaller members of the family as they dance merrily about4 ,alas6 its embrace is as fatal as that of the image of the ,virgin which bore beneath its robe spikes and daggers1 for the victim struggles vainly to escape1 and the nourishment from its body is rapidly absorbed4 ,and here we take our leave of a group which1 simple as is the construction of the animals which it includes 7for every one1 great and small alike1 is composed of a single cell71 is yet full of beauty and interest4 ,he who wishes to pursue the matter further will find in ,saville ,kent's ,manual of the ,infusoria a perfect mine of information1 to which we gladly acknowledge our indebtedness1 both now and in time past4 ,,chapter ,,ix ,fresh-water ,worms--,planarians--,hydra--,polyzoa--, rotifers--,chtonotus-- ,water-,bears4 ,the fresh-water worms form a large and well-defined group1 and a few words regarding them may be useful4 ,they are very common1 and very difficult to find information about1 most of the work relating to them having been done in ,germany4 ,at the same time1 they are so highly organised and so transparent that the process of their life-history may be easily followed4 ,one large group has the peculiarity of multiplying by division1 the last joints or segments being devoted to the formation of the new individual4 ,at one time of the year the ordinary sexual process of reproduction takes the place of this method1 and each worm is then surrounded by a belt such as may be seen in the common earthworm under similar conditions4 ,further information on this subject is greatly needed4 ,the type is the common ,nas1 which has a body of thirty segments or more1 two eye-specks on the head1 and a double row of bristles along the back2 whilst below1 each segment carries strong hooked bristles1 nearly buried in the body1 by means of which the worm crawls4 ,inside the mouth is a large proboscis1 which can be protruded1 and this leads into a stomach which is merely an enlargement of the intestine which succeeds it4 ,the circulation of the blood 7which is colourless7 can be easily watched4 ,it begins at the tail with a contraction of the dorsal vessel1 passes up to the head1 and then down below the intestine to the tail again4 ,the intestine is ciliated inside1 and it is by a current of water carried into the intestine by these cilia that the blood is arated4 ,in the next genus1 ,dero1 this is clearly seen1 for the tail 7,plate ,,xiv4 ,fig4 #a7 is opened out into a wide shield1 from which rise four1 six1 or even eight finger-like processes4 ,these parts are all ciliated1 and contain a network of blood-vessels4 ,the worm lives in a case which it builds in the mud1 and the way to find it is to put some of the mud into a glass beaker with water1 and allow it to stand4 ,if there be members of this family in it1 their tails will be seen protruding above the water4 ,pour out the mud sharply1 fill up with water1 and allow the dirt to subside1 and the worms may then be made to leave their cases by pressure by a camel hair pencil on the lower end of the tube1 and may be caught with the dipping tube and placed in the live-box4 ,they have no eyes1 otherwise the general outline of the body closely resembles that of ,nas4 ,slavna 7,fig4 #b7 has a row of touch-organs1 like pimples1 round each segment1 and is a dirty looking creature1 with an inordinately long first pair of bristles1 but this reaches its acme in ,pristina 7,fig4 #c7 7sometimes1 though wrongly1 called ,stylaria7 parasita1 which has three long sets of bristles upon the back1 and keeps these in constant wing-like motion4 ,the true ,stylaria has a long trunk1 set right in the head1 and tubular 7,fig4 #f72 it grows to a considerable length1 and when in the stage of fission it is very funny to see the two proboscides waving about1 one on the middle1 as well as the original one at the head4 ,there is also a form with a shorter proboscis of the same kind4 ,bohemilla has a tremendous array of saw-like bristles upon the back1 whilst ,chtogaster has none at all in this position1 and few below4 olosoma has merely tufts of hair instead of bristles1 and swims freely4 ,it is easily recognised by the red1 yellow1 or green pigment spots in its skin1 and by the ciliated head4 ,rarest of all the family is the one which connects it with the ordinary ,tubifex1 the red worm which lives in masses in the mud of brooks and ponds1 the waving tails protruding above the water1 and being instantly withdrawn when a foot is stamped upon the bank4 ,their ,naid cousin is ,naidium1 and has red blood1 but multiplies by fission1 which ,tubifex does not4 ,another group of worms is the ,planarians1 small leech-like worms1 black1 white1 or brown1 which are rarely absent from a gathering4 ,the would-be investigator will find in them an abundant field for work1 as they are but very imperfectly known or studied4 ,the great enemy of all these worms is the ,hydra1 a good idea of which may be formed from ,plate ,,ix4 ,fig4 #ac4 ,there are three species1 all of which are fairly common4 ,they capture their prey in exactly the same way as sea-anemones and the marine hydroid forms1 so numerous and varied4 ,nor must we omit to notice the exquisitely beautiful ,polyzoa1 such as ,lophopus 7,plate ,,xiv4 ,fig4 #d71 with its ciliated tentacles and transparent social home2 ,fredericella 7,fig4 #e71 with its graceful stems1 and their still more graceful inhabitants2 and the wonderful ,cristatella1 whose colonies form bodies which crawl over the stems of water plants4 ,but for grace1 beauty1 and variety1 the ,rotifers assuredly outshine all their fellow inhabitants of our ponds and streams4 ,we can only take a few types1 and of all these the most common is the common ,rotifer 7,plate ,,ix4 ,fig4 #aj74 ,it is there shown in the act of swimming1 but it can withdraw its 8wheels0 and creep like a leech1 protruding its foot as it does so4 ,it is distinguished by the two eye-spots on the proboscis from ,philodina1 in which they are on the breast1 and ,callidina1 which has none4 ,when at ease in its mind1 the animal protrudes its wheels1 and by their action draws in particles of food1 these passing down to the incessantly moving jaws1 which act like a mill and crush the food before it passes on to be digested4 ,the movement of the jaws may even be seen in the young ,rotifer whilst still in the egg within the body of the parent1 and as the egg reaches its full development other eggs again are visible within it1 so that we may have three generations in one individual4 ,the males of most of the ,rotifera are unknown4 ,those that are known are very lowly organised1 having only the ciliary wreath and the reproductive organs1 and are only found at certain seasons of the year4 ,for the remainder of the time parthenogenesis is the rule1 just as among the ,aphides4 ,we select a few individuals for illustration as types4 ,those who wish to pursue this study further must be referred to the monumental work of ,hudson and ,gosse4 ,the common ,rotifer1 already referred to1 may be taken as the type of the ,bdelloida1 or leech-like class1 so called from their mode of 8looping0 themselves along4 ,the group is a comparatively small one in comparison with the next1 the ,ploma1 or free-swimmers4 ,we can only select from the vast variety a few species1 first of those classed as illoricated1 from their being without a lorca1 or case1 and then of the loricated1 which possess it4 ,a very large and common form is ,hydtina 7,plate ,,xiv4 ,fig4 #g71 which lives by choice in the reddish pools of water found often by the roadside4 ,it shows the whole organisation of the class magnificently2 the ciliary wreath on the head1 with the striped muscles which draw the latter back1 the powerful jaws1 the digestive canal with its crop and intestine1 the ovary with the developing eggs1 the water-vascular system with the curious vibratile tags1 and finally1 the cloaca1 which receives the waste of the body and expels it at intervals4 ,another form1 also common1 especially in clear water1 is ,synchta 7,fig4 #h71 very much like a kite or peg-top in shape1 which has the power of attaching itself by a glutinous thread1 and spinning round at a tremendous rate4 ,then there is the gigantic ,asplanchna 7,fig4 #i71 which has no opening below1 so that the waste must be discharged by the mouth2 and curious ,sacculus1 which gorges itself with chlorophyll until it looks like a green bag with a string round it1 but clear and sparkling4 ,of the ,notommat there is a whole host1 but we can only mention the beautiful ,n4 ,aurita 7,fig4 #aj71 with an eye of a beautiful violet colour1 composed of several spherules massed together1 and two curious ear-like processes on the head1 from which it takes its name4 ,some of the ,ploma have powers of leaping which must be noticed4 ,the ,triarthra 7,fig4 #aa7 has three arms1 or what we may call such1 which it can stretch out suddenly and leap to a considerable distance1 whilst in ,polyarthra the arms become a whole cluster of broad saw-like bristles4 ,we pass on to note a few species of the mail-clad or loricated ,rotifers1 chief among which the great ,euchlanis 7,fig4 #ab71 a noble-looking fellow1 calls for our attention1 his great size rendering him easily visible to the naked eye4 ,it is difficult to avoid using the masculine gender1 but1 of course1 all those figured and described are of the gentler sex4 ,salpina1 too 7,fig4 #ad71 with its box-like lorica1 armed with spines at each of the upper angles1 and having three below1 is quite easily recognised1 and very common4 ,brachionus 7,fig4 #ac7 has a shield-shaped case1 well furnished with spines1 symmetrically arranged at the top1 and an opening below for the flexible wrinkled tail1 like the trunk of an elephant4 ,pterodina 7,fig4 #ae7 has a similar tail1 but a round case1 and the head is much more like that of the common ,rotifer when extended4 ,anura 7,fig4 #af71 on the other hand1 has no tail1 and its case is shaped like a butcher's tray1 with a handle at each corner4 ,dinocharis 7,fig4 #ag7 has a roof-like case1 with long spines on the root of the tail1 and a forked stiff foot4 ,noteus 7,fig4 #ah7 is much like ,pterodina1 except in its foot1 which more nearly resembles that of ,dinocharis4 ,the list might be indefinitely extended1 but sufficient has probably been said to enable the tyro to find his bearings in this large1 beautiful1 and interesting class4 ,we pass on to notice in conclusion two or three of the fixed forms1 of which a beautiful example is the ,melicerta ringens 7,plate ,,ix4 ,fig4 #g71 whose building operations have a never-ending charm4 ,particles of dbris are accumulated in a curious little cavity in the chin1 in which they are whirled round1 and mixed with a secretion which binds them together1 and when a brick is made the head is bent down and the brick applied to the desired spot with mathematical regularity4 ,by supplying fine particles of innocuous colouring matters1 the ,melicerta may be made to build a variegated case4 ,the most remarkable specimen known is the one figured in ,hudson and ,gosse's work1 which was found by the present writer in a specimen of water from which he had already obtained five-and-twenty species of various kinds of ,rotifer2 the water was collected by an inexperienced person1 and there was only a pint of it4 ,it had1 moreover1 been kept for three weeks1 and the moral of that is1 to preserve one's gatherings1 and keep an aquarium into which they may be poured when done with for the moment4 ,new forms will often develop with startling rapidity1 their eggs having been present in the original gathering4 ,the young form of ,melicerta1 shown in ,plate ,,xiv4 ,fig4 #bj1 is strangely unlike its mother1 and much more nearly resembles its father4 ,another group of extreme beauty is the ,flosculari 7,fig4 #ai71 several species of which are very common4 ,they will be easily known by their appearance1 which resembles a shaving brush when closed2 whilst1 when opening1 the shaving brush resembles a cloud of delicate shimmering threads1 which at last stand out straight1 radiating all round the head of the creature1 and forming the trap by means of which it catches its prey4 ,finally1 there is the lovely ,stephanoceros 7not1 unfortunately1 very common71 with its five symmetrically placed and gracefully curved arms1 perhaps the most lovely of all ,rotifers1 with its exquisitely transparent body1 sparkling with masses of green and golden brown4 ,he who finds this has a treasure indeed1 and will be encouraged to prosecute his studies in this 8,fairyland of ,microscopy40 ,two irregular forms call for a word of remark4 ,the first is ,chtonotus 7,plate ,,xiii4 ,fig4 #bg71 which stands on the borderland of the ,infusoria and the ,rotifers1 neglected as a rule by the students of both2 and the second the ,tardigrada 7,plate ,,xiv4 ,fig4 #ba71 or water-bears1 which have feet like those of the red wriggling larva of ,chironomus1 whose silky tubes are common enough on submerged walls and on the stems of plants1 these feet consisting of a mass of radially arranged hooklets1 which can be protruded or withdrawn at will2 whilst the head of the water-bear is far more like that of a louse1 pointed and hard1 and suited for burrowing about1 as the animal does1 among the rubbish at the bottom of the bottle4 ,both the genera just referred to will repay careful study1 as little is known of their life-history or development4 ,a few words must be devoted1 in conclusion1 to the ,entomostraca1 those shrimp-like animals which1 like their marine relatives1 act as scavengers to the community4 ,fig4 #bb is a portrait of ,cypris1 a not very handsome form1 but one very commonly found4 ,its shell is opaque1 so that the internal organs are difficult to observe4 ,far different in this respect is the beautiful ,daphnia1 the water-flea par excellence1 whose carapace is of crystalline clearness1 so that every movement of every one of the internal organs may be followed with the greatest facility4 ,there are many species of the genus1 and some of them are very common1 so that the opportunity of examining these lovely objects is easily obtained4 ,plate ,,xiv4 ,fig4 #bc1 shows the most common of all the class under notice1 the ,cyclops1 so named from the fact that1 like the fabled giants of classical literature1 it has a single eye in the middle of its forehead4 ,it is often loaded with ,infusoria1 especially ,vorticella and ,epistylis1 already described1 to such an extent that its movements are greatly hampered4 ,,xii4 ,,fig4 #a4 ,tubercle1 ,sun-star #b4 ,zoophyte1 ,gemellaria #c4 ,cuttle bone #d4 ,plate of ditto from above #e4 ,zoophyte1 ,antennularia #f4 ,pedicellaria1 skin of ,starfish #g4 ,shell1 ,foraminifer #h4 ,snake-star1 disc from below #i4 ,pedicellaria1 ,echinus #aj4 ,wing-case1 ,weevil #aa4 ,coralline #ab4 ,spine1 ,echinus #ac4 ,foraminifer1 ,polystomella #ad4 ,do4 ,truncatulina #ae4 ,do4 ,polymorphina #af4 ,do4 ,miliolina #ag4 ,gold dust1 with quartz #ah4 ,foraminifer1 ,lagena vulgaris #ai4 ,pouches1 ,skin of ,rat's tail #bj4 ,foraminifer1 ,biloculina ringens #ba4 ,ore1 ,copper #bb4 ,zoophyte1 ,membranipora pilosa #bc4 ,human skin1 injected #bd4 ,coal1 ,longitudinal section #be4 ,do4 ,transverse section #bf4 ,lung1 ,frog ,illustration3 ,,xii4 ,we have not space to figure more of these creatures1 but other forms will be found not inferior in interest to those mentioned4 ,the most curious of all are those which earn a dishonest and lazy living by attaching themselves to the bodies of other and larger animals1 chiefly fish4 ,one of the largest is the ,argulus1 the bane of aquarium keepers1 which is of considerable size1 and attacks gold-fish1 and in fact almost any fish to which it can obtain access4 ,the gills of the stickleback will furnish examples of the curious ,ergasilus1 which consists chiefly of an enormous pair of hooks and two long egg-bags1 the latter1 in varying form1 being carried by many of the ,entomostraca4 ,upon the fins of the same fish will be found the remarkable ,gyrodactylus1 a worm-like animal which attaches itself by a large umbrella-like foot1 in the centre of which are two huge claws4 ,the head is split down the middle for some distance4 ,we may mention1 in concluding our notice of the external and involuntary guests of the unlucky stickleback1 that its skin is usually frequented by hosts of the ,trichodina described in the last chapter4 ,of the internal parasites1 want of space forbids us to speak4 ,,chapter ,x ,marine ,life--,sponges--,infusoria--,foraminife ra--,radiolaria--,hydroid ,zoophytes--,polyzoa--,worms--,lingual ,ribbons and ,gills of ,mollusca--,star-,fishes and ,sea-,urchins--,cuttle-,fish-- ,corallines--,miscellaneous ,objects4 ,great as is the range of objects presented to the student of fresh-water life1 the latter field is limited indeed as compared with that afforded by the sea4 ,the ,infusoria and ,rotifers furnished by the latter are1 indeed1 much fewer in number and variety1 but the vast host of sponges1 polyzoa1 hydroids1 crustacea1 molluscs1 ascidians1 and worms1 to say nothing of the wealth of vegetable life1 renders the sea the happy hunting-ground of the microscopist4 ,whether it be along the edge of the water1 as the tide retreats1 especially after a gale2 or in the rock-pools2 or1 perhaps best of all1 upon those portions of the shore left uncovered only by the lowest spring-tides1 the harvest is simply inexhaustible4 ,stones turned up will exhibit a world in miniature4 ,encrusted with green or pink sponges1 or with gelatinous masses of ascidians1 fringed at its edges with hydroids1 coated above with polyzoa1 a single one will often supply more work than could be got through in a week of steady application4 ,a description of the fresh-water sponge already given may serve very well to indicate the general outlines of the organisation of the marine ones too4 ,the spicules of the latter are1 however1 not always flinty2 very often1 as in the case of ,grantia 7,plate ,,ix4 ,figs4 #h and #ad71 they are calcareous1 a point which can be settled by the application of a little nitric acid and water4 ,if lime be present there will be strong effervescence1 and the separation of the spicules can only be effected by gently warming a portion of the sponge in caustic potash solution1 pouring the resulting mass into water1 and allowing the spicules to settle4 ,the washing and settling must be repeated several times1 and a portion of the deposit may then be taken up with a dipping-tube1 spread upon a slide and dried1 and then covered in balsam solution4 ,the forms are endless1 and the same sponge will often supply three or four1 or even more4 ,among them may be seen accurate likenesses of pins1 needles1 marlin-spikes1 cucumbers1 grappling-hooks1 fish-hooks1 porters'-hooks1 calthrops1 knife-rests1 fish-spears1 barbed arrows1 spiked globes1 war-clubs1 boomerangs1 life-preservers1 and many other indescribable forms4 ,the flinty forms must be prepared by boiling1 as described in speaking of the mounting of diatoms in ,chapter ,,xi41 except that1 of course1 only one settlement is required after thorough washing4 ,every one who has been by or on the sea on a fine summer night must have noticed the bright flashes of light that appear whenever its surface is disturbed2 the wake of a boat1 for example1 leaving a luminous track as far as the eye can reach4 ,this phosphorescence is caused by many animals resident in the sea1 but chiefly by the little creature represented at ,fig4 #i1 the ,noctilca1 myriads of which may be found in a pail of water dipped at random from the glowing waves4 ,a tooth of this creature more magnified is shown immediately above4 ,a large group of microscopic organisms is known to zoologists under the name of ,foraminifera1 on account of the numerous holes in their beautiful shells1 most of which are composed of carbonate of lime1 though some are horny and others are composed of aggregations of minute grains of sand1 the forms in one class often closely imitating those in another4 ,it is of the shells of these minute animals that the 8white cliffs of old ,england0 are very largely composed1 and those who desire to understand the part which these tiny creatures have played1 and are playing1 in geology1 will do well to study ,huxley's fascinating essay on 8,a ,piece of ,chalk40 ,,xiii4 ,,fig4 #a4 ,grantia compressa #b4 ,euglena viridis #c4 ,dinobryon sertularia #d4 ,synura uvella #e4 ,peridinium tabulatum #f4 ,coleps hirtus #g4 ,trachelocerca viridis #h4 ,trachelius ovum #i4 ,amphileptus gigas #aj4 ,bursaria ,mlleri #aa4 ,folliculina elegans #ab4 ,stentor polymorphus #ac4 ,trichodina pediculus #ad4 ,vorticella nebulifera #ae4 ,zoothamnium arbuscula #af4 ,do4 do4 contracted #ag4 ,vaginicola crystallina #ah4 ,ophrydium versatile 7colony7 #ai4 ,do4 do4 7single zoid7 #bj4 ,cothurnia imberbis #ba4 ,pyxicola affinis #bb-bc4 ,stylonychia mytilus #bd4 ,acineta grandis #be4 ,loxophyllum meleagris #bf4 ,euplotes charon 7dividing7 #bg4 ,chtonotus larus ,illustration3 ,,xiii4 ,the inhabitants of these shells are ,amb1 mere masses of jelly1 and some forms may be found sliding over the weeds in almost every rock-pool4 ,the anchor-mud1 already spoken of1 always contains some1 and many forms may be found in the sand from sponges1 which should be passed through a series of wire sieves1 of increasing fineness1 and the residuum in each case be examined dry under a one-inch power4 ,the shells may be picked up with a needle which has been slightly greased by being passed over the hair1 and they may be mounted by sticking them to the slide with thin starch paste1 putting on a cover-glass properly supported1 and then running turpentine under the cover-glass1 heating to expel the air1 and finally filling up with balsam4 ,or1 as opaque objects1 they may be mounted in a cell dry4 ,the forms are endless1 but all are beautiful1 and a few examples are given in ,plate ,,ix4 ,fig4 #d 7,miliolna71 and ,plate ,,xii4 ,fig4 #g1 which is a portion of the shell to show the holes1 ,fig4 #ac 7,polystomella71 ,fig4 #ad 7,truncatulna71 ,fig4 #ae 7,polymorphna71 ,fig4 #af 7,miliolna1 partly fossilised71 ,fig4 #ah 7,lagna74 and ,fig4 #bj 7,biloculna74 ,allied to these are the lovely ,radiolaria1 whose shells1 constructed on a similar plan1 are composed of flint4 ,they are found in remarkable profusion in the deposit from ,cambridge1 ,barbados1 but also in a living state at even enormous depths in the ocean4 ,the present writer has obtained many forms from ,challenger soundings1 and the great authority on this subject is ,haeckel's report in the official accounts of the expedition of the above-named vessel4 ,the ,hydroid ,zoophytes are represented by several examples4 ,these creatures are soft and almost gelatinous1 and are furnished with tentacles or lobes by which they can catch and retain their prey4 ,in order to support their tender structure they are endowed with a horny skeleton1 sometimes outside and sometimes inside them1 which is called the polypidom4 ,they are very common on our coasts1 where they may be found thrown on the shore1 or may be dredged up from the deeper portions of the sea4 ,fig4 #ac is a portion of one of the commonest genera1 ,sertularia1 showing one of the inhabitants projecting its tentacles from its domicile4 ,fig4 #ae is the same species1 given to show the egg-cells4 ,this1 as well as other zoophytes1 is generally classed among the sea-weeds in the shops that throng all watering-places4 ,the form just referred to is a near relative of the ,hydra1 already described1 and belongs to the same great family as the sea-anemones4 ,one form1 shown in ,fig4 #bf1 is the ,hydra ,tuba1 long thought to be a distinct animal1 but now known to be the young form of a jelly-fish1 or ,medusa4 ,the ,hydra ,tuba throws off joints at intervals1 each of which becomes a perfect jelly-fish4 ,one of them is shown in ,fig4 #bg4 ,fig4 #bh represents a very small and pretty ,medusa1 the ,thaumantias4 ,when this animal is touched or startled1 each of the purple globules round the edge flashes into light1 producing a most beautiful and singular appearance4 ,fig4 #bi exhibits the so-called compound eye of another species of ,medusa1 though it would appear that these are really connected with the nervous system of the animal1 and have to do with the pulsating contractions of the bell by which it is propelled through the water4 ,in my ,common ,objects of the ,sea-,shore the ,actni1 or ,sea-,anemones1 are treated of at some length4 ,at ,fig4 #af is shown part of a tentacle flinging out the poison-darts by which it secures its prey2 and ,fig4 #ag is a more magnified view of one of these darts and its case4 ,much more might be said under this head1 but we must pass on to another group1 which1 whilst possessing a certain general resemblance to the hydroid zoophytes1 differs utterly from them in internal organisation4 ,we have already referred to the fresh-water polyzoa4 ,the marine forms are vastly more numerous1 and more easily found1 since not only pieces of weed upon which they grow are to be found upon every beach1 but whole masses of leaf-like colonies1 forming what is known as horn-wrack1 may be plentifully found4 ,instead of the tentacles armed with sting-cells1 like the anemone's1 possessed by the ,hydrozoa1 the ,polyzoa have arms clothed with active cilia1 by which the food is swept into the mouth1 passing on into the stomach1 and then through the intestine to another opening4 ,fig4 #ai is a very curious zoophyte called ,anguinaria1 or snake-head1 on account of its shape1 the end of the polypidom resembling the head of the snake1 and the tentacles looking like its tongue as they are thrust forward and rapidly withdrawn4 ,fig4 #ba is the same creature on an enlarged scale1 and just below is one of its tentacles still more magnified4 ,fig4 #bc is the ladies'-slipper zoophyte 7,eretea72 and ,fig4 #bd is called the tobacco-pipe or shepherd's-purse zoophyte 7,notamia74 ,fig4 #bb is a portion of the ,bugula1 with one of the curious 8birds'-head0 processes4 ,these appendages have the most absurd likeness to a bird's head1 the beak opening and shutting with a smart snap 7so smart1 indeed1 that the ear instinctively tries to catch the sound71 and the head nodding backward and forward just as if the bird were pecking up its food4 ,on ,plate ,,xii4 ,fig4 #b1 is a pretty zoophyte called ,gemellaria1 on account of the double or twin-like form of the cells2 and ,fig4 #e represents the ,antennularia1 so called on account of its resemblance to the antenn of an insect4 ,fig4 #bb is an example of a pretty zoophyte found parasitic on many sea-weeds1 and known by the name of ,membranipora4 ,two more specimens of zoophytes may be seen on ,plate ,,xi4 as they appear under polarised light4 ,fig4 #ag is the ,cellularia reptans2 and ,fig4 #bj is the ,bowerbankia1 one form of which occurs in fresh water4 ,among the worms we may refer to the beautiful little ,spirorbis1 whose tiny coiled spiral tube may be found attached to almost every sea-weed1 and which1 when placed in a trough of sea-water1 protrudes its beautiful crown of plumes4 ,in chalk or other soft rocks1 again1 the tubes of ,spio1 with its two long waving tentacles1 may be found by hundreds4 ,then there are the centipede-like worms1 which may be found under nearly every stone1 and which belong to the great family of ,nereids1 provided with formidable jaws and stiff bristles of various forms4 ,the ,serpul are allied to the ,spirorbis already mentioned4 ,parts of the so-called feet of one of these worms are shown in ,fig4 #cf1 where the spears or 8pushing-poles0 are seen gathered into bundles1 as during life4 ,one of them1 on a larger scale1 is shown in ,fig4 #cb4 ,the gorgeous hairs of ,aphrodite have already been alluded to4 ,in the sea the few species of ,crustacea which fresh water offers to the observer in the shape of ,cyclops and its allies become thousands1 and their changes during development are numerous and puzzling4 ,who1 for example1 would suppose that the young stage of the ,cyclops was indistinguishable in habits1 and almost in form1 from that of the barnacle which adheres to the rocks8 ,yet such is the case1 and there are other metamorphoses even more startling4 ,fig4 #be is the larva of the common crab1 once thought to be a separate species1 and described as such under the name of ,zoa4 ,the ,mollusca proper will not afford us many objects1 except in the form of their lingual ribbon1 which may be extracted from the mouth1 gently heated in liquor potass1 and mounted in balsam after well washing1 when the rows of teeth form splendid objects by polarised light4 ,the palate of a whelk is shown in ,plate ,,xi4 ,fig4 #ai4 ,again1 the gills of the mussel will afford a beautiful illustration of ciliary action4 ,if a portion of the thin plates which lie along the edge of the shell be examined in a little of the liquor1 the action may be splendidly seen1 and watched for a long time 7,fig4 #ci74 ,the structure of shell1 e4g4 oyster-shell1 is well shown in three examples3 ,fig4 #cd is a group of artificial crystals of carbonate of lime2 and on ,figs4 #ch and #ci may be seen part of an oyster-shell1 showing how it is composed of similar crystals aggregated together4 ,their appearance under polarised light may be seen on ,plate ,,xi4 ,figs4 #a and #f4 ,we now pass on to the ,echinoderms1 including the star-fishes and sea-urchins4 ,the old story of the goose-bearing tree is an example of how truth may be stranger than fiction4 ,for if the fable had said that the mother goose laid eggs which grew into trees1 budded and flowered1 and then produced new geese1 it would not have been one whit a stranger tale than the truth4 ,plate ,,ix4 ,fig4 #cc1 shows the young state of one of the common star-fishes 7,comtula71 which in its early days is like a plant with a stalk1 but afterwards breaks loose and becomes the wandering sea-star which we all know so well4 ,in this process there is just the reverse of that which characterises the barnacles and sponges1 where the young are at first free and then become fixed for the remainder of their lives4 ,fig4 #cj is the young of another kind of star-fish1 the long-armed ,ophiris1 or snake-star4 ,fig4 #cg is a portion of the skin of the common sun-star 7,solaster71 showing the single large spine surrounded by a circle of smaller spines1 supposed to be organs of touch1 together with two or three of the curious appendages called pedicellari4 ,these are found on star-fishes and ,echini1 and bear a close resemblance in many respects to the bird-head appendages of the zoophytes4 ,they are fixed on foot-stalks1 some very long and others very short1 and have jaws which open and shut regularly4 ,their use is doubtful1 unless it be to act as police1 and by their continual movements to prevent the spores of alg1 or the young of various marine animals1 from effecting a lodgment on the skin4 ,a group1 of pedicellari from a star-fish is shown on a large scale on ,plate ,,xii4 ,fig4 #f1 and ,fig4 #i of the same ,plate shows the pedicellari of the ,echinus4 ,upon the exterior of the ,echini1 or sea-urchins1 are a vast number of spines having a very beautiful structure1 as may be seen by ,fig4 #ce1 ,plate ,,ix41 which is part of a transverse section of one of these spines4 ,an entire spine is shown on ,plate ,,xii4 ,fig4 #ab1 and shows the ball-and-socket joint on which it moves1 and the membranous muscle that moves it4 ,fig4 #h is the disc of the snake-star as seen from below4 ,fig4 #a is a portion of skin of the sun-star1 to show one of the curious madrepore-like tubercles which are found upon this common star-fish4 ,fig4 #c is a portion of cuttle 8bone10 very slightly magnified1 in order to show the beautiful pillar-like form of its structure2 and ,fig4 #d is the same object seen from above4 ,when ground very thin this is a magnificent object for the polariscope4 ,one or two miscellaneous objects now come before our notice4 ,fig4 #aa is one of those curious marine plants1 the ,corallines1 which are remarkable for depositing a large amount of chalky matter among their tissues1 so as to leave a complete cast in white chalk when the coloured living portion of the plant dies4 ,the species of this example is ,jania rubens4 ,fig4 #ai is part of the pouch-like inflation of the skin1 and the hairs found upon the rat's tail1 which is a curious object as bearing so close a similitude to ,fig4 #bb1 the sea-mat zoophyte4 ,fig4 #bc is a portion of the skin taken from the finger1 which has been injected with a coloured preparation in order to show the manner in which the minute blood-vessels or 8capillaries0 are distributed2 and ,fig4 #bf is a portion of a frog's lung1 also injected4 ,the process of injection is a rather difficult one1 and requires considerable anatomical knowledge4 ,the principle is simple enough1 being merely to fill the blood-vessels with a coloured substance1 so as to exhibit their form as they appear while distended with blood during the life of the animal4 ,it sometimes happens that when an animal is killed suddenly without effusion of blood1 as is often seen in the case of a mouse caught in a spring trap1 the minute vessels of the lungs and other organs become so filled with coagulated blood as to form what is called a natural injection1 ready for the microscope4 ,before leaving the subject ,i must ask the reader to refer again for a moment to the frog's foot on ,plate ,x41 and to notice the arrangement of the dark pigment spots4 ,it is well known that when frogs live in a clear sandy pond1 well exposed to the rays of the sun1 their skins are bright yellow1 and that when their residence is in a shady locality1 especially if sheltered by heavy overhanging banks1 they are of a deep blackish-brown colour4 ,moreover1 under the influence of fear they will often change colour instantaneously4 ,the cause of this curious fact is explained by the microscope4 ,under the effects of sunlight the pigment granules are gathered together into small rounded spots1 as seen on the left hand of the figure1 leaving the skin of its own bright yellow hue4 ,in the shade the pigment granules spread themselves so as to cover almost the entire skin and to produce the dark brown colour4 ,in the intermediate state they assume the bold stellate form in which they are shown on the right hand of the round spots4 ,very remarkable forms of these cells may be found in the skin of the cuttle-fish4 ,figs4 #bd and #be are two examples of coal1 the former being a longitudinal and the latter a transverse section1 given in order to show its woody character4 ,fig4 #ag is a specimen of gold-dust intermixed with crystals of quartz sand1 brought from ,australia2 and ,fig4 #ba is a small piece of copper-ore4 ,every possessor of a microscope should1 as soon as he can afford it1 add to his instrument the beautiful apparatus for polarising light4 ,the optical explanation of this phenomenon is far too abstruse for these pages1 but the practical application of the apparatus is very simple4 ,it consists of two prisms1 one of which1 called the polariser1 is fastened by a catch just below the stage2 and the other1 called an analyser1 is placed above the eye-piece4 ,in order to aid those bodies whose polarising powers are but weak1 a thin plate of selenite is generally placed on the stage immediately below the object4 ,the colours exhibited by this instrument are gorgeous in the extreme1 as may be seen by ,plate ,,xi41 which affords a most feeble representation of the glowing tints exhibited by the objects there depicted4 ,the value of the polariser is very great1 as it often enables observers to distinguish1 by means of their different polarising properties1 one class of objects from another4 ,if the expense of a polarising apparatus be too great for the means of the microscopist1 he may manufacture a substitute for it by taking several thin plates of glass1 arranging them in a paper tube so that the light may meet the surface of the lowest one at an angle of about #eb1 and placing the bundle above the eye-piece to act as an analyser2 whilst1 by using a plate of glass1 and so arranging the lamp that the light falls upon it at the above angle1 and is reflected up the tube of the microscope1 he will find on rotating the extemporised analyser that the phenomena of polarisation are to a great extent reproduced2 whilst by splitting an extremely thin film from the surface of a sheet of mica1 such as is employed for making smoke-screens above glass globes1 he will have a substitute for the selenite by means of which alone can the gorgeous effects be produced4 ,the extemporised apparatus will not1 of course1 give such perfect effects1 but this is sometimes an advantage1 and the present writer has used the same means with considerable success in photographing starch-granules4 ,,xiv4 ,,fig4 #a4 ,dero latissima #b4 ,slavina serpentina #c4 ,pristina longiseta #d4 ,lophopus crystallinus #e4 ,fredericella sultana #f4 ,stylaria proboscidea 7head7 #g4 ,hydatina senta #h4 ,synchta mordax #i4 ,asplanchna ,brightwellii #aj4 ,notommata aurita #aa4 ,triarthra longiseta #ab4 ,euchlanis triquetra #ac4 ,brachionus amphiceros #ad4 ,salpina mucronata #ae4 ,pterodina patina #af4 ,anura brevispina #ag4 ,dinocharis tetractis #ah4 ,noteus quadricornis #ai4 ,floscularia ornata #bj4 ,young ,melicerta #ba4 ,macrobiotus 7sp487 #bb4 ,cypris fusca #bc4 ,cyclops quadricornis ,illustration3 ,,xiv4 ,,chapter ,,xi ,hints on the ,preparation of ,objects--,preservative ,fluids--,mounting ,media--,treatment of ,special ,objects4 ,the microscopist who relies altogether on the dealer for his permanent preparations may expend a good deal of money1 but the satisfaction which he derives from his hobby will be very inferior to that experienced by the worker who endeavours to secure1 for exhibition or for reference1 specimens of the objects which he finds most interesting and instructive to himself4 ,it will be our endeavour in the following pages to give a summary of the elementary principles upon which reliance is to be placed1 though it must be clearly understood that the technique of the subject1 already occupying a vast amount of literature1 is extending day by day1 so that it is impossible to deal exhaustively even with one single section of it4 ,reference must be made1 for further information1 to such publications as the ,journal of the ,royal ,microscopical ,society1 or that of the ,quekett ,club1 or to the monographs on the various departments4 ,davies' work on the general subject will also be found useful by the beginner4 ,taking first the question of reagents1 we may mention five which leave the cells of a tissue as nearly as possible in the natural condition1 but fit for permanent preservation4 ,the first of these1 in order of importance and of general applicability1 is alcohol1 represented for most purposes by methylated spirit1 which contains about #hd per cent4 of absolute alcohol1 though1 unfortunately for our purpose1 there is a certain quantity of mineral naphtha in it in addition4 ,this last has the effect of making it go milky upon dilution with water1 which is a considerable disadvantage1 though the milkiness disappears to some extent on standing1 and it is rarely worth the while of the ordinary microscopist to go through the formalities necessary to obtain permission to purchase unmineralised spirit1 which cannot be had in quantities of less than five gallons 7as it is only to be had from the distillers under an ,excise permit71 and distillers may not supply less4 ,four parts of methylated spirit with one of water forms the classical 8#gj per cent40 alcohol1 the most generally useful of all fluids for hardening and preserving purposes4 ,a considerable quantity of this fluid should always be available4 ,whatever other fluid may be used to begin with1 spirit must almost always be used to finish the process1 and fit the tissue for section-cutting and staining4 ,of purely preservative1 or fixative1 fluids1 we may mention 8formalin10 a #dj per cent4 solution of formic aldehyde1 which is rapidly coming to the front1 as indeed it deserves to do4 ,it is but slightly poisonous1 if at all1 and leaves in the tissue nothing which requires subsequent removal before proceeding to harden for section-work1 whilst it is an admirable preservative of cell-form4 ,another admirable but highly poisonous reagent is corrosive sublimate1 in saturated solution1 with #b per cent4 of acetic acid4 ,a fourth is osmic acid1 used in #a per cent4 solution4 ,this is a highly valuable reagent1 but extremely expensive1 very poisonous1 and giving off fumes which are most irritating to the eyes4 ,the fifth1 a very gentle1 but in many respects very satisfactory one1 is picric acid in saturated solution4 ,tissues preserved in this medium must not be washed out with water1 as it enters into very feeble combination with protoplasm1 and the cells swell and disintegrate as the reagent is dissolved out4 ,of mounting media we may mention glycerine1 glycerine jelly 7made by dissolving starch in glycerine with the aid of heat71 and ,canada balsam1 dissolved in xylol or benzole4 ,the ,canada balsam must be dried hard by evaporation over a water-bath1 and dissolved as wanted4 ,under no circumstances should raw balsam be used1 as it takes years to set hard1 and turns of a deep yellow colour in the process4 ,chloroform is frequently used as a solvent1 but it has the disadvantage of attacking and extracting a large number of the aniline dyes used for staining structures1 an objection from which the mineral solvents are free4 ,we will now proceed to go through the objects already referred to1 and indicate the method of preservation4 ,for the study of the cell-structures of plants the portion to be examined is to be placed in spirit of about #cj per cent4 strength1 which is changed after twenty-four hours for #dj per cent41 after a further twenty-four hours for #ee per cent41 and finally1 as regards our present purpose1 in #gj per cent4 spirit1 in which it may remain until required for section-cutting4 ,the effect of this treatment is to extract the bulk of the water from the tissue1 with the minimum of shrinkage of the cells1 the latter being preserved in their natural relations to surrounding parts4 ,in some cases1 however1 it is desirable to examine and preserve delicate structures1 or parts1 or dissections1 in a medium which allows of the retention of the greater part of the natural moisture1 and in such a case the tissue is immersed in glycerine diluted very much in the same way as the alcohol in the last process1 but with very much longer intervals between the alterations of strength1 until it reaches pure glycerine1 in which it remains for a considerable time1 as the exchange between the tissue and the dense fluid surrounding it goes on very slowly4 ,a combination of the two methods is also possible1 the spirit-hardening being carried out for a portion of the time1 and the tissue being thereafter transferred to glycerine1 diluted or pure4 ,the object of using glycerine at all is merely that it has a much lower refractive index than balsam1 so that delicate structures may sometimes be better seen in the former medium1 but balsam is to be preferred wherever it is possible to use it1 i4e4 almost always4 ,the writer has not mounted a preparation in glycerine or a medium containing it for many years1 nor1 with proper staining1 does he think it can ever be necessary to do so1 except in the case of dissections in which the glycerine can be slowly run in without disturbing the arrangement1 as spirit would be pretty sure to do4 ,the harder portions of plants1 woody stems1 shells of fruit1 or the like1 require different treatment1 and must1 as a rule1 be allowed to dry thoroughly before being cut4 ,starch granules are somewhat troublesome to mount satisfactorily4 ,the writer has tried many methods1 and1 on the whole1 prefers a glycerin-gelatin medium1 which keeps for an almost indefinite time1 and may be made as follows3 ,thirty grains of gelatine 7,nelson's 8brilliant0 or other transparent gelatine is to be preferred7 are allowed to soak in water1 and the swollen gelatine is drained1 and dissolved in the water which it has absorbed1 by the aid of a gentle heat4 ,an equal bulk of pure glycerine is then added4 ,in using1 a small portion is transferred to a slide with the point of a knife and melted1 a small quantity of starch granules added1 and stirred into it with a needle4 ,the cover-glass is then laid up on the still-fluid drop1 pressed gently down so that the drop is extended to the margin of the cover1 and the whole allowed to cool4 ,it is then to be painted round with several layers of ,brunswick black1 or ,hollis's glue1 or zinc-white cement1 to prevent evaporation1--,hollis's glue being perhaps the best medium for the purpose4 ,petals1 or other parts of which it is desired to obtain a surface view1 must be mounted in cells1 which may be made by the use of button-moulds of suitable size1 cemented to the glass slide with marine glue4 ,the slide must be free from grease1 as the tissue must be fixed in position by the use of gum1 and allowed to dry thoroughly before closing the cell1 or the cover-glass will be bedewed with moisture when the cell is closed4 ,the best plan is1 after air-drying for a couple of days1 to place the preparation on a metal plate over a beaker of boiling water for an hour or more1 and then to close the cell immediately with ,brunswick black1 maintaining the heat at first to ensure rapid drying1 and then slowly withdrawing it4 ,when cool1 another coat should be given1 and rather thick covers should be used1 as these preparations are never required to be examined with high powers4 ,to mount pollen-grains1 they should be sprinkled upon the surface of a slide which has been previously moistened with thin gum1 and allowed to dry until it has become just 8tacky02 the drying is then completed by gentle heat and a drop of balsam placed upon the grains1 with a cover-glass over all4 ,bubbles will probably form1 but with ,canada balsam this is not of the slightest importance1 as they always come out of their own accord1 and balsam mounts should never be closed with cement of any kind until thoroughly dry4 ,air-bubbles in other media may be eliminated by the use of the air-pump shown in ,fig4 #af1 which may be obtained from ,baker at a very reasonable rate1 and which is useful not only for that purpose1 but for accelerating the drying of moist tissues4 ,to do this1 there is placed upon the plate of the pump a porcelain dish containing strong sulphuric acid1 and upon this is placed a little triangle of platinum wire1 which serves to support the preparation4 ,the air is now exhausted2 the tissue parts with moisture to supply its place1 and this moisture is in turn greedily absorbed by the sulphuric acid1 so that drying is rapid and continuous1 as well as very thorough1 whilst the process has the great advantage of dispensing entirely with the use of heat4 ,illustration3 ,fig4 #af4 ,portions of many of the delicate alg may be mounted in glycerine1 having previously been soaked in it as already described2 whilst the unicellular forms1 such as desmids and diatoms1 may be preserved in almost exactly the natural condition by simply mounting them in a saturated solution of picric acid4 ,probably formalin1 in a solution of #aj per cent4 strength1 would answer the purpose equally well1 but the writer has not tried it4 ,it is hardly necessary to say that1 with such extremely fluid media1 great care is required in closing the cell4 ,a thin layer of ,hollis's glue should be first painted on1 to secure the cover in position1 and when this is thoroughly dry1 several successive layers must be added in the same way4 ,it may be said here1 that it is advisable in all cases to use circular cover-glasses1 as far as possible1 as they lend themselves with great facility to a mechanically accurate closure4 ,this slide is placed upon a turn-table1 carefully adjusted until the cover is seen to be central when rotated1 and a brush1 preferably a small camel-hair pencil1 charged with the desired fluid1 but not in large excess1 is held against the junction of the slide and cover1 whilst the table is rapidly spun4 ,a little experience will teach better than any description what amount of fluid there should be in the brush1 and how thick the cement should be4 ,if too thick1 it will drag off the cover2 if too thin1 it will flow over the latter and over the slide4 ,the preparation of diatom-skeletons as permanent objects is easy4 ,consisting1 as they do1 of pure silex1 or flint1--i4e41 practically glass1--they resist long boiling in acids1 so that there is little difficulty in isolating them from any organic matter with which they are mingled4 ,it is generally recommended to treat them with strong nitric acid4 ,this is a mistake4 ,the acid acts much more powerfully and less violently when diluted with an equal bulk of water1 and it is in an acid so diluted that portions of water-plants1 or other diatomaceous material1 should be boiled in a glass beaker until all the organic matter is dissolved4 ,the beaker should be covered with a glass plate1 to prevent dissipation of the acid fumes4 ,when the process is complete1 usually in about half an hour1 the contents of the beaker are thoroughly stirred with a glass rod1 poured rapidly off into a larger bulk of cold water1 and allowed to settle for another half-hour4 ,the process is then repeated with a smaller bulk of water1 several times1 to allow the removal of the last traces of acid1 and finally with distilled water4 ,the separation of the diatoms into grades is effected by settlement4 ,the final result is poured into a tall glass vessel1 and allowed to settle for1 at first1 a minute1 the supernatant fluid again poured off1 and allowed to settle for two minutes1 and so on1 the period being gradually increased1 and each sediment preserved apart4 ,the first will probably only be sand1 but the proportion of diatoms will increase with each separation1 though there will always be a certain proportion of sand of such a size as to settle at the same rate as the diatoms4 ,marine plants especially will furnish a rich harvest by treatment as described4 ,solid diatomaceous deposits1 such as kiesel-guhr1 mountain-meal1 and especially the famous ,oamaru deposit from ,new ,zealand1 demand different treatment1 and perhaps the best way is to disintegrate the mass1 either by boiling with ,sunlight soap 7though the alkali attacks the flint to some extent7 or to mix the mass with a super-saturated solution of acetate of soda 7made by saturating water with the crystals whilst boiling71 and by successive coolings1 heatings1 and stirrings to cause the process of crystallisation to break up the mass1 which it will do very thoroughly4 ,the diatoms are then separated by sedimentation1 as above described4 ,a small portion of the deposit may now be spread thinly on a glass slide1 allowed to dry thoroughly1 be treated with balsam1 and covered4 ,if it be desired to select individual diatoms1 this must be done under the microscope1 by means of a bristle fixed in a handle either with glue or sealing-wax4 ,the diatom selected will adhere to the bristle if the latter be slightly greasy1 and should then be transferred to a slightly adhesive slide1 coated either with thin solution of white shellac1 or with thin gum nearly dry4 ,when the forms desired are mounted1 the preparation should be covered in balsam4 ,the process is by no means as easily effected as described1 however4 ,the preparation of insects1 or parts of insects1 as microscopic objects is a tedious and difficult task4 ,the main point is the trouble of softening the integument and eliminating the colour4 ,the latter can1 in any case1 be only partially effected4 ,the beginner would do well to begin with a fairly easy form1 such as the worker-ant4 ,a good supply of these insects may be placed in a bottle of liquor potass1 and left there for at least some days until they begin to become clear and limp4 ,from time to time a specimen may be taken1 well washed with several waters1 then with acetic acid and water of a strength of about #aj per cent41 then with weak spirit1 about #ej per cent4 ,an attempt may then be made to arrange the insect upon a slide1 spreading out the legs so as to exhibit them to the best advantage1 and when this has been done a cover-glass may be put on1 supported in such a way as to prevent absolute pressure4 ,the spirit is then withdrawn by means of a piece of filtering-paper cut to a point1 and strong spirit added4 ,this is again succeeded by absolute alcohol1 then by a mixture of turpentine and crystal carbolic acid in equal proportions1 and finally the cover-glass is carefully lifted1 and some thick balsam solution dropped on1 the limbs finally arranged by means of warm needles1 and the cover-glass carefully replaced and pressed gently down by means of a clip1 which may be obtained for a few pence4 ,the whole is then set aside to harden1 the deficiency caused by evaporation made good1 the balsam allowed to dry1 and the preparation finally painted round4 ,the contents of the body1 in large insects1 must be removed1 and this is effected during the washing in water by gentle pressure with a camel-hair brush1 the process being aided1 if necessary1 by a small incision made through the integument at the root of the tail4 ,sections of insects require very special methods1 which will hardly fall within the scope of this work4 ,,chapter ,,xii ,section-,cutting--,staining ,no method of examination can equal1 for general applicability and usefulness1 that of section-work4 ,the relations of the parts to each other being preserved1 it is possible to draw conclusions as to their actual relations which no other mode allows of1 and we shall devote this concluding chapter to some account of the methods to be employed to this end4 ,the apparatus required is not necessarily complicated4 ,reduced to its elements1 it consists essentially only of a razor to cut the sections and a dish to receive them4 ,it but seldom happens1 however1 that the relations of the parts in sufficiently thin sections can be preserved by such a rough-and-ready method1 and frequently the object to be cut is of such small dimensions as to render it impossible to deal with it in this way4 ,it is therefore necessary to 8imbed0 it1 so as to obtain a handle by which to hold it1 in such a way that it shall be equally supported in all directions4 ,moreover1 since the human hand can only in exceptional cases be brought to such a pitch of skill as to cut a series of sections1 or even single ones1 of the needful delicacy1 some mechanical means of raising the object through a definite distance is highly desirable4 ,the writer has cut many thousands of sections with the 8free hand10 but the personal equation is a large one1 and is not always the same in the same person4 ,for single sections the method will1 with practice1 succeed very well1 but some means of securing a number of sections of more or less the same thickness is usually required4 ,let us deal with the imbedding first4 ,if it be desired to imbed a tissue which has merely been fixed with formalin1 the block should be immersed in strong gum 7made by saturating water with picked gum arabic1 white and clean7 for several days4 ,it is then taken out and1 without draining1 transferred to the plate of a freezing microtome1 and the sections cut from the frozen block1 and mounted in glycerine at once4 ,this plan is of limited usefulness1 since it allows of very little differentiation of the tissue elements1 and that only optical4 ,to get the best results1 some plan of staining must be adopted4 ,perhaps the simplest1 and certainly a very excellent one1 is as follows4 ,after the tissue has been passed from the hardening1 or fixing1 fluid into the successive alcohols1 as described1 it is placed in the following solution4 ,take about forty grains of carmine and eighty grains of borax1 dissolve in about an ounce of water1 add to the mixture an ounce of methylated spirit1 and let it stand for some time with frequent shaking2 about a week will be sufficient1 and the process of solution may be hastened by gentle warming at intervals4 ,the clear upper portion is then poured off1 and into this the block of tissue is dropped1 and allowed to remain until thoroughly penetrated4 ,perhaps the best plan is to substitute the carmine solution for the #ej per cent4 alcohol1 and thus to make the staining a stage in the hardening process4 ,from the carmine solution the tissue is transferred to #gj per cent4 alcohol1 to each ounce of which two drops of hydrochloric acid have been added1 and after remaining in it for a day 7with a piece of the usual size7 is placed in #gj per cent4 alcohol1 in two successive quantities4 ,sections from this material now only require treatment with the carbolic acid and turpentine above mentioned to be fit for mounting and covering in balsam4 ,we now proceed to indicate how the sections may be cut4 ,a mixture of wax and almond oil1 in proportions varying with the heat of the weather1 usually about equal ones1 is prepared4 ,the piece of tissue is freed from superfluous spirit by being placed on a bit of blotting-paper for a minute or two1 and is then immersed in a quantity of the wax-and-oil mixture contained in a little box of paper or lead-foil4 ,the tissue is held on the point of a needle1 and lifted up and down until it is coated with the mixture1 and1 before solidification of the mass sets in1 is lowered into the box and left to cool4 ,the block now furnishes a handle1 and this should be wrapped round with paper1 the sections cut with the keenest possible razor1 and as thin as possible1 and placed in spirit as cut4 ,from the spirit1 which must be the strongest obtainable1 they are placed in the clearing liquid1 carbolic and turpentine1 and then slid on to the slide1 a drop of balsam placed on the section1 and the cover over all4 ,of late years all sections of ordinary soft tissues1 animal or vegetable1 have been cut by one of the infiltration methods1 in which the interstices of the tissue are filled up by some material which prevents the relations of the cells from being altered during the process of cutting4 ,to enter fully into this matter would occupy too much space1 and would serve no useful purpose1 for the worker who requires to make use of such means will find it indispensable to obtain ,bolles ,lee's ,microtomist's ,vade ,mecum1 in which the whole matter is exhaustively treated4 ,the simple method above detailed will answer most ordinary purposes1 provided that a few precautions be attended to4 ,the chief are as follows4 ,the outside of the block of tissue must be sufficiently dry for the wax-and-oil to adhere to it4 ,the razor must be extremely sharp1 and must be kept so by application to a ,turkey stone during the section-cutting4 ,the blade must be drawn across the tissue from heel to point1 and kept wetted with spirit the whole time1 so as to prevent any dragging of the section4 ,the transference of the section to the slide must be effected by means of a section-lifter1 which may be made by beating out a piece of stout copper wire to a thin flat blade2 or a small palette-knife1 or ,german-silver lifter1 may be purchased for a few pence4 ,the carbolic turpentine is best used by placing a little in a watch-glass1 and floating the sections on to it by lifting them singly with the lifter1 freeing them from superfluous spirit by draining on to blotting-paper1 and allowing them to float on to the surface of the liquid in the watch-glass1 so that the spirit may evaporate from above1 and be replaced by the clearing agent from below ,the balsam solution should be thin1 and the cover-glass must be allowed to settle down into place without pressure4 ,the question of staining sections is a very large one1 and is becoming of daily increasing complexity4 ,we cannot go into it here1 further than to say that most sections cut from unstained tissue will yield excellent results if stained first with ,delafield's logwood solution 7to be obtained at ,baker's7 to a very slight extent1 and then with a solution of safranin4 ,the sections should be washed with tap-water after the logwood stain1 and should be of a pale violet colour4 ,if over-stained1 the colour may to a great extent be removed by washing with a very weak solution of hydrochloric acid1 about two drops of acid to each ounce of water1 and repeated washing in tap-water to remove the acid1 and restore the violet4 ,the safranin stain should be weak1 and should be allowed to act for some time4 ,from this last the sections are transferred to strong spirit1 the latter being renewed until the sections cease to give up the red dye2 and they may then be mounted as described4 ,the results with most tissues are superb1 every detail of the structure being splendidly brought out4 ,safranin alone is also an admirable stain for many purposes4 ,further information must be sought in the book already mentioned4 ,let us1 in closing1 warn the beginner of two things which are of general application in practical microscopy4 ,the first is1 not to be discouraged by failures4 ,the manipulations are in many cases very delicate1 and premiums must be paid to experience for insurance against failure in every one of the processes4 ,the second is1 that the most scrupulous cleanliness will hardly suffice to prevent contamination of preparation by the all-pervasive dust which1 invisible to the eye1 assumes colossal proportions under the microscope1 and the particles of which have an unpleasant habit of collecting on the most interesting or most beautiful portion of the preparation4 ,this can only be guarded against by careful filtration of all fluids1 and constant watchfulness4 ,a preparation properly made is a thing of beauty1 and a joy for ever1--or if not for ever1 at any rate for many years2 and one such will repay an infinitude of pains taken in its production4 ,,index ,,page ,air-pump1 #agd ,alg1 #gh marine1 #ib ,anemones1 sea1 #aei ,antenn1 #if ,ants1 #ig ,bacillaria1 #hg ,balancers of ,fly1 #aab ,bark1 #fa ,blights1 #hi ,blood1 circulation of1 #abi corpuscles of1 #abh ,bone1 #abc ,breathing-tubes1 #aji ,bull's-eye1 use of1 #cb ,camera lucida1 #be ,canada ,balsam1 #agj ,cartilage1 #abd ,cells1 animal1 #abb circulation in1 #dj mounting dry in1 #agc pigment1 #aba1 #afe spiral1 #df vegetable1 #cg ,ceramidia1 #ic ,chlorophyll1 #dj ,compressorium1 ,beck's1 #ah ,condenser1 bull's-eye1 #ai substage1 #ai ,conferv1 #hd ,conjugation1 #hb1 #hd ,convex lenses1 #g foci of1 #g1 #h image formed by1 #aj virtual image1 #aa ,corallines1 #afd ,corrosive sublimate1 #agj ,cover-glasses1 #ah ,desmids1 #ha ,diatoms1 #he preparation of1 #age ,dipping-tubes1 #bb ,dissection1 #bj instruments1 #ba under microscope1 #bd ,drawing1 #be squares1 #bf ,echinoderms1 #afb ,entomostraca1 #aeb ,epidermis1 animal1 #abb vegetable1 #fh ,extemporised apparatus1 #e ,feathers1 #aai ,fish1 scales of1 #aah parasites of1 #aec ,fixation of cell-forms1 #aga ,focus of mirror1 #bi ,foraminifera1 #aef ,formalin1 #afd ,frog-plate1 #abi ,gills of mussel1 #abb ,gizzard of insects1 #aji ,glycerine-gelatine1 #agb jelly1 #aga ,hairs1 animal1 #aaf vegetable1 #ec ,heads of ,insects1 #ajd ,illumination1 correct1 #ca1 #cb dark-field1 #cd for opaque objects1 #cc ,imbedding1 #ahj by infiltration1 #ahb ,infusoria1 #ace ,injection1 #afd ,insects1 #ig mounting of1 #agg ,jelly-fish1 #aeh ,larva of ,chironomus1 #aeb ,light1 arrangement of1 #bi ,live-box1 #ag ,logwood solution1 #ahc ,magnification1 to measure1 #bg ,mare's tail1 #ia ,marine life1 #aee ,microscope1 ,baker's1 #ad 8portable01 #ae primitive1 #e simple1 #ab1 #ac ,mildew1 #hi ,mirror1 concave1 #bi ,mollusca1 #afa ,mounting1 #afh dry1 #agc foraminifera1 #aeg ,mosses1 #if ,muscle1 #abg ,nails1 #abd ,needles1 #bb ,nerve1 #abg ,net1 #acc ,nucleus1 #dj ,objectives1 #af ,objects1 drawing of1 #bd photography of1 #cf ,oil-cells1 #eh1 #fa ,oscillatori1 #hd ,osmic acid1 #agj ,parasites1 #aec ,petals1 #fi ,picric acid1 #agj ,pigment1 #aba ,pocket magnifiers1 #ac ,polariscope1 #aff ,pollen1 #ga ,polyzoa1 #adg ,pond-hunting1 #acb ,preservatives1 #afi ,radiolaria1 #aeg ,rotifers1 #adg ,safranin stain1 #ahc ,sap1 #abh ,scent-glands1 #eg ,sea-weeds1 #ib ,section-cutting1 #agh ,seeds1 #ge ,skin1 #abj ,spiracles1 #ajb ,sponge1 fresh-water1 #ace spicules1 #aee ,sporangia1 #ib ,stage-forceps1 #aaf ,starch1 #fc mounting1 #agb ,stomata1 #di ,suckers1 #ajh ,teeth1 #abe ,troughs1 glass1 #ah ,water-bears1 #aeb ,wings1 #aaj ,wool1 #aaf ,worms1 fresh-water1 #ad marine1 #afj ,yeast1 #hi ,zoa1 #afa ,zoophytes1 #aeg ,zygnemace1 #he ,,printed ,,by ,,morrison ,,and ,,gibb ,,limited1 ,,edinburgh