UC-NRLF 
 
 
 
I 
 
11 
 
DECEIVED, ...".. J 7 
 
 COMMON OBJECTS 
 
 OF 
 
 THE MICROSCOPE. 
 
 BY THE 
 
 KEY. J. G. WOOD, M.A. F.L.S. ETC. 
 
 AUTHOR OF "COMMON OBJECTS OF THE COUNTRY AM> SEA-SHORE/ 
 " ILLUSTRATED NATURAL HISTORY," ECT. F.CT. 
 
 WITH ILLUSTRATIONS BY TUFFEN WEST. 
 PRINTED IN COLOURS BY EVANS. 
 
 LONDON : 
 
 GEOEGE EOUTLEDGE AND SONS ; 
 THE BROADWAY, LUDGATE. 
 
WOOD'S 
 COMMON OBJECTS OF THE MICEOSCOPE, 
 
 A Cheap Edition of this Work, with the Illustrations, ia 
 to be obtained, price One Shilling. 
 
 BIOLOGY 
 GIFT 
 
PEEFACE. 
 
 IN my two previous handbooks, the "Common, 
 Objects " of the Sea-shore and Country, I could but 
 slightly glance at the minute beings which swarm in 
 every locality, or at the wonderful structures which 
 are discovered by the Microscope within or upon the 
 creatures therein described. Since that time a general 
 demand has arisen for an elementary handbook upon 
 the Microscope and its practical appliance to the study 
 of nature ; and in order to supply that want, this little 
 volume has been produced. 
 
 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 fields, but 
 merely one by which he will be enabled to guide 
 himself in microscopical research, and avoid the loss 
 of time and patience which is almost invariably the 
 lot of the novice in these interesting studies. Upwards 
 of four hundred objects have been figured, including 
 many representatives of the animal, vegetable, and 
 
 426 
 
IV PREFACE. 
 
 mineral kingdoms, and among them the reader will 
 find types sufficient for his early guidance. 
 
 Neither must he expect that any drawings can 
 fully render the lovely structures which are revealed 
 by the microscope. Their form can be given faith- 
 fully enough, and their colour can be indicated; but 
 no pen, pencil, or brush, however skilfully wielded, 
 can reproduce the soft, glowing radiance, the delicate 
 pearly translucency, or the flashing effulgence of living 
 and ever-changing light with which God wills to imbue 
 even the smallest of his creatures, whose very existence 
 has been hidden for countless ages from the inquisitive 
 research of man, and whose wondrous beauty astonishes 
 and delights the eye, and fills the heart with awe and 
 adoration. 
 
 Owing to the many claims on my time, I left the 
 selection of the objects to Mr. Tuffen "West, who 
 employed the greater part of a year in collecting 
 specimens for the express purpose, and whose well- 
 known fidelity and wide experience are the best 
 guarantees that can be offered to the public. To him 
 I also owe many thanks for his kind revision of the 
 proof-sheets. My thanks are also due to Messrs. 
 G. and H. Brady, who lent many beautiful objects, 
 and to Messrs. Baker, the well-known opticians of 
 Holborn, who liberally placed their whole stock of 
 slides and instruments at my disposal. 
 
THE MICROSCOPE. 
 
 CHAPTER I. 
 
 INTRODUCTION USES OF THE MICROSCOPE VALUE OF CAREFUL 
 OBSERVATION EARLY DISCOVERIES EXTEMPORIZED INSTRU- 
 MENTS. 
 
 IN the following pages I propose to carry out, as far 
 as possible, with regard to the MICROSCOPE, the system 
 which I have previously followed in the "Common 
 Objects of the Sea-Shore and Country," and to treat 
 in a simple manner of those wonderful structures, 
 whether animal, vegetable, or mineral, which are found 
 so profusely in our fields, woods, streams, shores, and 
 gardens. Moreover, I intend to restrict my observations 
 wholly to that class of instrument which can be readily 
 obtained and easily handled, and to those supple- 
 mentary pieces of microscopic apparatus which can 
 be supplied by the makers at a cost of a few shillings, 
 
 B 
 
2 USES OP THE MICROSCOPE. 
 
 or extemporized by the expenditure of a few pence 
 and a little ingenuity on the part of the observer. As 
 in the former works, ordinary and familiar English 
 terms will in every case be used where their employ- 
 ment is possible; but as, on account of their extremely 
 minute dimensions, no popular name has been given to 
 very many objects, we must be content to accept the 
 more difficult language of science and render it as 
 little abstruse as possible. 
 
 Within the last few years, the microscope has become 
 so firmly rooted among us, that little need be said in 
 its praise. The time has long passed away when it 
 was held in no higher estimation than an ingenious 
 toy ; but it is now acknowledged, that no one can attain 
 even a moderate knowledge of any physical science with- 
 out a considerable acquaintance with the microscope 
 and the marvellous phenomena which it reveals. The 
 geologist, the chemist, the mineralogist, the anatomist, 
 or the botanist, all find the microscope a useful com- 
 panion and indispensable aid in their interesting and 
 all-absorbing researches, and, with every improvement 
 in its construction, have discovered a corresponding 
 enlargement and enlightenment of the field displayed 
 by the particular science which they cultivate. 
 
 But even to those who aspire to no scientific emi- 
 nence, the microscope is more than an amusing com- 
 
USES OF THE MICROSCOPE. 3 
 
 panion, revealing many of the hidden secrets of Nature, 
 and unveiling endless beauties which were heretofore 
 enveloped in the impenetrable obscurity of their own 
 minuteness. 
 
 No one who possesses even a pocket-microscope of 
 the most limited powers can fail to find amusement 
 and instruction, even though he were in the midst of 
 the Sahara itself. There is this great advantage in the 
 microscope, that no one need feel in want of objects as 
 long as he possesses his instrument and a sufficiency 
 of light. 
 
 Many persons who are gifted with a thorough ap- 
 preciation of nature in all her vivid forms are debarred 
 by the peculiarity of their position from following out 
 the impulses of their beings, and are equally unable to 
 range the sea-shore in search of marine creatures or to 
 traverse the fields and woods in the course of their in- 
 vestigations into the manifold forms of life and beauty 
 which teem in every nook and corner of the country. 
 Some are confined to their chambers by bodily ailments, 
 some are forced to reside within the very heart of some 
 great city, without opportunities of breathing the fresh 
 country air more than a few times in the course of the 
 year ; and yet there is not one who may not find an 
 endless series of Common Objects for his microscope 
 within the limits of the tiniest city chamber. Sc 
 
 B2 
 
4 VALUE OP CAREFUL OBSEEVATION. 
 
 richly does nature teem with beauty and living marvels, 
 that even within the closest dungeon-walls a never- 
 failing treasury of science may be found by any one 
 who knovs how and where to seek for it. 
 
 It is rather a remarkable fact, that the real 
 value of observation is often in inverse ratio to the 
 multitude of the objects examined ; and we all know 
 the extreme interest which attaches itself to minute 
 and faithful records of the events which take place in 
 some very limited sphere. For example, the annals 
 of an obscure village in Hampshire have long risen 
 into a standard work, merely by virtue of the close 
 and trustworthy observations made by a resident in 
 the place ; the Tour round a Garden has enchanted 
 thousands and proved quite as attractive as any tour 
 round the world could be made \ and many most 
 curious and valuable original observations now com- 
 mitted to my note-book were made by an old lady 
 in her daily perambulation of a little scrap of a back 
 yard in the suburbs of London, barely twelve yards 
 long by four wide. 
 
 The world-famous labours of Huber on the Honey- 
 Bee, Lyonnet on the Goat Moth, and Strauss Durck- 
 heim on the Cockchaffer, are familiar to every student 
 of zoolqgy, and have done more towards advancing the 
 study of animal life than hundreds of larger works 
 
II. 
 
EARLY DISCOVERIES. 5 
 
 which embrace thousands of species in their scope. 
 There is little doubt but that if any one with an ob- 
 servant mind were to set himself to work determi- 
 natelj merely at the study of the commonest weed or 
 the most familiar insect, he would, in the course of 
 some years' patient labour, produce a work that would 
 be most valuable to science, and enrol the name of the 
 investigator among the most honoured sons of know- 
 ledge. There is not a mote that dances in the sun- 
 beam, not a particle of dust that we tread heedlessly 
 below our feet, that does not contain within its form 
 mines of knowledge as yet unworked. For if we could 
 only read them rightly, all the records of the animated 
 past are written in the rocks and dust of the present. 
 
 Up to this time the powers of the microscope, as 
 indeed is the case with all scientific inventions, are but 
 in their infant stage ; and though we have obtained 
 instruments of very great perfection, it must be re- 
 membered, that many of the earliest and greatest dis- 
 coveries were made with common magnifying glasses, 
 such as are now sold for a few pence, and which would be 
 despised by the generality of microscopical observers. 
 Indeed, there are few instances where a person so 
 minded may not possess himself of a microscope that 
 will do a considerable amount of sound work and 
 at an inappreciable cost. Many of my readers will 
 
6 EXTEMPORIZED MICROSCOPES. 
 
 doubtlessly have purchased one of those penny micro- 
 scopes, composed of a pill-box and a drop of Canada 
 balsam, which are hawked about the streets by the 
 ingenious and deserving manufacturer ; and upon a 
 pinch, a very respectable microscope may be extem- 
 porized out of a strip of card, wood, or metal, and a 
 little water. 
 
 There are, indeed, few branches of science which 
 admit of such varied modes of handling as the use of 
 the microscope. No two practical microscopists ever 
 set about their work in the same manner ; each will 
 have his own special method of manipulation, which he 
 thinks superior to any other, and each will arrive at 
 most valuable results, though by different and some- 
 times opposite roads. The scope which it gives to ready 
 invention is unlimited. Exigencies are continually 
 occurring, when the observer is deprived for the time 
 of some valuable adjunct, and is forced to invent and 
 manufacture on the spur of the moment an efficient, 
 though perhaps unsightly substitute. So well do some 
 of these make-shift contrivances answer their purpose, 
 that the inventor often prefers them to the more 
 elegant and expensive articles which are purchased 
 from the optician. 
 
 For example, I once patched up an extemporized 
 dissecting microscope out of an old retort-stand, a 
 
EXTEMPORIZED MICROSCOPES. 7 
 
 piece of cane, and six inches of elder branch, which 
 did its work as effectually as the shining-lackered brass 
 instrument which it was intended to imitate. More- 
 over, by a very simple addition of a piece of wire, it 
 answered as a movable stand for a camera lucida, 
 thus performing a duty which woula not have been 
 achieved by the expensive brass microscope of the 
 optician. All kinds of subsidiary apparatus may, in 
 like manner, be made by any one who really cares 
 about the beautiful pursuit in which he is engaged ; 
 and it is a matter of no light importance to those 
 whose purses may not be overstocked, and whose 
 hearts fail them at the price-lists of the opticians, 
 that a great proportion of the adjuncts to the 
 microscope may be manufactured at the cost of a 
 very few shillings, where the regular makers charge 
 many pounds. 
 
 The greater part of the imposing and glittering 
 paraphernalia which decorate the dealer's counter or 
 the table of the wealthy amateur may be replaced by 
 apparatus that can be made at a very trifling cost from 
 the most ordinary materials, and, for a while at least, 
 the remainder may be dispensed with altogether. It 
 is not thft wealthiest, but the acutest and most patient 
 observei who makes the most discoveries, for a work- 
 man is not made, nor even known by his tools, and a 
 
8 EXTEMPORIZED INSTRUMENTS. 
 
 good observer will discover with a common pocket- 
 magnifier many a secret of nature which has escaped 
 the notice of a whole array of dilettanti microscopists, 
 in spite of all their expensive and accurate instru- 
 ments. 
 
 It is for those who desire to be of the former class 
 that this little work is written, and in the course of 
 the following pages many examples will be given, 
 where a slight exertion of thought and ingenuity has 
 been found equivalent to the purchase of costly and 
 complicated apparatus. 
 
CHAPTER II. 
 
 SIMPLE AND COMPOUND MICROSCOPES MEASUREMENT OF POWER 
 HINTS FOR EXAMINATION DISSECTING MICROSCOPE KNIVES, 
 SCISSORS, AND NEEDLES DISSECTING TROUGHS ARRANGEMENT 
 
 OF ARTIFICIAL LIGHT INSTRUMENT MAKING DIPPING TUBES 
 
 CODDINGTON LENS COMPOUND MICROSCOPE AND APPARATUS, 
 
 MICROSCOPES may be divided into two classes, Simple 
 and Compound. The former class may contain several 
 lenses or glasses, and generally consists of a single lens ; 
 but the Compound Microscope must consist of at least 
 two glasses, the one near the object to be examined, 
 and the other near the eye. We will first mention one 
 or two forms of the Simple Microscope. 
 
 For all general purposes, the intending observer 
 can do no better than supply himself with a common 
 pocket-magnifier, which can be bought at any optician's 
 for a very small sum, containing one, two, or three 
 lenses, the last-mentioned being ^the most advisable. 
 These lenses, or " powers " as they are technically called, 
 vary in their magnifying capacities, those which in- 
 crease the size of the object to the greatest degree 
 
10 MEASUREMENT OF POWER. 
 
 being the smallest of size and the most decided in 
 their convexity, and are required to be held nearest to 
 the object. 
 
 In a work of this character it will be useless to 
 waste time and space by mentioning the abstruse 
 problems by which the construction of microscopes is 
 governed, as the full account of them would more 
 than occupy the entire book, and a compressed de- 
 scription would be wholly impossible. Suffice it to say 
 that all those who desire to study the beautiful science 
 of optics, and its application to the microscope, may 
 find full information in the larger and more scientific 
 works to which this little book is intended merely as 
 an introduction. 
 
 According to this plan, I will here mention that the 
 power of any lens is known by the distance at which 
 it must be held from the object. Thus, the inch 
 power of a compound microscope will magnify an 
 object about forty times, while the quarter-inch mag- 
 nifies not less than two hundred. Among microscopists 
 the degree to which objects are magnified is always 
 designated by " diameters, " so that if an object be 
 magnified ten diameters, we mean that it appears ten 
 times as long and as broad as it really is. The reader 
 must bear this in mind, for the glowing descriptions of 
 magnifying powers that are so often seen in advertise- 
 
HINTS FOR EXAMINATION. 11 
 
 ments are not according to diameters, but superficial 
 measure, so that a lens which magnifies ten diameters 
 is set down as one which magnifies a hundred times, 
 and one of two hundred and fifty diameters is ad- 
 vertised as magnifying five thousand times. 
 
 The pocket-magnifier has this advantage over a lens 
 fixed in a stand, that it can be turned in every direction 
 together with the object, so that the general details of 
 structure can always be better made out with one of 
 these simple instruments than with the most elaborate 
 compound microscope ever made. The higher powers 
 are only intended for the purpose of elucidating the 
 minute structure of smaller points, and are rarely em- 
 ployed until after the observer has made good use of 
 the pocket-lens. For example, in learning the struc- 
 ture of an insect, say a common gnat, it should first . 
 be thoroughly examined with the lowest power of the 
 simple lens, and afterwards by each of the higher 
 powers in succession, until the observer has obtained 
 a good general idea of the form and position of the 
 various organs, together with hints as to the portions 
 which are best adapted for the larger instruments. 
 After learning all those details, the observer next re- 
 moves a small portion of the insect, say a wing, or a 
 leg, and submits it to the lowest power of his com- 
 pound microscope, adding successively the higher powers 
 
12 DISSECTING MICROSCOPE. 
 
 until he has gone over the whole of the object. By 
 setting to work at a single subject, of whatever nature 
 it may be, and examining it first in general and after- . 
 wards by detail, the observer will find that he has 
 gained more than he would have learned by volumes 
 of reading alone. 
 
 I know of no pursuit more fascinating than this, or 
 more calculated to make him who pursues it forgetful 
 
 of time, place, hunger, and 
 cold. There is something 
 i so entrancing in the man- 
 ner in which Nature gives 
 up her wondrous secrets, 
 that the mind seems to be 
 entirely taken out of the 
 
 STAND FOR DISSECTING MICROSCOPE. 
 
 flj 
 
 as in a dream, and the day becomes too short for the 
 pleasant labour. 
 
 The simple lens already mentioned can be employed 
 in various ways, and by a little ingenuity can be made 
 serviceable either as a pocket-magnifier or a dissecting 
 microscope. The latter object is thus accomplished, 
 requiring a very trifling exercise of patience or cunning 
 of hand. Get an iron or brass rod fixed into an iron or 
 leaden foot, as seen in the engraving. Then bore a hole 
 longitudinally through a rather large wine- cork, so as to 
 
A CHEAP INSTRUMENT. 13 
 
 slide rather stiffly over the upright rod. Then take a 
 stout brass wire, twist one end of it into a spiral, 
 inclosing the cork in the centre, cut it off to the 
 required length, turn up the end of it at right angles, 
 and slightly sharpen the point. The turned-up end 
 may then be passed through a hole drilled in the handle 
 of the pocket-magnifier, and the microscope is complete. 
 The sliding cork will permit the lens to be raised to a 
 higher or lower level, while the length of horizontal 
 wire will permit the hands to be used with freedom. 
 
 In my own instrument the upright rod is simply a 
 common retort-stand, and the horizontal bar is a piece 
 of hollow elder branch lashed to one of the wire rings 
 of the stand, and carrying the lens at its extremity. 
 Moreover, by substituting a wire ring for the upturned 
 point, it will hold a camera lucida, and this is very 
 useful in sketching any object that needs rapid but 
 accurate drawing. 
 
 For those who do not possess even the small amount 
 of mechanical skill which is required for the con- 
 struction of so simple an instrument as that which has 
 just been mentioned, Ross's dissecting microscope is 
 one of the best. As may be seen, it is capable of 
 motion in every direction, and permits the lenses of 
 different powers to be fitted or secured without any 
 screwing or waste of time. This is often a considerable 
 
14 DISSECTING TOOLS. 
 
 advantage when much time is given to microscopic 
 dissection. The very best dissecting microscope that I 
 have seen was one that was employed by Dr. Acland at 
 the Anatomical Museum at Oxford, and was formed 
 something on the same principle as that mentioned 
 above. The horizontal bar was so made as to be raised 
 or lowered by turning a screw, while it was so affixed 
 to the upright bar, that it could be pushed aside in 
 
 ROSS'S DISSECTING MICROSCOPE. 
 
 order to examine the dissection with the naked eye, 
 and again drawn into its place without disturbing the 
 stand. 
 
 The only practical objection to these forms of the 
 dissecting microscope is, that they do not permit the 
 
ARRANGEMENT OF ARTIFICIAL LIGHT. 15 
 
 object to be seen by means of light thrown from 
 below, but this defect is easily remedied by cutting a 
 hole in the dissecting table and placing a mirror 
 beneath. 
 
 The tools employed for dissection need not be many 
 nor complicated, and can all be purchased for a very 
 few shillings. A very small scalpel, with a double edge, 
 is always useful, and should be extremely flat and thin 
 in the blade, as well as kept to the very acme of sharp- 
 ness by an occasional touch of a hone and razor-strap. 
 Three pairs of scissors are needful : one tolerably stout, 
 for cutting hard substances, such as the wing-cases and 
 external skeletons of beetles ; another, very long in the 
 handles, and very short and delicate in the blades, for 
 the purpose of severing minute tissues ; and the third 
 pair bent like the beak of the avocet, to enable the 
 dissector to snip off those little projections which are 
 
 continually getting in the way, and which cannot be 
 rea ched by a straight blade without running the risk of 
 damaging the dissection. 
 
 Two pairs of forceps will also be required, one 
 straight and strong, and the other fine and curved, as 
 
16 FORCEPS AND NEEDLES. 
 
 seen in the engraving. In order to insure the accu- 
 rate meeting of the points a matter of very great 
 importance the blades play upon a pin which may be 
 seen inserted near the curved extremity of the instru- 
 ment. These forceps are generally made of brass, and 
 are most useful. I generally carry a pair in my 
 pocket whenever I go into the fields, for they serve 
 to draw little insects out of their hiding places, to 
 pick up objects too minute for the fingers, and to 
 hold them while undergoing examination with the 
 pocket-magnifier. 
 
 But the sheet anchor of the microscopic dissector is 
 made of needles, which should be kept of different sizes 
 ready to hand. Fastened into wooden handles, they 
 are employed in "teasing" out delicate structures, so as to 
 separate the tissues of which they are composed without 
 tearing or cutting them. Some persons recommend 
 that a lady's crochet-case be used, which not only 
 contains a store of needles, but admits of changing the 
 point whenever needed. There are also other forms of 
 
FORMS OF NEEDLES. 17 
 
 dissecting needles manufactured, three of which are 
 represented in the illustration. 
 
 For my own part, I always find that the ivory or 
 metal handle is too heavy, and invariably employ 
 common camel's hair brush handles, in which the 
 needles can be readily fastened. Five forms are all 
 that are really useful, and many of them can be made 
 in a few minutes. In order to fix the needles firmly 
 in their handles, the following plan is the best. Get a 
 convenient handle, and wrap about a third of an inch 
 with waxed thread, leaving a little of the wood pro- 
 jecting without any thread. Take the needle, break 
 it off" to a convenient length, push the point into 
 the handle so as to make a hole, reverse it, and 
 with a pair of pliers drive the needle well into the 
 handle, the thread preventing the wood from splitting, 
 Now trim the wood to a point, so as to make it all 
 look neat, and a light handy instrument is at once 
 made. 
 
 The five forms are employed for different purposes. 
 The first, No. 1, is a short thick needle, set in a large 
 handle, and used for boring holes in wood, mica, cork, 
 or wax, as may be required. It is also useful for making 
 the holes in new handles. No. 2 is a rather fine, straight 
 needle, and is the most generally useful of the set. 
 Several of these should be made of different degrees 
 c 
 
18 FORMS OF NEEDLES. 
 
 of fineness. No. 3 is a slightly bent needle, valuable 
 in getting at tissues that lie hidden under other sub- 
 stances. Several of these should be made, bent at 
 different curvatures, and of different strength. No. 4 
 is occasionally useful for pulling thready tissues aside 
 in order to permit another instrument to be used ; 
 and No. 5 is required for lifting a delicate structure 
 without injuring it. The reader will observe that it 
 has no point, but that its 
 extremity is defended by a 
 little knob. I may also . 
 mention that it will be an 
 / /- <4i((( , =13 improvement if the fine 
 
 f <Jffl> ~4 scissors have also one blade 
 
 r terminated by a little knob. 
 There is no need for 
 
 making a great supply of these instruments before 
 commencing work. I always used to fit up several 
 of 2 and 3, and to make the others as they are 
 required. I can strongly recommend these simple 
 little instruments, as they are very light, and are 
 little liable to injury. 
 
 The other appliances for insect dissection are equally 
 simple. 
 
 As all delicate structures are dissected under fluid, a 
 shallow glass dish is required. My own are simple flat 
 
 
DISSECTING TROUGHS. 19 
 
 round glass cells, about one inch in depth and four in 
 diameter. For very large obj ects, a dish of corresponding 
 length is of course required. This is plentifully filled 
 with water or spirit generally a mixture of the two 
 and the dissection is sunk to the bottom by being 
 fastened to a flat cork attached to a strip of sheet lead. 
 The simplest way of making this loaded cork is to cut 
 a piece of flat cork to the required size, lay it on a 
 piece of sheet lead, cut the lead rather wider than the 
 cork, turn it up over the edge, and fasten it with a few 
 blows of a hammer. 
 
 Some persons prefer to make a very shallow dish of 
 lead, and to pour melted wax into it. so as to fix the 
 object upon the wax. I, however, prefer the cork, as 
 the pins are apt to break away from the wax. The cork 
 should be very fine-grained, as if the holes are large 
 and deep, the pin is sure to plunge through the dis- 
 section, carrying with it the tip of the forceps, and 
 thereby doing irremediable damage. 
 
 Of course the whole affair must be set in a good 
 light, or the dissection will be impracticable. Daylight 
 is by far the best, for I always find that by artificial 
 light the shadows are thrown so perplexingly that it 
 is almost impossible to make out the real structure 
 of a delicate object, and an important tissue may 
 be broken under the impression that it is but a 
 c2 
 
20 
 
 ARRANGEMENT OF LIGHT. 
 
 shadow. If, however, artificial light must be used, 
 the accompanying illustration will show the manner 
 of arranging it. 
 
 The light is thrown perpendicularly upon the object 
 by means of a common " condenser," and the hands 
 
 DISSECTING UNDER WATER. 
 
 are so placed as to avoid getting in the way of the 
 light. In practice it will be found very useful to 
 support the hands by means of a book or piece of wood 
 on each side of the glass cell, as the handling becomes 
 
 
INSTRUMENT MAKING. 21 
 
 very awkward and fatiguing without some such pre- 
 caution. The best support is made of a thick piece of 
 board of the same height as the edge of the glass cell, 
 flat for two inches or so, and then sloped away so as to 
 form an inclined plane. 
 
 Great care must be taken with the points of the 
 needles that they are perfectly smooth and polished, as 
 if there is the least roughness they will hitch in the 
 more delicate structures and tear them woefully. Also, 
 the needles should not be too long, as the elasticity of 
 the steel is apt to make them spring when pressed. 
 The length given in the engraving is amply sufficient. 
 The bending of the needles is easily accomplished by 
 holding them in a candle until red-hot, when they can 
 readily be bent into any form that is desired. By this 
 mode of treatment they become soft and yielding, but 
 can be immediately restored to their original hardness 
 by reheating, and then plunging them into cold water. 
 A spirit lamp will serve better than a candle, as it does 
 not blacken the needle, and permits the dissector to 
 work more freely. 
 
 A large supply of variously sized pins should be at 
 hand, some of tolerable size, a great many minikins, 
 and a box of fine entomological pins. I always have a 
 loaded cork close to the dissecting cell, the cork being 
 filled with pins of different sizes, graduated according 
 
22 INSTRUMENT MAKING. 
 
 to their position, so that they can be taken at any 
 moment without search or disturbance. These are 
 employed for fastening the object to the loaded cork in 
 the cell, and also for keeping aside the various structures 
 as they are dissected out. The number of pins that is 
 required is really remarkable, for in the ordinary dis- 
 section of an insect some fourteen or fifteen pins will 
 gradually be used. 
 
 . A very fine-nosed syringe is a most useful article, but 
 its place can be very well supplied by glass tubes made 
 after the following fashion. 
 
 Get a glass tube or two from the chemist the 
 diameter is of little consequence, provided that the 
 glass be of soft quality light the spirit lamp, and hold 
 one of these tubes by the ends, keeping the centre over 
 the flame and turning it continually to prevent the glass 
 from cracking. Lower it gradually into the flame, 
 until it becomes of a bright red heat and quite soft. 
 Then draw the two ends rapidly asunder, ancl there will 
 be two tubes, each ending in a point of very thin glass. 
 
 Break away the extremity of the point, and you will 
 have a tube with a very fine outlet. Of course if you 
 want a large diameter, you have only to break away the 
 glass a little higher. 
 
 The broken end should then be held for a moment 
 in the margin of the flame so as to round its sharp edges. 
 
DIPPING TUBES. 
 
 23 
 
 These tubes are extremely useful, being employed 
 when very fine for washing aside any tissue that is too 
 
 DIPPING TUBES AND MODE OF USING. 
 
 delicate to be handled with the steel, and are used by 
 putting the large end into the mouth, drawing the 
 liquid into them by suction, and expelling it by the 
 breath. 
 
24 CODDINGTON LENS. 
 
 These and similar tubes are also useful for "dip- 
 ping " out minute organisms from the water in which 
 they live, and are therefore termed " dipping tubes." 
 Several forms of dipping tubes are represented in the 
 engraving, and the way that they are used is by pressing 
 the finger firmly on the top, plunging the other end of 
 the tube into the water, placing it close to the object, 
 and then suddenly removing 
 the finger, when the water will 
 immediately rush into the 
 tube, carrying with it the 
 desired object. Of all these 
 forms, that which is marked d 
 is perhaps the most generally 
 useful. The reader will see 
 that they can be made of any 
 shape or size, according to the 
 occasion. 
 
 CODDINGTON LENS. Before bidding farewell to 
 
 the simple lens, we must glance at a very useful and 
 portable form, which can be carried in the waistcoat 
 pocket, and is quite as powerful and welldefining a 
 magnifier as many compound microscopes. It is 
 termed the " Coddington " Lens, and is nothing more 
 than a polished sphere of glass, with a deep groove 
 out round its circumference and the hollow filled with 
 
STANHOPE LENS. 25 
 
 black cement. In the illustration one of these useful 
 little instruments is depicted, together with a section 
 of the Scime, showing the manner in which the rays of 
 light are forced to pass through the lens under similar 
 circumstances. The "field" of this little microscope 
 is very flat, and the definition is good in whatever way 
 it may be held. 
 
 For the sake of convenient holding, the handle 
 should be three or four times as long as that of the 
 figure ; and after a little practice the observer will set 
 great value on this lens. There is another lens which 
 bears some external resemblance to the Coddington, 
 and is called by the name of the " Stanhope " lens, 
 against which the reader is hereby warned. Dealers 
 often try to induce their chance customers to purchase 
 the Stanhope lens, and the reader may distinguish 
 between them by the fact that both ends of the 
 Coddington lens are alike ; whereas in the Stanhope, one 
 has twice the convexity of the other. The Coddington 
 is extremely useful for a cursory examination of any 
 object that may be found in the field, as its great power 
 will enable the observer to make out the details of any 
 minute structure, and to decide whether the object will 
 be worth bringing home and placing under the com- 
 pound microscope. 
 
26 COMPOUND MICROSCOPE. 
 
 HAVING thus given some little attention to the simple 
 microscope, we will pass to the more complicated 
 apparatus termed the COMPOUND MICROSCOPE. 
 
 This invaluable instrument is made in various ways, 
 the chief essential being that one glass is placed close 
 to the object, and the other near the eye. In former 
 days, the tube that contained these glasses was several 
 feet in length, so that the whole affair might easily be 
 mistaken for a great astronomical telescope. Into the 
 details of structure I do not intend co enter, nor to 
 describe the varieties of compound microscopes that 
 are constantly produced by different makers, as the 
 whole of the work would be absorbed in that one 
 department alone. The accuracy with which these 
 instruments are made is almost fabulous, and the 
 number and beauty of their accessories is so great, 
 that the first-rate compound microscope is said to 
 be the only instrument in the world where the per- 
 formance equals the theory on which it is made. 
 
 Such an instrument is beyond the reach of most 
 persons, costing from forty or fifty pounds and upwards, 
 and is therefore quite unsuited to the purposes of the 
 present work. There is, however, a compound micro- 
 scope which is a really admirable instrument, giving a 
 flat though small field, great magnifying powers, clear 
 definition, and is quite achromatic, i.e. without those 
 
EDUCATIONAL MICROSCOPE. 
 
 27 
 
 fringes of rainbow colouring which are always seen 
 surrounding the objects in inferior microscopes. 
 
 It is furnished with three powers, named the inch, 
 half-inch, and quarter-inch object-glasses, has a sliding 
 stage for the purpose of conveniently moving the object 
 
 EDUCATIONAL MICROSCOPE. 
 
 ^rns on two pivots so as to suit the position of the 
 head, the " body " or tube where the glasses are set 
 is moved to and from the object by large and fine 
 
28 PARTS OF THE MICROSCOPE. 
 
 screws, called technically the " quick and slow motion," 
 and is also supplied with dissecting forceps, a stage 
 forceps, and a " live-box," all fitting into a neat 
 mahogany box, so managed that supplementary appur- 
 tenances can be packed when obtained. I have sub- 
 jected this instrument to careful testing, and can 
 report in very high terms of it. In fact, for every 
 purpose except that of scientific controversy, it is quite 
 as good an instrument as any one could wish to see, 
 and only costs three guineas ; not half the price of a 
 single object-glass belonging to the larger microscopes. 
 
 As the various objects here mentioned require some 
 little explanation, we will treat of them separately. 
 
 The lenses constituting the three powers screw on to 
 the lower extremity of the tube, and are so made that, 
 in order to obtain a higher power, all that is needed is 
 to employ all the three, which screw into each other ; 
 two giving a less power, and one the least of all. The 
 reader will see the convenience of this arrangement. 
 When an object has been well examined with the lowest 
 power, a second can be added, and the large screw 
 turned so as to bring the glass nearer to the object, 
 which is sure of being in the exact field of the glass. 
 This is of no small consequence, as the hunting for a 
 little object on a large slide under a high power is one 
 of the most provoking of chases, and often forces the 
 
HANDLING THE MICROSCOPE. 29 
 
 observer to remove the high power, replace it by a lower, 
 find the object, get it in the centre of the field, change 
 the glass again, and then bring it down upon the object. 
 The highest power should always be nearest the object. 
 
 On the stage, i.e. the flat plate of metal immediately 
 under the object-glass, may be seen the raised ledge 
 against which the glass slide holding the object is laid, 
 and which, by sliding up and down the stage, carries 
 the object with it. This movement is necessary, in 
 order to bring every portion of a large object into the 
 field of the microscope. The large-headed screws which 
 form the quick movement or coarse adjustment are 
 seen just behind the stage, and raise or depress the 
 tube by means of a rack and pinion movement. The 
 screw of the fine adjustment is seen just above the 
 horizontal rim, into which the body is fixed, and acts 
 by means of a screw working against a spring. 
 
 The mirror, which may be seen below the stage, is so 
 fitted that it can be turned in any direction, so as to 
 throw the rays of light straight or obliquely through 
 the object, either method being equally useful under 
 different circumstances. The heavy stand is made of 
 iron, and affords a firm and solid support to the 
 instrument, a matter of no trifling consequence when 
 the reader reflects that motion is magnified as well as 
 substance, so that if the instrument trembles in the 
 
30 MIRROR AND FORCEPS. 
 
 least degree, the object becomes almost invisible, seeming 
 to flutter before the eyes of the observer like the 
 whirring wings of a hovering fly. 
 
 All these portions of the instrument are affixed to 
 the stand, but there are other parts of the apparatus 
 which are furnished and used separately. 
 
 The dissecting forceps have already been described 
 and figured on page 12, so that no further mention is 
 needful. The stage forceps are of a very different 
 
 STAGE FORCEPS. 
 
 appearance, as may be seen by the accompanying 
 illustration. 
 
 The dark-coloured pin at the bottom fits into a hole 
 in one corner of the stage, in which it can be turned 
 freely. A brass socket is hinged to the pin, and bears 
 a steel bar, which passes horizontally through it, and 
 carries at one end the forceps, and at the other end is 
 either sharply pointed, or fitted with a brass cap, into 
 which a piece of cork is firmly pressed. The reader 
 will see that this instrument is capable of being turned 
 in every direction, and as the horizontal bar revolver 
 freely in the socket, any object held in the forceps can 
 
LIVE-BOX. 31 
 
 be turned round so as to afford a view of every side. 
 To hold the object, one of the pins in the forceps blades 
 is pressed, which separates one blade from the other, 
 and when the pressure is removed, the elasticity of the 
 blades, which are made of steel, brings the points 
 together, and holds the object firmly between them. 
 
 VAHLEY'S ANIMALCULE CAGE, OB LIVE-BOX. 
 
 Under a low power the stage forceps are almost indis- 
 pensable, but for the higher can hardly be employed 
 at all, as the light and the focussing are both so difficult 
 of management that the comparatively coarse forceps 
 cannot be successfully used except by a very practised 
 hand. 
 
 The Live-Box or Animalcule cage is also a most use- 
 ful, and in fact a necessary part of the apparatus. In 
 the illustration it is shown, together with a section 
 exhibiting the details of its structure. 
 
32 USE OF THE LIVE-BOX. 
 
 It consists of two brass tubes, sliding in eacli other, 
 and each being furnished at the top with a plate of 
 glass, so arranged that when the upper tube is pressed 
 down to the fullest extent, the glass plates are all but 
 in contact with each other. This instrument is used 
 for examining animalcules, microscopic plants, and 
 other substances, and is very simple in its operation. 
 The upper tube or cap is removed, and a little drop of 
 water containing the object is placed on the glass of 
 the lower tube. The cap is then replaced, and as it is 
 pressed down the drop of water is proportionately 
 flattened. 
 
 The live-box represented in the engraving is of a 
 superior description, and is so managed that the glass 
 of the lower tube is thick, and has a groove running 
 round it like the moat surrounding an old castle. The 
 reason of this arrangement is, that the superabundant 
 fluid only runs over the glass into the groove, while 
 the objects remain in their places. A B is the flat 
 brass plate on which the lower tube is fastened, d is 
 the brass-grooved ledge of the tube, c is the thick 
 glass top of that tube, and a is the glass cover of the 
 cap, whose sides are represented by the black perpen- 
 dicular lines outside the tube. 
 
 This kind of cage is especially valuable, as the cap 
 can be fitted with glasses of different strength, so 
 
COMPBESSORIUM. 
 
 33 
 
 that it can either be employed in the investigation of 
 microscopic animalcules or in flattening sundry sub- 
 stances which need pressure to bring out their details. 
 There is another instrument made for this purpose, 
 
 CONDENSER. 
 
 termed a compressorium," but in careful and steady 
 hands the live-box will answer nearly as well. 
 
 A condenser" is generally supplied with the 
 
34 CONDENSER. 
 
 microscope, and, as its name imports, is used for 
 condensing the light upon an opaque object. It is 
 mounted in various ways, sometimes fitting into a 
 socket on the stage like the stage forceps, but generally 
 on a separate stand as in the engraving. The upright 
 rod consists of two tubes one within the other, which 
 draw out in telescopic fashion, so that the " bull's-eye " 
 lens can be raised to any convenient height. Some little 
 practice is required to use this instrument properly, 
 but when rightly managed it is quite invaluable, 
 bringing out effects which would otherwise be totally 
 invisible. Indeed, with the exception of those objects 
 which are viewed by polarized light, there are none 
 which have so splendid an effect as those which are 
 illuminated by the condenser. So large an amount of 
 light is concentrated in so small a space that when it 
 is refracted from hairs, feathers, or scales, especially the 
 wing-scales of several insects, the whole field of the 
 microscope seems to be filled with resplendent gems, 
 flashing with a radiance that is almost painful in its 
 intensity. 
 
 To the under surface of the stage is generally affixed 
 a circular plate of metal, pierced with holes of various 
 diameters, and called a " diaphragm." It is a useful 
 instrument, and is employed for modifying the amount 
 of light which is thrown by the mirror through the 
 
DIAPHRAGM. 35 
 
 hole in the stage. By turning this plate the holes can 
 be successively brought under the hole in the stage, 
 and their centres are made to coincide with the centre 
 of the object-glass by a little spring catch which is 
 
 THE DIAPHRAGM. 
 
 seen on the left hand of the engraving, and which fits 
 slightly into a notch. As a general rule, the smaller 
 holes should be used with the higher powers, as the 
 " pencil " of light ought to be rather smaller than the 
 diameter of the object-glass. Should the observer 
 wish to shut off all the light, he has only to turn the 
 diaphragm beyond the smallest hole, when the blank 
 portion of the metal will pass over the hole in the 
 stage and effectually answer that purpose. 
 
 This little preliminary dissertation is rather un- 
 interesting, but is needful in order to enable the reader 
 to comprehend that which is to follow. 
 
CHAPTEE III. 
 
 VEGETABLE CELLS AND THEIR STRUCTURE STELLATE TISSUES 
 SECONDARY DEPOSIT DUCTS AND VESSELS WOOD-CELLS 
 STOMATA, OR MOUTHS OF PLANTS THE CAMERA LUCIDA, AND 
 MODE OF USING SPIRAL AND RINGED VESSELS HAIRS OP 
 PLANTS RESINS, SCENTS, AND OILS BARK CELLS. 
 
 WE will now suppose the young observer to have 
 obtained a microscope, and learned the use of its 
 various parts, and will proceed to work with it. As 
 with one or two exceptions, which are only given for 
 the purpose of further illustrating some curious struc- 
 ture, the whole of the objects figured in this work can 
 be obtained without any difficulty, the best plan will 
 be for the reader to procure the plants, insects, &c. from 
 which the objects are taken, and follow the book with 
 the microscope at hand. It is by far the best mode of 
 obtaining a systematic knowledge of the matter, as the 
 quantity of objects which can be placed under a mi- 
 croscope is so vast, that without some guide the tyro 
 flounders hopelessly in the sea of unknown mysteries, 
 and often becomes so bewildered that he gives up the 
 
VEGETABLE CELLS. 37 
 
 study in despair of ever gaining any true knowledge 
 of it. I would therefore recommend the reader to 
 work out the subjects which are here mentioned, and 
 then to launch out for himself in the voyage of dis- 
 coveries. I speak from experience, having myself 
 known the difficulties under which a young and in- 
 experienced observer has to labour in so wide a field, 
 without any guide to help him to set about his work 
 in a systematic manner. 
 
 The objects that can be easiest obtained are those of 
 a vegetable nature, as even in London there is not a 
 square, an old wall, a greenhouse, a florist's window, or 
 even a greengrocer's shop, that will not afford an ex- 
 haustless supply of microscopic employment. Even 
 the humble vegetables that make their daily appearance 
 on the dinner-table are highly interesting ; and in a 
 crumb of potato, a morsel of greens, or a fragment of 
 carrot, the enthusiastic observer will find occupation 
 for many hours. 
 
 Following the best examples, we will commence at 
 the beginning, and see how the vegetable structure is 
 built up of tiny particles, technically called " cells." 
 
 That the various portions of every vegetable should 
 be referred to the simple cell is a matter of some sur- 
 prise to one who has had no opportunity of examining 
 the vegetable structure, and indeed it does seem more 
 
38 FORM OF CELLS. 
 
 than remarkable that the tough, coarse bark, the 
 hard wood, the soft pith, the green leaves, the delicate 
 flowers, the almost invisible hairs, and the pulpy fruit 
 should all start from the same point, and owe their 
 origin to the simple vegetable cell. This, however, is 
 the case ; and by means of a few objects chosen from 
 different portions of the vegetable kingdom, we shall 
 obtain some definite idea of this curious phenomenon. 
 On plate 1, fig. 1, may be seen three cells of a some- 
 what globular form, taken from the common straw- 
 berry. Any one wishing to examine these cells for 
 himself may readily do so by cutting a very thin slice 
 from the fruit, putting it on a slide, covering it with a 
 piece of thin glass, which may be cheaply bought at 
 the optician's, together with the glass slides on which 
 the objects are laid, and placing it under a power of 
 two hundred diameters. Should the slice be rather 
 too thick, it may be placed in the live-box and well 
 squeezed, when the cells will exhibit their forms very 
 distinctly. In their primary form, the cells seem to 
 be spherical ; but as in many cases they are pressed 
 together, and in others are formed simply by the pro- 
 cess of subdivision, the spherical form is not very often 
 seen. The strawberry, being a soft and pulpy fruit, 
 permits the cells to assume a tolerably regular form, 
 and they consequently are more or less globular. 
 
STRUCTURE OF THE CELL. 39 
 
 Where the cells are of nearly equal size, and are 
 subjected to equal pressure in every direction, they 
 force each other into twelve-sided figures, having the 
 appearance under the microscope of flat six-sided forms. 
 Fig. 8, taken from the stem of a lily, is a good example 
 of this form of cell, and many others may be found in 
 various familiar objects. 
 
 We must here pause for a moment to define a cell 
 before we proceed farther. 
 
 The cell is a closed sac or bag formed of a substance 
 called from its function " cellulose," and containing 
 certain fluid contents as long as it retains its life. In 
 the interior of the cell may generally be found a little 
 dark spot, termed the "nucleus," and which may be 
 seen in fig. 1, to which we have already referred. The 
 object of the nucleus is rather a bone of contention 
 among the learned, but the best authorities on this 
 subject consider it to be the vital centre of the 
 cells, to and from which tends the circulation of the 
 contained fluid. In point of fact, the nucleus may be 
 considered as the heart and brain of the cell. On 
 looking a little closer at the nucleus, we shall find 
 it marked with several small light spots, which are 
 termed " nucMoli." 
 
 On the same plate (fig. 2) is a pretty group of cells 
 taken from the internal layer of the buttercup leaf, 
 
40 PITTED CELLS. 
 
 and chosen because they exhibit the series of tiny and 
 brilliant green dots to which the colour of the leaf 
 is due. The technical name for this substance is 
 " chlorophyll," or " leaf-green," and it may always be 
 found thus dotted in the leaves of different plants, the 
 dots being very variable in size, number, and arrange- 
 ment. 
 
 In the centre of the same plate (fig. 12) is a group 
 of cells from the pith of the elder-tree. This speci- 
 men is notable for the number of little " pits " which 
 may be seen scattered across the walls of the cells, 
 and which resemble holes when placed under the 
 microscope. In order to test the truth of this ap- 
 pearance, the specimen was coloured blue by the 
 action of iodine, when it was found that the blue 
 tint spread over the pits together with the cell-walls, 
 showing that the membrane is continuous over the 
 pits. 
 
 Fig. 7 exhibits another form of cell, taken from the 
 Sparganium, or bur-reed. These cells are tolerably 
 equal in size, and have assumed a squared shape. 
 They are obtained from the lower part of the leaf. 
 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 squared facets of the compound eyes 
 
STELLATE TISSUE. 41 
 
 belonging to insects and crustaceans. In a future 
 page these will be separately described. 
 
 Sometimes the cells take most singular and un- 
 expected shapes, several examples of which will be 
 briefly noticed. 
 
 In certain loosely made tissues, such as are found 
 in the rushes and similar plants, the walls of the cells 
 grow very irregularly, so that they push out a number 
 of arms which meet each other in every direction, and 
 assume the peculiar form which is termed "stellate," 
 or star-shaped tissue. Fig. 3 shows a specimen of 
 stellate tissue taken from the seed-coat of the privet, 
 and rather deeply coloured, exhibiting strongly the 
 beautiful manner in which the various arms of the 
 stars meet each other. A smaller group of stellated 
 cells may be seen in fig. 4, taken from the stem of a 
 large Rush, and exemplifying the peculiarities of the 
 structure. 
 
 The reader will at once see that this mode of forma- 
 tion leaves a vast number of interstices, and gives great 
 strength with little expenditure of material. In water- 
 plants, such as the reeds, this property is extremely 
 valuable, as they must be greatly lighter than the 
 water in which they live, and at the same time must 
 be endued with considerable strength, in order to resist 
 its pressure. 
 
42 ELONGATED CELLS. 
 
 A less marked example of stellate tissue is given 
 in fig. 11, where the cells are extremely irregular in 
 their form, and do not coalesce throughout. This 
 specimen is taken from the pithy part of a Bulrush. 
 There are very many other plants from which the stel- 
 late cells may be obtained, among which the Orange 
 affords very good examples in the so-called "white" 
 that lies under the yellow rind, a section of which may 
 be made with a very sharp knife, and laid under the 
 field of the microscope. 
 
 Looking towards the bottom of the plate, and refer- 
 ring to fig. 27, the reader will observe a series of nine 
 elongated cells, placed end to end, and dotted profusely 
 with chlorophyll. These are obtained from the stalk 
 of the .common chickweed. Another example of the 
 elongated cell is seen in fig. 14, which is a magnified 
 representation of the rootlets of wheat. Here the cells 
 will be seen in their elongated state, set end to end, 
 and each containing its nucleus. On the left hand of the 
 rootlet (fig. 13) 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 carmine, and had taken up a con- 
 siderable amount of the colouring substance. Many 
 experiments on this subject were made by the Kev. Lord 
 S. G. Osborne, and may be seen at full length in the 
 pages of the Microscopical Journal, the subject being too 
 
MULTIPLICATION OF CELLS. 43 
 
 large to receive proper treatment in the very limited 
 space which can here be given to it. 
 
 One very remarkable point is, that the carmine was 
 always found to be taken most plentifully into the 
 nucleoli, and to give them a very deep colouring. 
 These specimens exhibited the phenomenon which has 
 already been casually mentioned, that the rotation of 
 the granules in the interior of the cell takes place to 
 and from the nuclei. 
 
 Fig. 9 on the same plate exhibits two notable pecu- 
 liarities the irregularity of the cells, and the copiously 
 pitted deposit with which they are covered. The irre- 
 gularity of the cells is mostly produced by the way in 
 which the multiplication takes place, namely, by division 
 of the original cell into two or more portions, so that 
 each portion takes the shape which is assumed when a 
 component part of the parent cell. In this case the 
 cells are necessarily very irregular, and when they are 
 compressed from all sides, they form solid figures of 
 many sides, which, when cut through, present a flat 
 surface marked with a variety of irregular outlines. 
 This specimen is taken from the rind of a Gourd. 
 
 The "pitted" 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 walls, and which 
 is perforated with a number of very minute holes called 
 
44 SECONDARY DEPOSIT. 
 
 "pits." This substance is called "secondary deposit." 
 That these pits do not extend through the real cell 
 wall has already been shown in fig. 12, p. 29. 
 
 This secondary deposit I pray the reader's pardon 
 for using such language, but there is no alternative is 
 exhibited in more modes than one. In some cases it is 
 deposited in rings round the cell, and is clearly placed 
 there for the purpose of strengthening the general 
 structure. Such an example may be found in the 
 Mistletoe, tig. 5, where the secondary deposit has formed 
 itself into clear and bold rings, that evidently give con- 
 siderable strength to the delicate walls which they 
 support. Fig. 10 gives another good instance of a 
 similar structure ; differing from the preceding speci- 
 men in being much longer and containing a greater 
 number of rings. This object is taken from an anther 
 of the Narcissus. Among the many plants from which 
 similar objects may be obtained, the Yew is, perhaps, 
 one of the most prolific, as ringed wood-cells are abun- 
 dant in its formation, and probably aid greatly in giving 
 to the wood the strength and elasticity which have long 
 made it so valuable in the manufacture of bows. 
 
 Before taking leave of the cells and their remarkable 
 forms, we will just notice one example which has been 
 drawn in fig. 6. This is a congeries of cells, containing 
 their nuclei, starting originally end to end, but swelling 
 
DUCTS AND VESSELS. 45 
 
 and dividing at the top. This is a very young group 
 of cells from the inner part of a Lilac bud, and is 
 here introduced for the purpose of showing the great 
 similarity of all vegetable cells in their earliest stages 
 of existence. No one who did not know the history of 
 chat little group could imagine what would be its per- 
 fected condition, for it might either spread itself into a 
 leaf, or extend itself into a flower, or end its days as a 
 hair, for all the indications that it affords of its future. 
 
 Having now examined the principal forms of cells, 
 we arrive at the " ducts," a term which is applied to 
 those long and delicate tubes which are formed of a 
 number of cells set end to end, their walls of separation 
 being absorbed. At first the young microscopist is apt to 
 puzzle himself between ducts and vessels, but may easily 
 set himself right by remembering that ducts are squared 
 at their ends, and vessels or wood-cells are pointed. 
 
 In fig. 19 the reader will find a curious example of 
 the "dotted duct," so called from the multitude of little 
 markings that cover its walls, and which are arranged 
 in a spiral order. Like the pits and rings already men- 
 tioned, the dots are composed of secondary deposit in the 
 interior of the tube, and vary very greatly in number, 
 function, and dimensions. This example is taken from 
 the wood of the willow, and is remarkable for the ex- 
 treme closeness with which the dots are packed together. 
 
46 NETTED DUCTS AND OIL-CELLS. 
 
 Immediately on the right hand of the preceding 
 figure may be seen another example of a dotted duct 
 (fig. 20), taken from a Wheat stem. In this instance the 
 cells are not nearly so long, but are wider than in the 
 preceding example, and are marked in much the same 
 way with a spiral series of dots. About the middle of 
 the topmost cell is shown the short branch by which it 
 communicates with the neighbouring duct. 
 
 Fig. 23 exhibits a duct taken from the common 
 Carrot, in which the secondary deposit is placed in such 
 a manner as to resemble a net of irregular meshes 
 wrapped tightly round the duct. For this reason it is 
 termed a " netted, duct." A very curious instance of 
 these structures is given in fig. 26, at the bottom of 
 the plate, where are represented two small ducts from 
 the wood of the Elm. One of them that on the left 
 hand is wholly marked with spiral deposit, the spires 
 being complete j while in the other instance the spiral is 
 comparatively imperfect, and the cell walls are marked 
 with pits. If the reader would like to examine these 
 structures more attentively, he will find plenty of them 
 in many familiar garden vegetables, such as the common 
 Eadish, which is very prolific in these interesting 
 portions of vegetable nature. 
 
 There is another remarkable form in which this 
 secondary deposit is sometimes arranged, that is well 
 
SCALARIFORM TISSUE. 47 
 
 worthy our notice. An example of this structure is 
 given in fig. 18, taken from the stalk of the common 
 Fern or Brake. It is also found in very great perfec- 
 tion in the Vine. On inspecting the illustration, the 
 reader will observe that the deposit is arranged in 
 successive bars or steps, like those of a winding 
 staircase. In allusion to the ladder-like appearance 
 of this formation, it is called " scalariform," or ladder- 
 like form. 
 
 In the wood of the Yew, to which allusion has already 
 been made, there is a very peculiar structure, found 
 only in those trees that bear cones, and therefore termed 
 the coniferous glandular structure. Fig. 16 is a section 
 of a common Cedar pencil, the wood, however, not being 
 that of the true cedar, but of a species of fragrant 
 Juniper. This specimen shows all the peculiar forma- 
 tion which has just been mentioned, and in addition 
 exhibits the situation of the oil-cells which give to the 
 wood its well-known fragrance. 
 
 Any piece of deal or pine will exhibit the same 
 peculiarities in a very marked manner, as is seen in fig. 
 24. A specimen may be readily obtained by making a 
 very thin shaving with a sharp plane. In this example, 
 the deposit has taken a partially spiral form, and the 
 numerous circular pits with which it is marked are 
 only in single rows. In several other specimens of 
 
18 WOOD- CELLS. 
 
 coniferous woods, such as the Araucaria, or Norfolk 
 Island Pine, there are two or three rows of pits. 
 
 A peculiarly elegant example of this spiral deposit 
 may be seen in the wood of the common Yew, fig. 17. 
 If an exceedingly thin section of this wood be made, 
 the very remarkable appearance will be shown which is 
 exhibited in the illustration. The deposit has not only 
 assumed the perfectly spiral form, but there are two 
 complete spirals, arranged at some little distance from 
 each other, and producing a very pretty effect when 
 seen through a good lens. 
 
 The pointed, elongated shape of the wood-cells, is 
 very well shown in the common Elder-tree (see fig. 15). 
 In this instance the cells are without markings, but in 
 general they are dotted like fig. 21, an example cut 
 from the woody part of the Chrysanthemum stalk. 
 This affords a very good instance of the wood-cell, as 
 its length is considerable, and both ends perfect in shape. 
 On the right hand of the figure is a drawing of the wood- 
 cell found in the Lime-tree (fig. 22), remarkable for 
 the extremely delicate spiral markings with which it is 
 adorned. In these wood-cells the secondary deposit is 
 so plentiful, that the original membranous character of 
 the cell- walls is entirely lost, and they become elon- 
 gated and nearly solid cases, having but a very small 
 cavity in their centre. It is to this deposit that the 
 
STOMATA, OR MOUTHS OF PLANTS. 49 
 
 hardness of wood is owing, and the reader will easily 
 see the reason why the old wood is so much harder 
 than the young and new shoots. In order to permit 
 the passage of the fluids which maintain the life of the 
 part, it is needful that the cell wall be left thin and 
 permeable in certain places, and this object is attained 
 either by the "pits" described on page 29, or by the 
 intervals between the spiral deposit. 
 
 At the right-hand bottom corner of Plate I. (fig. 20), 
 may be seen a prettily marked object, which is of some 
 interest. It is a slice stripped from the outer coat of the 
 Holly-berry, 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 our- 
 selves, though their respiration is slower. Among the 
 mass of net-like cells may be seen three curious objects, 
 bearing a rather close resemblance to split kidneys. 
 These are the mouths, or " stomata " as they are scien- 
 tifically called, scientific people always liking to use a 
 long Greek word where a short English one would do 
 as well. 
 
 In the centre of the mouths may be seen a dark spot, 
 which is the aperture through which the air communi- 
 cates with the passages between the cells in the interior 
 of the structure. In the flowering plants their shape 
 is generally rounded, though they sometimes take ft 
 
50 POSITION OP STOMATA. 
 
 squared form, and they regularly occur at tne meeting 
 of several surface cells. Their edges are protected by 
 certain "pore-cells," or "guard-cells," so called from 
 their function, which, by their change of form, cause 
 the mouth to open or shut, as is best for the plant. 
 In young plants these guard-cells are very little below 
 the surface of the leaf or skin, but in others they are 
 sunk quite beneath the layer of cells, forming the outer 
 coat of the tissue. There are other cases, where they 
 are slightly elevated above the surface. 
 
 Stomata are found chiefly in the green portions of 
 plants, and are most plentiful on the under side of 
 leaves. It is, however, worthy of notice, that when an 
 aquatic leaf floats on the water, the mouths are only 
 to be found on the upper surface. These curious and 
 interesting objects are to be seen in many structures 
 where we should hardly think of looking for them, for 
 they may be found existing on the delicate skin which 
 envelops the kernel of the common walnut. As might 
 be expected, their dimensions vary with the character 
 of the leaf on which they exist, being large upon the 
 soft and pulpy leaves, and smaller upon those of a 
 hard and leathery consistence. The reader will find 
 ample amusement, and will gain great practical know- 
 ledge of the subject, by taking a plant, say a tuft of 
 Groundsel, and stripping off portions of the external 
 
CAMERA LUCIDA. 
 
 skin or " epidermis " from, the leaf or stem, &c., so as to 
 note the different sizes and shapes of the stomata. 
 
 Let me here notice that the young microscopist 
 should always sketch every object which he views, as 
 
 CAMERA LUCIDA. 
 
 he will thus obtain a far clearer and more lasting 
 impression of the subject than can be gained merely 
 by examining one object after another. By far the 
 
52 USE OF THE CAMERA. 
 
 best mode of sketching is to use the Camera Lucida, a 
 figure of which is given on the preceding page. 
 
 It consists of a prism of glass, affixed to a brass tube, 
 which is slid upon the eye-piece of the microscope, after 
 removing the perforated cap. The microscope is then 
 laid horizontally, and the eye applied to the little 
 oblong aperture, as seen in the figure. A piece of 
 white paper is then laid immediately below the eye- 
 piece, where the large arrow is seen in the illustration, 
 and the object will apparently be thrown upon the 
 paper. A hard and very sharply pointed pencil should 
 then be taken, and the outline of the object traced 
 upon the paper. 
 
 On the first two or three trials, the beginner will 
 perhaps fail utterly, as there is some difficulty in seeing 
 the object and the pencil simultaneously, but with a 
 little practice success is certain. The secret of this in- 
 strument is to keep the pupil of the eye exactly upon the 
 edge of the prism, so that the one half of the pupil looks 
 at the object, and the other half at the paper and pencil. 
 
 The great value of the camera lucida lies in the 
 fact that a perfectly accurate sketch of any object 
 can be taken by one who knows nothing whatever of 
 drawing, the process being much the same as that of 
 drawing on a transparent slate. The saving of time is 
 very great, as a sketch can be made with a rapidity 
 
STEEL MIRROR AND NEUTRAL GLASS. 53 
 
 that seems almost marvellous to a bystander, and the 
 drawing is sure to be in perfect proportion. The reader 
 will see by the diagram of the rays that the size of the 
 drawing will be precisely according to the distance of 
 the camera from the paper, so that if he wishes to 
 make a small sketch, he places the paper close to the 
 prism, and if he desires a large drawing, removes it to 
 some distance. Indeed, a very large diagram, suitable 
 for the walls of a lecture-room, can be made by laying 
 the paper on the floor, and drawing with a pencil fixed 
 in a very long handle. Minute details of colour, &c. 
 are added after the outline sketch is completed. 
 
 There are several modes of attaining the same end, 
 among which the steel mirror and the neutral glass are 
 the best. The former is a very tiny circular plate of steel, 
 placed in the same position as the edge of the camera 
 lucida, and turned at such an angle that the eye looks 
 in the mirror at the object, and around it at the paper. 
 The cheapest instrument for this purpose is the neutral 
 glass plate, invented by Dr. L. Beale, and which will 
 be found to perform admirably the functions of the 
 camera lucida, without costing more than one-fourth of 
 the price. 
 
 By means of a little ingenuity, the camera can be 
 mounted on the stand of the dissecting microscope, 
 and can be thus employed for sketching solid objects 
 
64 MICROSCOPIC FORMULA. 
 
 or copying drawings. By a neat adjustment of the 
 height of the instrument the camera lucida will always 
 produce a sketch exactly to scale, and will give a 
 drawing of twenty, thirty, or a hundred diameters at 
 will. It will therefore be seen that the draughtsman 
 must be very careful to have the instrument placed at 
 an established series of heights above the paper, and he 
 should always append to each sketch the magnifying 
 power with which it was drawn. Thus 
 
 "Epidermis and stomata of Holly-berry, ^ X 150." 
 
 By which formula will be understood that the object- 
 glass employed is that called the " four- tenths " glass, 
 and that the object is magnified one hundred and fifty 
 diameters. Unless this precaution be taken, great 
 confusion in respect to the size of the object is sure to 
 arise. 
 
 To return to our former subject. 
 
 On the opposite bottom corner of Plate I., fig. 2o is 
 an example of a stoma taken from the outer skin of a 
 Gourd, and here given for the purpose of observing the 
 curious manner in which the cells are arranged about 
 the mouth, no less than seven cells being placed round 
 the single mouth, and the others arranged in a partially 
 circular form around them. 
 
 Turning to Plate II. we find several other examples 
 of stomata, the first of which, fig. 1, is obtained from 
 
WAVED CELLS OP LEAF. 55 
 
 the under surface of the Buttercup leaf, by stripping off 
 the external skin, or " epidermis," as it is scientifically 
 termed. The reader will here notice the slightly waved 
 outlines of the cell-walls, together with the abundant 
 spots of chlorophyll with which the leaf is coloured. 
 In this example, the stomata appear open. The 
 closure or expanding of the mouth depends most on 
 the- state of the weather, and, as a general rule, they 
 axe open by day and closed at night. Some plants are 
 provided with four guarding cells, which are arranged 
 in different manners. 
 
 A remarkably pretty example of stomata and elon- 
 gated cells is to be obtained from the leaf of the common 
 Iris, and may be prepared for the microscope by simply 
 tearing off a strip of the cuticle from the under side of 
 the leaf, laying it on a slide, putting a little water on 
 it, and covering it with a piece of thin glass. (See 
 Plate II. fig. 2.) The peculiar elongated cells will not 
 be seen equally spread over the whole surface of the 
 leaf, as they are hidden by a congeries of shorter and 
 thicker cells, covered with chlorophyll which conceals 
 their shape. There are, however, a number of longitu- 
 dinal bands running ajong the leaf, where these cells and 
 mouths appear, without anything to veil their beauty. 
 The stomata are not placed at regular intervals, for it j 
 often happens that the whole field of the microscope will 
 
56 SPIRAL AND RINGED VESSELS. 
 
 be filled with cells without a single stoma, while a 
 group of three or four are often seen clustered closely 
 together. 
 
 Fig. 3 on the same plate exhibits a specimen of 
 beautifully waved cells, without mouths, which are 
 found on the upper surface of the Ivy leaf. These are 
 difficult to arrange from the fresh leaf, but are easily 
 shown by steeping the leaf in water for some time, and 
 then tearing away the cuticle. The same process may 
 be adopted with many leaves and cuticles, and in some 
 cases the immersion must be continued for many days, 
 and the process of decomposition aided by a very little 
 nitric acid in the water, or by boiling. 
 
 On the same plate are three examples of spiral and 
 ringed vessels, being types of an endless variety of 
 these beautiful and interesting structures. Fig. 4 is 
 a specimen of a spiral vessel taken from the Lily, and 
 is a beautiful example of a double spire. The deposit 
 which forms this spiral is very strong, and it is to the 
 vast number of these vessels that the stalk owes its 
 well-known elasticity. In many cases the spiral vessels 
 are sufficiently strong to be visible to the naked eye, 
 and ? to bear uncoiling. For example, if a leaf-stalk of 
 geranium be broken across, and the two fragments 
 gently drawn asunder, a great number of spiral vessels 
 will be seen connecting the broken ends. In this case 
 
ANALOGIES OF NATURE. 57 
 
 the delicate membranous walls of the vessel are torn 
 apart, and the stronger fibre which is coiled spirally 
 within them unrolls itself in proportion to the force 
 employed. In many cases these coils are so strong that 
 they will sustain the weight of an inch or so of the 
 stalk. 
 
 In fig. 5 is seen a still more bold and complex form 
 of this curious structure ; being a coil of five threads 
 laid closely against each other, and forming while 
 remaining in their natural position an almost continuous 
 tube. This specimen is taken from the root of the 
 Water Lily, and requires some little care to exhibit its 
 structure properly. 
 
 Every student of nature must be greatly struck with 
 the analogies between different portions of the visible 
 creation. These spiral structures which we have just 
 examined are almost identical in appearance, and 
 entirely so in functions, with the threads that are 
 coiled within the breathing tubes of insects. Their 
 object in both cases is twofold, namely to give strength 
 and elasticity to a delicate membrane, and to preserve 
 the tube in its proper form despite the flexure to which 
 it may be subjected. When we come to the anatomy 
 of the insect in a future page, we shall see this structure 
 further exemplified. 
 
 In some cases the deposit, instead of forming a 
 
58 HAIRS OP PLANTS. 
 
 spiral coil, is arranged in a series of rings, and is then 
 termed " annulated." A very good example of this 
 formation is given in fig. 6, being a sketch of a ringed 
 vessel, taken from a stalk of the common Rhubarb. To 
 see these ringed vessels properly, the simplest plan is to 
 boil the rhubarb until it is quite soft, then to break 
 down the pulpy mass until it is flattened, to take some 
 of the most promising portions with the forceps, lay 
 them on the slide and press them down with a thin 
 glass cover. They will not be found scattered at 
 random through the fibres, which elsewhere present 
 only a congeries of elongated cells, but are seen grouped 
 together in bundles, and with a little trouble may 
 be well isolated, and the pulpy mass worked away so as 
 to show them in their full beauty. As may be seen in 
 the illustration, the number of the rings and their 
 arrangement is extremely variable. 
 
 The Hairs of plants always form very interesting 
 objects, and are instructive to the student, as they 
 afford valuable indications of the mode in which plants 
 grow. They are all appendages of and arising from 
 the skin or epidermis ; and although their simplest form 
 is that of a projecting and elongated cell, the variety 
 of shapes which are assumed by these organs is 
 inexhaustible. On Plate II. are examples of some 
 
FORKED AND BEADED HAIRS. 59 
 
 of the more striking forms, which will be briefly 
 described. 
 
 The simple hair is well shown in figs. 18, 19, and 
 32, the first being from the flower of the Heartsease, 
 the second from a Dock-leaf, and the third from a 
 Cabbage. In fig. 18 the hair is seen to be but a single 
 projecting cell, consisting only of a wall and the 
 contents. In fig. 19 the hair has become more decided 
 in shape, having assumed a somewhat dome-like form, 
 and in fig. 32 it has become considerably elongated, and 
 may at once be recognised as a true hair. 
 
 In fig. 8 is a curious example of a hair taken from 
 the white Arabis, one of the cruciform flowers, which is 
 remarkable for the manner in which it divides into two 
 branches, each spreading in opposite directions. Another 
 example of a forked hair is seen in fig. 13, but in this 
 instance the hair is composed of a chain of cells, the 
 three lower forming the stem of the hair, and the two 
 upper being lengthened into the lateral branches. This 
 hair is taken from the common Southernwood. 
 
 In most cases of long hairs, the peculiar elongation 
 is formed by a chain of cells, varying greatly in length 
 and development. Several examples of these hairs will 
 be seen on the same plate. 
 
 Fig. 9 is a beaded hair from the Marvel of Peru, 
 which is composed of a number of separate cells placed 
 
60 LASHED HAIRS. 
 
 end to end, and connected by slender threads in a 
 manner that strongly reminds the observer of a chain 
 of beads strung loosely together, so as to show the 
 thread by which they are connected with each other. 
 Another good example is seen at fig. 11, in a hair taken 
 from the leaf of the Sow-thistle. In this case the beads 
 are strung closely together, and when placed under a 
 rather high power of the microscope, have a beautifully 
 white and pearly aspect. The leaf must be dry and 
 quite fresh, and the hairs seen against the green of the 
 leaf. Fig. 39 represents another beaded hair taken 
 from the Virginian Spiderwort, or Tradescantia. This 
 hair is found upon the stamens, and is remarkable for 
 the beautifully beaded outline, the fine colouring, and 
 the spiral markings with which each cell is adorned. 
 
 A still further modification of these many-celled 
 hairs is found in several plants, where the hairs are 
 formed by a row of ordinarily shaped cells, with the 
 exception of the topmost cell, which is suddenly elon- 
 gated into a whip-like form. Fig. 22 represents a hair 
 of this kind, taken from the common Groundsel; and 
 fig. 36 is a still more curious instance, found upon the 
 leaf of the Thistle. The reader may have noticed the 
 peculiar white "fluffy" appearance of the thistle leaf 
 when it is wet after a shower of rain. This appearance 
 is produced by the long lash-like ends of the hairs, 
 
STING OF NETTLE. 61 
 
 which are bent down by the weight of the moisture, 
 and lie almost at right angles with the thicker portions 
 of the hair. 
 
 An interesting form of hair is seen in the "sting" of 
 the common Nettle. This may readily be examined by 
 holding a leaf edgeways in the stage forceps, and laying 
 it under the field of the microscope. In order to get 
 the proper focus throughout the hair, the finger should 
 be kept upon the screw movement, and the hair brought 
 gradually into focus from its top to its base. The general 
 idea of this hair is not unlike that which characterises 
 the sting of the bee or wasp. The acrid fluid which 
 causes the pain is situated in the enlarged base of the 
 hair, and is forced through the long straight tubular 
 extremity by means of the pressure exerted when the 
 sting enters the skin. At the very extremity of the 
 perfect sting is a slight bulb-like swelling, which serves 
 to confine the acrid juice, and which is broken off on 
 the least pressure. The sting is seen in fig. 43. The 
 extremities of many hairs present very curious forms, 
 some being long and slender, as in the examples already 
 mentioned, while others are tipped with knobs, bulbs, 
 clubs, or rosettes in endless variety. 
 
 Fig. 12 is a hair of the Tobacco leaf, exhibiting the 
 two-celled gland at the tip, containing the peculiar 
 principle of the plant, which goes scientifically by the 
 
62 BRANCHED HAIRS. 
 
 name of " nicotine." The reader will see how easy it 
 is to detect adulteration of tobacco by means of the 
 microscope. The leaves most generally used for this 
 purpose are the Dock and the Cabbage, 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 substitute. 
 
 Fig. 15 is a hair from the flower of the common 
 yellow Snapdragon, which is remarkable for the peculiar 
 shape of the enlarged extremity, and for the spiral mark- 
 ings with which it is decorated. Fig. 16 is a curious 
 little knobbed hair found upon the Moneywort, and fig. 
 17 is an example of a double-knobbed hair, taken from 
 the Geum. Fig. 34 affords a very curious instance of 
 a glandular hair, the stem being built up of cells dis- 
 posed in a very peculiar fashion, and the extremity 
 being developed into a beautiful rosette-shaped head. 
 This hair came from the garden Verbena. 
 
 Curiously branched hairs are not at all uncommon, 
 and some very good and easily obtained examples are 
 given on Plate II. 
 
 Fig. 28 is one of the multitude of branched hairs 
 that surround the well-known fruit of the Plane-tree, 
 the branches being formed by some of the cells point- 
 ing outward. These hairs do not assume precisely the 
 same shape, for fig. 30 exhibits another hair from the 
 
PERFUME CELLS. 63 
 
 same locality, on which the spikes are differently 
 arranged, and fig. 29 is a sketch of another such hair, 
 where the branches have become so numerous and so 
 well developed that they are quite as conspicuous as 
 the parent stem. 
 
 One of the most curious and interesting forms of 
 hair is that which is found upon the Lavender leaf, 
 and which gives it the peculiar bloom-like appear- 
 ance on the surface. 
 
 This hair is represented in figs. 40 and 41. On fig. 
 40 the hair is shown as it appears when looking directly 
 upon the leaf, and in fig. 41 a section of the leaf is 
 given, showing the mode in which the hairs grow into 
 an upright stem, and then throw out horizontal branches 
 in every direction. Between the two upright hairs, and 
 sheltered under their branches, may be seen a glandular 
 appendage, not unlike that which is shown in fig. 16. 
 This is the reservoir containing the perfume, and it 
 is evidently placed under the spreading branches for 
 the benefit of their shelter. On looking upon the leaf 
 by reflected light, the hairs are beautifully shown, 
 extending their arms on all sides; and the globular 
 perfume-cells may be seen scattered plentifully about; 
 gleaming like pearls through the hair branches under 
 which they repose. They will be found more numerous 
 on the under-side of the leaf. 
 
64 RESINS, SCENTS, AND OILS. 
 
 This object will serve to answer a question which the 
 reader has probably put to himself ere this, namely, 
 Where are the fragrant resins, scents, and oils stored ? 
 On Plate I. fig. 16, will be seen the reply to the first 
 question, fig. 41 of the present plate has answered the 
 second question, and fig. 42 will answer the third. 
 This figure represents a section of the rind of an 
 Orange, the flattened cells above constituting the delicate 
 yellow skin, and the great spherical object in the centre 
 being the reservoir in which the fragrant essential oil 
 is stored. The covering is so delicate that it is easily 
 broken, so that even by handling an orange some of 
 the scent is sure to come off on the hands, and when 
 the peel is stripped off and bent double, the reservoirs 
 burst in myriads, and fling their contents to a won- 
 derful distance. This may be easily seen by squeezing 
 a piece of orange peel opposite a lighted candle, and 
 noting the distance over which the oil will pass before 
 reaching the flame, and bursting into little flashes of 
 light. Other examples are given on the same Plate. 
 
 Returning to the barbed hairs, we may see in fig. 35 
 a highly magnified view of the "pappus" hair of a 
 Dandelion, i.e. the hairs which fringe the arms of the 
 parachute-like appendage which is attached to the seed. 
 The whole apparatus will be seen more fully on Plate 
 III. figs. 44, 45, 46. This hair is composed of a 
 
KNOBBED HAIRS. 65 
 
 double layer of elongated cells lying closely against 
 each other, and having the ends of each cell jutting 
 out from the original line. A simpler form of a 
 double-celled, or more properly a " duplex " hair, will 
 be seen in fig. 44. This is one of the hairs from the 
 flower of the Marigold, and has none of the projecting 
 ends to the cells. 
 
 In some instances the cell-walls of the hairs become 
 exceedingly hardened by secondary deposit, and the 
 hairs are then better known by the name of spines. 
 Two examples of these strengthened hairs are seen in 
 figs. 37 and 38, the former being picked from the Indian 
 Fig-cactus, and well known to those persons who have 
 been foolish enough to handle the fig roughly before 
 feeling it. The wounds which these spines will inflict 
 are said to be very painful, and have been compared to 
 those produced by the sting of the wasp. The latter 
 hair is taken from the Opuntia. 
 
 The mode in which hairs increase in length is well 
 shown in fig. 10, which represents the extreme tip of a 
 hair from the Hollyhock leaf, subjected to a lens of 
 very high power. 
 
 Many hairs assume a star-like appearance, an aspect 
 
 which may be produced in different ways. Sometimes 
 
 a number of simple hairs start from the same base, 
 
 and by radiating in different directions produce the 
 
 p 
 
66 HAIR FROM PANSY. 
 
 stellate effect. An example of this kind of hair may 
 be seen in fig. 14, which is a group of hairs from the 
 Hollyhock leaf. There is another mode of producing 
 the star-shape, which may be seen in fig. 4o, a hair 
 taken from the leaf of the Ivy. 
 
 Several hairs are covered with curious little branches 
 or protuberances, and present many other peculiarities 
 of form, which throw a considerable light upon certain 
 problems in scientific microscopy. 
 
 Fig. 33 represents a hair of two cells taken from the 
 flower of the well-known Dead-nettle, which is remark- 
 able for the number of knobs scattered over its surface. 
 A similar mode of marking is seen in fig. 31, a club- 
 shaped hair covered with external projections, found in 
 the flower of the Lobelia. In order to exhibit these 
 markings well, a power of two hundred diameters is 
 needed. Fig. 21 shows this dotting in another hair 
 from the Dead-nettle, where the cell is drawn out to 
 a great length, but is still covered with these markings. 
 
 Fig. 20 is an example of a very curious hair taken 
 from the throat of the Pansy. This hair may readily 
 be obtained by pulling out one of the petals, when the 
 hairs will be seen at its base. Under the microscope it 
 has a particularly beautiful appearance, looking just 
 like a glass walking-stick covered with knobs, not 
 unlike those huge, knobby, club-like sticks in which 
 
BARK CELLS. 67 
 
 some farmers delight, where the projections have been 
 formed by the pressure of a honeysuckle or other 
 climbing plant. 
 
 A hair of a similar character, but even more curious 
 is found in the same part of the flower of the garden 
 Verbena (see fig. 27), and is not only beautifully trans- 
 lucent, but is coloured according to the tint of the 
 flower from which it is taken. Its whole length is 
 covered with large projections, the joints much resem- 
 bling antennae belonging to certain insects, and each 
 projection is profusely spotted with little dots, formed 
 by elevation of the outer skin or cuticle. These are of 
 some value in determining the structure of certain ap- 
 pearances upon petals and other portions of flowers, and 
 may be compared with figs. 33 to 35 on Plate III. 
 
 Fig. 26 offers an example of the squared cells which 
 usually form the bark of trees. This is a transverse 
 section of Cork, and perfectly exhibits the form of 
 bark cells. The reader is very strongly advised to 
 cut a delicate section of the bark of various trees, a 
 matter very easily accomplished with the aid of a 
 sharp razor and a steady hand. 
 
 Fig. 24 is a transverse section through one of the 
 scales of a Pine-cone, and is here given for the purpose 
 of showing the numerous resin-filled cells which it 
 displays. This may be compared with fig. 16 of Plate I, 
 
68 OBJECT OF THE WORK. 
 
 Fig. 25 is a part of one of the " vittae," or oil reservoirs 
 from the fruit of the Caraway, showing the cells con- 
 taining the globules of caraway oil. This is rather a 
 curious object, because the specimen from which it 
 was taken was boiled in nitric acid, and yet retained 
 some of the oil globules. Immediately above it may 
 be seen (fig. 23) a transverse section of the Beechnut, 
 showing a cell with its layers of secondary deposit. 
 These are but short and meagre accounts of a very few 
 objects, but space will not permit of further elucidation, 
 and the purpose of this little work is not to exhaust 
 the subjects of which it treats, but to incite the reader 
 to investigation on his own account, and to make his 
 task easier than if he had undertaken it unaided. 
 
 In the cuticles of the Grasses and the Mare's-tails is 
 deposited a large amount of pure flint. So plentiful 
 is this substance, and so equally is it distributed, that 
 it can be separated by heat or acids from the vegetable 
 parts of the plant, and will still preserve the form of 
 the original cuticle, with its cell-walls, stomata, and 
 hairs perfectly well denned. 
 
 Fig. 7, Plate II., represents a piece of wheat chaff or 
 ft bran," that has been kept at a white heat for some 
 time, and then mounted in Canada balsam. I prepared 
 the specimen from which the drawing was made by 
 laying the jcbaff on a piece of platinum, and holding it 
 
SILEX OR FLINT. 69 
 
 over the spirit-lamp. A good example of the silex or 
 flint in wheat is often given by the remains ot a straw 
 fire, where the stems may be seen still retaining their 
 tubular form, but fused together into a hard glassy 
 mass. It is this substance that cuts the fingers of 
 those who handle the wild grasses too roughly, the 
 edges of the blades being serrated with flinty teeth, 
 just like the obsidian swords of the ancient Mexicans, 
 or the shark's-tooth falchion of the New Zealander. 
 
70 
 
 CHAPTER IV. 
 
 STARCH, ITS GROWTH AND PROPERTIES SURFACE CELLS OP 
 PETALS POLLEN AND ITS FUNCTIONS SEEDS MOUNTING 
 OBJECTS IN CANADA BALSAM MOUNTING OBJECTS DRY AND IN 
 CELLS HOW TO MAKE CELLS TURN-TABLE PRESERVATIVE 
 FLUIDS. 
 
 THE white substance so dear to the laundress under 
 the name of Starch is found in a vast variety of plants, 
 being distributed more widely than most of the pro- 
 ducts which are found in the interior of vegetable 
 cells. 
 
 The starch grains are of very variable size even in 
 the same plant, and their form is as variable as their 
 size. Sometimes the grains are found loosely packed 
 in the interior of the cells, and are then easily recog- 
 nised by their peculiar form and the delicate lines 
 with which they are marked ; but in many places they 
 are pressed so closely together, that they assume an 
 hexagonal shape under the microscope, and bear a close 
 resemblance to ordinary twelve-sided cells. In other 
 plants again, the grains never advance beyond the very 
 
GROWTH OP STARCH. 71 
 
 minute form in which they seem to commence their 
 existence; and in some, such as the common Oat, a 
 great number of very little granules are compacted 
 together so as to resemble one large grain. 
 
 There are several methods of detecting starch in 
 those cases where its presence is doubtful ; and the two 
 modes that are usually employed are polarized light 
 and the iodide of potassium. When polarized light is 
 employed a subject on which we shall have something 
 to say presently the starch grains assume the charac- 
 teristic " black-cross," and when a plate of selenite is 
 placed immediately beneath the slide containing the 
 starch grains, they glow with all the colours of the 
 rainbow. The second plan is to treat them with a 
 very weak solution of iodide of potassium, and in this 
 case the iodine has the effect on the starch granules 
 of staining them blue. They are so susceptible of this 
 colour, that when the liquid is too strong, the grains 
 actually become black from the amount of iodine 
 which they imbibe. 
 
 Nothing is easier than to procure the starch granules 
 in the highest excellence. Take a raw Potato, and with 
 a razor cut a very thin slice from its interior, the direc- 
 tion of the cut not being of the slightest importance. 
 Put this delicate slice upon a slide, drop a little water 
 upon it, cover it with a piece of thin glass, give it a 
 
72 GROWTH OF STARCH, 
 
 good squeeze, and place it under a power of a hun- 
 dred or a hundred and fifty diameters. Any part of 
 the slice, provided that it be very thin, will then present 
 the appearance shown in Plate III. fig. 9, where an 
 ordinary cell of potato is seen filled loosely with starch- 
 grains of different sizes. Around the edges of the slice 
 a vast number of starch granules will be seen, which 
 have been squeezed out of their cells by pressure, and 
 which are now floating freely in the water. As cold 
 water has no perceptible effect upon starch, the grains 
 are not altered in form by the moisture, and can be 
 examined at leisure. 
 
 On focussing with great care, the surface of each 
 granule will be seen to be covered with very minute 
 dark lines, arranged in a manner which can be readily 
 comprehended from fig. 4, which represents two granules 
 of potato-starch, as they appear when removed from 
 the cell in which they took their origin. All the lines 
 evidently refer to the little dark spots at the end of 
 the granule, called technically the " hilum." 
 
 The mode by which the starch granules increase in 
 size has long been a problem to microscopists, and 
 seems likely to remain so for the present, one party 
 asserting that the outermost layers are the youngest, 
 and others that they are the oldest. All, however, are 
 agreed upon the one point, that the delicate lines are 
 
STARCH WHEN COOKED. 73 
 
 the boundaries of successive layers of the substance of 
 which the granule is composed. 
 
 In the earliest stages of their growth, the starch 
 granules appear to be destitute of these markings, or 
 at all events they are so few and so delicate as not to 
 be visible even with the most perfect instruments, and 
 it is not until they assume a comparatively large size 
 that the external markings become distinctly per- 
 ceptible. 
 
 We will now glance at the examples of starch which 
 are given in the plate, and which are a very few out 
 of the many that might be figured. 
 
 Fig. 2 represents the starch of Wheat, the upper 
 grain being seen in front, the one immediately below it 
 being in profile, and the two others being examples of 
 smaller grains. Fig. 6 is a specimen of a very minute 
 form of starch, where the granules do not seem to 
 advance beyond their earliest stage. This specimen is 
 obtained from the Parsnip; and although the magnify- 
 ing power is very great, their dimensions are exceed- 
 ingly small, and, except to a very practised .eye, they 
 could not be recognisable as starch grains. 
 
 Fig. 3 is a good example of a starch-grain of Wheat, 
 exemplifying the change that takes place by the effects 
 of combined heat and moisture. It has already been 
 observed that cold water exercises little, if any, per- 
 
74 COMPOUND GRANULES. 
 
 ceptible influence upon the starch; but it will be seen 
 from the illustration, that hot water has a very powerful 
 effect. When subjected to this treatment, the granule 
 swells rapidly, and at last bursts, the contents escaping 
 in a flocculent cloud, and the external membrane col- 
 lapsing into the form which is shown in fig. 3, which 
 was taken out of a piece of hot pudding. A similar 
 form of wheat starch may also be detected in bread, 
 and accompanied unfortunately by several other sub- 
 stances not generally presumed to be component parts 
 of the "staff of life." 
 
 In fig. 7 are represented some grains of starch from 
 West Indian Arrowroot, and fig. 8 exhibits the largest 
 kind of starch-grain known, obtained from the tuber 
 of a species of Canna, supposed to be C. edulis, a plant 
 similar in characteristics to the arrowroot. The popu- 
 lar name of this starch is " Tous les Mois," and under 
 that title it may be obtained from the opticians. 
 
 Fig. 10 shows the starch-granules from Indian Corn, 
 as they appear before they are compressed into the 
 honeycomb-like structure which has already been men- 
 tioned. Even in that state, however, if they are treated 
 with iodine, they exhibit the characteristics of starch in 
 a very perfect manner. Fig. 11 is starch from Sago, 
 and fig. 12 from Tapioca, and in both these instances 
 the several grains have been injured by the heat 
 
LEAP VARNISH. 75 
 
 employed in preparing the respective substances for 
 the market. 
 
 Fig. 13 exhibits the granules obtained from the root 
 of the Water-Lily, and fig. 14 is a good example of the 
 manner in which the starch-granules of Eice are pressed 
 together so as to alter the shape and puzzle a novice. 
 Fig. 16 is the compound granule of the Oat, which has 
 already been mentioned, together with some of the 
 simple granules separated from the mass ; and fig. 15 
 is an example of the starch-grains obtained from the 
 underground stem of the Horse-bean. 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 touch. 
 
 IN Plate III. fig. 1, may be seen a curious little 
 drawing, which is a sketch of the Laurel-leaf cut 
 transversely, and showing the entire thickness of the 
 leaf. Along the top may be seen the delicate layer of 
 " varnish " with which the surface of the leaf is covered, 
 and which serves to give to the foliage its^ peculiar 
 polish. This varnish is nothing more than the trans- 
 lucent matter which binds all the cells together, and 
 which is poured out very liberally upon the surface of 
 the leaf. The lower part of this section exhibits the 
 cells of which the leaf is built, and towards the left 
 
76 SURFACE CELLS OF PETALS. 
 
 hand may be seen a cut end of one of the veins of the 
 leaf, more rightly called a wood-cell. 
 
 We will now examine a few examples of surface cells. 
 
 Fig. 5 is a portion of epidermis stripped from a 
 Capsicum pod, exhibiting the remains of the nuclei 
 in the centre of each cell, together with the great 
 thickening oi the wall-cells and the numerous pores 
 for the transmission of fluid. This is a very pretty 
 specimen for the microscope, as it retains its bright red 
 colour, and even in old and dried pods exhibits the 
 characteristic markings. 
 
 In the centre of the plate may be seen a wheel-like 
 arrangement of the peculiar cells found on the petals of 
 six different flowers, all easily obtainable, and mounted 
 without difficulty. 
 
 Fig. 30 is the petal of a Geranium (Pelargonium), a 
 very common object on purchased slides. It is a most 
 lovely subject for the microscope, whether it be exa- 
 mined with a low or a high power, in the former 
 instance exhibiting a most beautiful " stippling " of 
 pink, wlyte, and black, and in the latter showing the 
 six-sided cells with their curious markings. 
 
 In the centre of each cell is seen a radiating arrange- 
 ment of dark lines with a light spot in the middle, 
 looking very like the mountains on a map. These 
 lines tvere long thought to be hairs j but Mr. Tufien 
 
PETAL OF PERIWINKLE. 77 
 
 West, in an interesting and elaborate paper on the 
 subject, has shown their true nature. From his ob- 
 servations it seems that the beautiful velvety aspect 
 of flower petals is owing to these arrangements of the 
 surface cells, and that their rich brilliancy of colour is 
 due to the same cause. The centre of each cell-wall 
 is elevated as if pushed up by a pointed instrument 
 from the under side of the wall, and in different flowers 
 this elevation assumes different forms. Sometimes it 
 is merely a slight wart on the surface, sometimes it 
 becomes a dome, while in other instances it is so 
 developed as to resemble a hair. Indeed, Mr. West 
 has concluded that these elevations are nothing more 
 than rudimentary hairs. 
 
 The dark radiating lines are shown by the same 
 authority to be formed by wrinkling of the membrane 
 forming the walls of the elevated centre, and not to 
 be composed of " secondary deposit," as has generally 
 been supposed. 
 
 Fig. 31 represents the petal of the common Peri- 
 winkle, differing from that of the geranium by the 
 straight sides of the oell-walls, which do not present 
 the toothed appearance so conspicuous in the former 
 flower. A number of little tooth-like projections may 
 be seen on the interior of the cells, their bars affixed 
 to the walls and their points tending towards the 
 
78 FRESH PETALS NEEDFUL. 
 
 centre, and these teeth are, according to Mr. West, 
 formed of secondary deposit. 
 
 In fig. 32 the petal of the common garden Balsam 
 is shown, where the cells are observed to be elegantly 
 waved on their outlines, and with plain walls. The 
 petal of the Primrose is seen in fig. 34, and that of 
 the yellow Snapdragon in fig. 33, in which latter 
 instance. the surface cells assume a most remarkable 
 shape, running out into a variety of zigzag outlines 
 that quite bewilder the eye when the object is first 
 placed under the microscope. Fig. 35 is the petal of 
 the common Scarlet Geranium. 
 
 In several instances these petals are too thick to be 
 examined without some preparation, and glycerine will 
 be found well adapted for that purpose. The young 
 microscopist must, however, beware of forming his ideas 
 upon preparations of dried leaves, petals, or hairs, and 
 should always procure them in their fresh state when- 
 ever he desires to make out their structure. Even a 
 fading petal should not be used, and if the flowers 
 are gathered for the occasion, their stalks should be 
 placed in water, so as to give a series of leaves and 
 petals as fresh as possible. 
 
 WE now pass from the petal of the flower to the 
 Pollen, that coloured dust, generally yellow or white, 
 
POLLEN. 79 
 
 which is found upon the stamens, and which is very 
 plentiful in many flowers, such as the Lily and the 
 Hollyhock. 
 
 This substance is found only upon the stamens or 
 anthers of full-blown flowers which represent the 
 male sex, and is intended for the purpose of enabling 
 the female portion of the flower to produce fertile 
 seeds. In form the pollen grains are wonderfully 
 diverse, affording an endless variety of beautiful shapes. 
 In some cases the exterior is smooth and only marked 
 with minute dots, but in many instances the outer 
 wall of the pollen grain is covered with spikes or 
 decorated with stripes or belts. A few examples of 
 the commonest forms of pollen will be found on 
 Plate III. 
 
 Fig. 17 is the pollen of the Snowdrop, and, as will 
 be seen, is covered with dots and marked with a 
 definite slit along its length. The dots are simply 
 tubercles in the outer coat of the grain, and are pre- 
 sumed to be formed for the purpose of strengthening the 
 otherwise too delicate membrane, after the same prin- 
 ciple that gives to " corrugated " iron such strength in 
 proportion to the amount of material. Fig. 18 is the 
 pollen of the Wall-flower, shown in two views, and 
 having many of the same characteristics as that of the 
 snowdrop. Fig. 19 is the pollen of the Willow-herb, 
 
80 POLLEN-TUBES AND THEIR FUNCTION. 
 
 and is here given as an illustration ot the manner 
 in which the pollen aids in the germination of plants. 
 
 In order to understand its action, we must first 
 examine its structure. 
 
 All pollen-grains are furnished with some means by 
 which their contents when thoroughly ripened can be 
 expelled. In some cases this end is accomplished by 
 sundry little holes called pores ; in others, certain tiny 
 lids are pushed up by the contained matter ; and in 
 some, as in the present instance, the walls are thinned 
 in certain places so as to yield to the internal pressure. 
 
 When a ripe pollen-grain falls upon the stigma or 
 a nectary of a flower, it immediately begins to swell, 
 and seems to "sprout" like a potato in a damp cellar, 
 sending out a slender "pollen-tube" from one or other of 
 the apertures already mentioned. In fig. 19, a pollen- 
 tube is seen issuing from one of the projections, and illus- 
 trates the process better than can be achieved by mere 
 verbal description. The pollen- tubes then insinuate 
 themselves among the cells of the stigmas, and con- 
 tinually elongating, worm their way down the " style " 
 until they come in contact with the " ovules." By 
 very careful dissection of a fertilizing stigma, the 
 beautiful sight of the pollen-tubes winding along the 
 tissues of the style may be seen under a high power of 
 the microscope. 
 
CONTENTS OF POLLEN. 81 
 
 The pollen-tube is nothing more than the interior 
 coat of the grain, very much developed, and filled with 
 a substance technically named " fovilla," composed of 
 a " protoplasm," or that liquid substance which is found 
 in the interior of cells, very minute starch-grains, and 
 some apparently oily globules. 
 
 In order to examine the structure of the pollen- 
 grains properly, they should be examined under various 
 circumstances some dry, others placed in water to 
 which a little sugar has been added, others in oil, and 
 it will often be found useful to try the effect of dif- 
 ferent acids upon them. 
 
 Fig. 20 is the pollen of the common Violet, and 
 is easily recognisable by its peculiar shape and 
 markings. Fig. 21 is the pollen of the Musk-plant, 
 and is notable for the curious mode in which its 
 surface is belted with wide and deep bands, running 
 spirally round the circumference. Fig. 22 exhibits the 
 pollen of the Apple, and fig. 23 affords a very curious 
 example of the raised markings upon the surface of 
 Dandelion pollen. In fig. 24 there are also some 
 very wonderful markings, but they are disposed after 
 a different fashion, forming a sort of network upon 
 the surface, and leaving several large free spaces 
 between the meshes. The pollen of the Lily is shown 
 in fig. 25, and is a good example of a pollen-grain 
 
 a 
 
82 GROWTH OF POLLEN. 
 
 covered with the minute dottings which have already 
 been described. 
 
 Figs. 26 and 27 show two varieties of compound 
 pollen, found in two species of Heath. These com- 
 pound pollen-grains are not of unfrequent occurrence, 
 and are accounted for in the following manner. 
 
 The pollen is formed in certain cavities within the 
 anthers, by means of the continual subdivision of the 
 "parent-cells" in which it is developed. In many 
 cases the form of the grain is clearly owing to the 
 direction in which these cells are divided, but there is 
 no great certainty on this subject. It will be seen, 
 therefore, that if the process of subdivision be suddenly 
 arrested, the grains will be found adhering to each 
 other in groups of greater or smaller size, according to 
 the character of the species and the amount of sub- 
 division that has taken place. The reader must, how- 
 ever, bear in mind that the whole subject is as yet rather 
 obscure, and that further discovery may throw a dif- 
 ferent light on many theories which at present are 
 accepted as established rules. 
 
 Fig. 28 shows the pollen of the Furze, in which are 
 seen the longitudinal slits and the numerous dots on 
 the surface ; and fig. 29 is the curiously shaped pollen 
 of the Tulip. The two large yellow globular figures at 
 each side of the plate represent the pollen of two 
 
SEEDS OF PLANTS. 83 
 
 common flowers ; fig. 36 being that of the Crocus, and 
 fig. 37 a pollen-grain of the Hollyhock. As may be 
 seen from the illustration, the latter is of considerable 
 size, and is covered with very numerous projections. 
 These serve to raise the grain from a level surface, over 
 which it rolls with a surprising ease of motion, so 
 much so indeed that if a little of this substance be 
 placed on a slide and a piece of thin glass laid over it, 
 the glass slips off as soon as it is in the least inclined, 
 and forces the observer to fix it with paper or cement 
 before he can place it on the inclined stage of the 
 microscope. The little projections have a very curious 
 effect under a high power, and require careful focussing 
 to observe them properly ; for the diameter of the 
 grain is so large, that the focus must be altered to 
 suit each individual projection. Their office is, pro- 
 bably, to aid in fertilizing. 
 
 THE Seeds of plants are easier of examination even 
 than the pollen, and in most cases require nothing but 
 a pocket lens and a needle for making out their general 
 structure. The smaller seeds, however, must be placed 
 under the microscope, many of them exhibiting very 
 curious forms. The external coat of seeds is often of 
 great interest, and needs to be dissected off before it 
 can be rightly examined. The simplest plan in such a 
 G 2 
 
84 PLUMED SEEDS. 
 
 case is to boil the seed well, press it while still warm into 
 a plate of wax, and then dissect with a pair of needles, 
 forceps, and scissors under water. A few examples of 
 the seeds of common plants are given at the bottom of 
 Plate III. 
 
 Fig. 38 exhibits the fruit, popularly called the seed, 
 of the common Goosegrass, or Galium, which is remark- 
 able for the array of booklets with which it is covered. 
 Immediately above the figure may be seen a drawing of 
 one of the hooks much magnified, showing its sharp 
 curve, fig. 39. It is worthy of remark that the hook 
 is not a simple curved hair, but a structure composed 
 of a number of cells terminating in a hook. 
 
 Fig. 40 is the seed, or rather the fruit, of the common 
 red Valerian, and is introduced for the purpose of 
 showing the plumed extremity, which acts as a parachute 
 and causes it to be carried about by the wind until it 
 meets with a proper re? ting-place. It is also notable 
 for the series of strong longitudinal ribs which support 
 its external structure. On fig. 41 is shown a portion 
 of one of the parachute hairs much more magnified. 
 
 The seed of the common Dandelion, so dear to 
 children in their play-hours, when they amuse them- 
 selves by puffing at the white plumy globes which tip 
 the ripe dandelion flower-stalks, is a very interesting 
 object even to their parents, on account of its beauti- 
 
VII. 
 
WINGED SEED, 85 
 
 ful structure, and the wonderful way in which it is 
 adapted to the place which it fills. Fig. 45 represents 
 the seed portion of one of these objects, together with 
 a part of the parachute stem, the remainder of that 
 appendage being shown lying across the broken stem. 
 
 The shape of the seed is not unlike that of the 
 valerian, but it is easily distinguished from that 
 object by the series of sharp spikes which fringe its 
 upper end, and which serve to anchor the seed firmly 
 as soon as it touches the ground. From this end of 
 the seed proceeds a long slender shaft, crowned at its 
 summit by a radiating plume of delicate hairs, each of 
 which is plentifully jagged on its surface, as may be 
 seen in fig. 46, which shows a small portion of one of 
 these hairs greatly magnified. These jagged points are 
 evidently intended to serve the same purpose as the 
 spikes below, and to arrest the progress of the seed as 
 soon as it has found a convenient spot. 
 
 Fig. 42 is the seed of the Foxglove, and fig. 43 the seed 
 of the Sunspurge or Milk wort. Fig. 47 shows the seed of 
 the yellow Snapdragon ; remarkable for the membranous 
 wing with which the seed is surrounded, and which is 
 composed of cells with partially spiral markings. When 
 viewed edgewise, it looks something like Saturn with 
 his ring, or to use a more homely, but perhaps a more 
 intelligible simile, like a marble set in the middle of a 
 
86 MOUNTING IN CANADA BALSAM. 
 
 penny. Fig. 48 is a seed of Mullein, covered with net- 
 like" markings on its external surface. These are 
 probably to increase the strength of the external coat, 
 and are generally found in the more minute seeds. 
 
 On fig. 50 is shown a .seed of the Burr-reed ; a 
 structure which is remarkable for the extraordinary 
 projection of the four outer ribs, and their powerful 
 armature of reverted barbs. Fig. 51 shows another 
 form of parachute seed, found in the Willow-herb, where 
 the parachute is not expanded nearly so widely as that 
 of the valerian ; neither is it set upon a long slender 
 stem like that of the dandelion, but proceeds at once 
 from the top of the seed, \\idening towards the ex- 
 tremity, and having a very comet-like appearance. 
 Two more seeds only remain, fig. 49 being the seed of 
 Robin Hood, and the other, fig. 52, that of the Musk- 
 mallow, being given in consequence of the thick coat of 
 hairs with which it is covered. 
 
 Many seeds can be well examined when mounted in 
 Canada balsam, the manner of performing which task 
 is simple enough, and yet is often very perplexing 
 to a beginner. 
 
 VERY little apparatus is required. A sixpenny bottle 
 of the best balsam, a spirit-lamp, a metal-plate standing 
 on four legs, so as to form a little table about four 
 
PUTTING ON THE COVER. 
 
 87 
 
 inches in height, some ether, spirits of turpentine, and 
 liquor potassae in bottles, are all the essentials, besides 
 a supply of slides and thin glass covers. The great 
 difficulty in mounting objects in Canada balsam is to 
 keep them free from air-bubbles ; but by proceeding 
 in the following manner, very little difficulty will be 
 found. 
 
 Take one of the curved dipping tubes, put some 
 balsam into it, cork up the wide end and let it stand 
 on its head until wanted. Lay the glass slide on the 
 metal table, light the spirit-lamp, and place it under 
 the table so as to warm the slide throughout, but not 
 to overheat it. Then take the seed, put it into the 
 spirit of turpentine, and let it wait there while the 
 slide is being warmed. 
 
 The next process is to remove the lamp, and to hold 
 
 PUTTING UP AN OBJECT IN A CELL OB CANADA BALSAM. 
 
 the glass tube containing the balsam over the flame, 
 when the balsam will immediately .run towards the 
 orifice, and a drop will ooze out. This drop should be 
 
88 FIXING THE COVER. 
 
 placed on the centre of the slide, and the seed taken 
 out of the turpentine, laid on the warm balsam, and 
 gently pressed into it with one of the dissecting needles. 
 With the needle turn the seed about a little, so as to 
 make sure that no air-bubbles are clinging to its surface, 
 and then take a piece of perfectly clean thin glass, 
 warm it over the spirit-lamp, and lay it on the balsam 
 in the manner here shown. Lower the glass very care- 
 fully, and slowly cover the balsam ; or when you come 
 to press it down, the object will shoot out at the side, 
 and all your trouble have to be taken over again. 
 When you have laid it nicely level, press it down with 
 the separated points of your curved forceps, and sec 
 that no bubbles have made their appearance. Having 
 satisfied yourself about this matter, lay a small circular 
 piece of thick pasteboard or a slice of a small cork 
 on the glass cover, put it within the jaws of one of 
 those American paper clips which you can get in 
 almost any stationer's shop for a penny, let the clip 
 close gradually, and lay it aside to harden. Another 
 simple mode of holding the thin glass cover firmly on 
 the slide is by tying two pieces of whalebone together 
 as in the engraving, and placing the slide between them, 
 a piece of cork or pasteboard being previously laid on 
 the cover as already recommended. 
 
 During the pressing process a large amount of balsam 
 
FINISHING THE SLIDE. 
 
 89 
 
 will be squeezed around the edges of the thin glass, and 
 may easily be removed by scraping it with the heated 
 blade of an old knife kept for the purpose, and then 
 rubbing the edges clean with a rag moistened with 
 ether or spirits of turpentine. 
 
 Some structures require to be soaked for a consider- 
 able time in turpentine, and others in liquor potassse, 
 before they can be made sufficiently transparent to be 
 mounted. The ether will be found very useful for 
 cleaning the balsam from the fingers and points of the 
 needles, and is, moreover, of great service in removing 
 the unpleasant smell that results when turpentine is 
 
 SLIDE HOLDER. 
 
 spilt on the hands. If, in spite of all precaution, air- 
 bubbles will make their appearance in the balsam, try 
 to stir them to the top with one of the needles, and 
 then break them by heating the needle and touching 
 them with the point. 
 
 After waiting until the balsam is quite hard-set, 
 which will not safely take place for six or eight hours, 
 and is most certain when suffered to remain quiet for a 
 
90 DRY MOUNTING. 
 
 night or two, the slide may be cleaned as directed above, 
 and either kept as it is or covered neatly with paper, 
 perforated on the spot where the object appears. The 
 microscopist should be careful to label every preparation 
 as soon as it is made, and it is best to write with ink on 
 one end of the slide before proceeding to put up the 
 object upon it, and to wash off the writing just before 
 the label is affixed. A little want of such precautions 
 will cause great confusion and loss of time, and often 
 renders a valuable collection quite useless. 
 
 The dry mode of preparing permanent objects for 
 the microscope is much more simple, and is managed as 
 follows. 
 
 After taking care that the object itself, the slide, and 
 the thin glass are quite clean, put a little dot of ink in 
 the very centre of the slide, on the opposite side to the 
 object, and immediately below the place which it is 
 intended to occupy, so as to act as a guide during the 
 process. Lay the object carefully over the ink dot, 
 place the thin glass very lightly upon it, and fasten it 
 down with two or more strips of thin paper pasted or 
 gummed round its edges. Some persons prefer to 
 fasten it with gold size ; but I have always found the 
 paper to answer quite as well, and not to be nearly so 
 troublesome. 
 
 Now lay it aside to dry, and get ready a piece of 
 
PAPER COVERS. 91 
 
 small-patterned ornamental paper, with a hole punched 
 through it just where it comes upon the object. The 
 easiest plan is to cut a large supply of paper covers, and 
 make the holes with a common gun-wad punch. In 
 order to save materials and space, I frequently mount 
 two dry objects in the same slide, one at each end, and 
 ticket them on a rather large label pasted in the inter- 
 mediate space between them. When the object is 
 firmly fixed, take some thin coloured paper, blue or red 
 is the best, and cover all the edges of the slide with it, 
 pressing it very closely upon the glass, and then apply 
 two of the ornamental paper covers, one above and the 
 other below, so that the two holes are opposite each 
 other, smooth them carefully down, and lay them aside. 
 Covers, stamped and punched for the purpose, are sold 
 at most of the opticians', but I recommend every one to 
 depend as little as possible on his purse, and as much 
 as possible on his fingers. 
 
 As we are speaking of the mode of preparing per- 
 manent objects for the microscope, we may as well 
 glance at another method which is extremely useful in 
 many cases which require much more care and time 
 than with the dry mode or the Canada balsam. It is 
 termed mounting in cells, and is principally employed 
 for those objects which require to be immersed in fluid. 
 
 The cells in which the fluid is contained are made in 
 
92 GLASS AND VARNISH CELLS. 
 
 various ways, some being hollows sunk in the glass 
 slide, others built up like glass boxes, by the aid of 
 cement at their edges j others being made of glass tubes 
 cut into segments, and cemented firmly on the slide ; 
 and others, of a ring of varnish in which the fluid 
 is contained, thus forming very shallow cells holding a 
 mere film of fluid. The first kind of cell can easily be 
 obtained by purchase, as the slides are made expressly 
 by the glass manufacturers. As, however, they are not 
 one whit more useful than the mere varnish cells, they 
 need no further mention. 
 
 The " built-up " cells are made of slips of glass cut 
 to the required size, and laid flat upon the slide if the 
 cell is to be a shallow one, and set on their edges if 
 a deep cell is required. The cements used for this 
 purpose are various, and seem to answer according 
 to the hand which uses them, each person preferring 
 his own mode. Marine glue is an admirable cement, 
 especially for deep cells, but it requires a very high 
 temperature to get it to work freely, and the risk 
 of scorching the fingers is rather great, as I can 
 personally testify. 
 
 Whatever cement may be used with deep cells, it is 
 always better to fasten narrow strips of glass over the 
 junctions, and a triangular slip at each interior angle 
 adds greatly to the strength of the fabric. The great 
 
TUBE AND CEMENT CELLS. 93 
 
 fault of these deep cells is their unpleasant habit of 
 leaking after a while, and the consequent admission of 
 air-bubbles. As, however, they are very seldom re- 
 quired for the microscope, the amateur may as well 
 purchase the few that he will want, and only matte 
 those of easy manufacture. 
 
 The tube-cells are easily made by cutting a glass tube 
 into pieces of the required length, grinding down each 
 surface on a level stone with water, and cementing one 
 end to the glass slide. The tubes are easily cut by 
 notching them with a file, and then running a hot 
 iron round them, when they are tolerably sure to break 
 off level. At first, they are apt to crack upwards or 
 downwards, but a little practice soon sets matters right. 
 Tubes fit for this purpose can be obtained at an easy 
 rate at any glass manufacturer's, circular, oval, or 
 squared, and almost of any needful diameter. Some 
 very large cells made by a friend of mine were cut out 
 of bottles, but I never could master the art of their 
 manufacture myself, the glass always splitting in a 
 wrong direction. 
 
 The most useful cell, and that which is in general 
 use among microscopists, is the cement cell, which is 
 nothing more than a ring of cement drawn on the 
 slide, which, when hard, holds the fluid. Some persons 
 who do not care for appearances make their cells 
 
94 TURNTABLE. 
 
 square, by drawing the figure on the glass with a pen, 
 or laying the slide upon a square ready drawn on paper, 
 and then painting the varnish upon it. The circular 
 cell is, however, much neater, and can be made by sub- 
 stituting a circle for the square, and painting the 
 cement neatly upon the line, taking care not to let the 
 brush trespass within the circle. 
 
 A very neat little apparatus, invented by Mr. Shad- 
 bolt, is used for making circular cells, and can be pur- 
 chased for five shillings, or constructed by a little 
 ingenuity. It is called a turn-table, and consists 
 merely of a horizontal revolving plate of metal, on 
 which the slide is laid, and fastened with two clips 
 while the table revolves. The centre of the slide must 
 of course be brought over the centre of the table, and 
 then, if the brush, charged with varnish or cement, is 
 held to the slide, it immediately strikes a perfect circle, 
 which may be made smaller or larger, according to the 
 distance of the brush from the centre. Generally, the 
 turn-table spins by its own weight, when propelled by 
 the hand, but the addition of a multiplying wheel 
 is very simple, and makes a much more convenient 
 form of apparatus. The ring of cement must be 
 made very wide, and nicely flattened on the upper 
 surface. 
 
 Cells of thin glass are sometimes made, but are of 
 
MOUNTING OBJECTS IN CELLS. 95 
 
 no very great value, the varnish cells answering every 
 purpose quite as well. 
 
 The practical microscopist will find it useful to devote 
 a spare hour or so to the manufacture of a few dozen 
 cells of different sizes and depths, the depth of course 
 being in proportion to the number of layers of cement. 
 They should be put away in some place where dust 
 will .not reach them, and they will then be quite hard 
 and ready for the reception of the fluid when needed. 
 
 The method of mounting an object in a cell is as 
 follows : 
 
 Pour into the cell a little of the fluid in which the 
 object is to be mounted, and then lay the object care- 
 fully within it. Sometimes, if it is of a very delicate 
 structure, the best plan is to immerse the whole slide 
 in the fluid, float the object into the cell, and then lift 
 it all out together. This precaution, however, is very 
 seldom needed. Having laid the object in the cell, 
 pour some more of the fluid upon it, and fill it up like 
 a " bumper " of wine, letting the fluid stand well above 
 the level of the cell. Lay it aside for a time in, order 
 to let all air-bubbles rise to the surface, and be sure to 
 covfer it with a shade, or put it in some place where the 
 dust will not get into the cell. 
 
 A very expeditious mode of getting rid of the 
 bubbles is to place the cell in the receiver of an air- 
 
96 
 
 COVERING THE CELLS. 
 
 AIR-PUMP. 
 
 pump, when, after a very few strokes, all the bubbles 
 will come to the surface, break, and disappear. An 
 air-pump, such as that represented in the engraving, 
 is made by Mr. Baker, of Holborn, for a small sum. 
 
 Having been quite satisfied that the bubbles have 
 been expelled, take a circular thin glass cover, not 
 quite large enough to reach to the outer edges of the 
 ring of cement, and lay it carefully on the cell, in the 
 manner employed in mounting an object in Canada 
 balsam, page 87. When it lies quite level, take some 
 blotting paper, and oarefully dry up the superfluous 
 
VARNISHES AND THEIR APPLICATION. 97 
 
 fluid which will have run out of the cell, and which 
 must be totally removed before the cover can be 
 fastened down. 
 
 When the edges of the cover are perfectly dry, hold 
 it down with the forceps with the left hand, and paint 
 a thin layer of gold-size all round the edge of the 
 cover, so as to fasten it to the cell. Do no more to it 
 for at" least six hours, but lay a little weight of lead a 
 bullet with a flattened side answers admirably on the 
 cover, and leave it to harden. After a sufficient lapse 
 of time, another layer of varnish may be added, until 
 the cover is hermetically sealed on the cell, and neither 
 air can enter nor fluid escape. Unless the first layers 
 of varnish be extremely thin, and very little material 
 used, it is sure to run into the cell, and mar the beauty 
 of the preparation : asphalte varnish is best for the few 
 last layers. In all cases, another coat of varnish after 
 the lapse of a few months can do no harm, and may 
 save a really valuable object. 
 
 Sealing-wax varnish is often useful for the double 
 purpose of cementing and giving a neat outside to pre- 
 parations, and is made by breaking the best black or 
 red sealing-wax into little pieces, pouring spirits of 
 wine over them, and letting them dissolve. The bottle 
 should be frequently shaken, as the sealing-wax is apt 
 to settle at the bottom. It is very useful when time is 
 
 H 
 
98 PRESERVATIVE FLUIDS. 
 
 a matter of consideration, as the spirit evaporates very 
 
 quickly, and the varnish will become quite hard in a 
 
 very few minutes. 
 
 The fluids employed for mounting many soft objects 
 
 are very various ; some of the best and most easily 
 
 made are here given. 
 
 For vegetable tissues, algae, &c. : 1. Distilled water 
 
 with a little camphor. 2. Distilled water with a little 
 
 corrosive sublimate. This substance is very useful in 
 preventing the growth of fungi, which are apt to deve- 
 lop themselves in preparations, and totally disfigure the 
 object therein. The microscopist can, however, take 
 an appropriate revenge by magnifying and drawing 
 them. 3. Distilled water 1 ounce, salt 5 grains, a very 
 little corrosive sublimate. 4. Glycerine, either pure or 
 dissolved in water, in various proportions. Deane's 
 gelatine is very handy for vegetables, as they can be 
 placed in it while wet, and only need to be laid on a 
 warm slide, covered with a drop of gelatine, and then 
 covered with thin glass as if they were set in Canada 
 balsam. There are many other fluids employed by 
 different microscopists, but these are amply sufficient 
 for all ordinary purposes. 
 
 For animal tissues : 1. Chloride of zinc 20 grains, 
 distilled water 1 ounce. This is one of the best sub- 
 stances known for this purpose. 2. Goadby's solution, 
 
PRESERVATIVE FLUIDS. 99 
 
 No. 1. Bay-salt 4 ounces, alum 2 ounces, corrosive 
 sublimate 2 grains, boiling distilled water 1 quart. 
 This is the strongest and most astringent of his three 
 solutions, and is not very often employed. 3. Goad by 's 
 solution, No. 2. Same as the preceding, except that 
 there are 4 grains of corrosive sublimate, and the 
 quantity of water is doubled. Various modifications 
 of this fluid can be made, so as to suit particular 
 objects. Spirit should be avoided in cells as much as 
 possible, as in process of time it is tolerably sure to 
 make its way through the cement. Canada balsam 
 is useful both for the harder vegetable and animal 
 substances, and has already been mentioned. For 
 mounting many crystals, castor oil is a very good 
 preservative, but Canada balsam answers admirably in 
 most instances. 
 
100 
 
 CHAPTER V. 
 
 ALG2G AND THEIR GROWTH DESMIDIACE^E, WHERE FOUND 
 DIATOMS, THEIR FLINTY DEPOSIT VOL VOX MOULD, BLIGHT, 
 AND MILDEW MOSSES AND FERNS MARE'S-TAIL AND THE 
 SPORES COMMON SEA-WEEDS AND THEIR GROWTH. 
 
 ON Plate IV. will be seen many examples of the 
 curious vegetables called Algae, which exhibit some of 
 the lowest forms of vegetable life, and are remarkable 
 for their almost universal presence in all parts of this 
 globe, and also almost all conditions of cold, heat, or 
 climate. Many of them are well known under the 
 popular name of Sea-weeds, others are equally familiar 
 under the titles of "mould," "blight," or "mildew," 
 while many of the minuter kinds exhibit such capability 
 of motion, and such apparent symptoms of volition, 
 that they have been long described as microscopic 
 animalcules, and thought to belong to the animal 
 rather than to the vegetable kingdoms. 
 
 Fig. 1 represents one of the very lowest forms of 
 vegetable life, being known to the man of science as 
 the Palmella, and to the general public as " Gory dew." 
 
CONJUGATION. 1*0 1 
 
 It may be seen on almost any damp wall, extending in 
 red patches of various sizes, looking just as if some 
 blood had been dashed on the wall, and allowed to dry 
 there. With a tolerably powerful lens, this substance 
 can be resolved into the exceedingly minute cells 
 depicted in the figure. Generally, these cells are single, 
 but in many instances they are double, owing to the 
 process of subdivision by which the plant grows, if 
 such a term may be used. 
 
 Fig. 2 affords an example of another very low form 
 of vegetable, the Palmoglsea, or that green slimy 
 substance which is so common on damp stones. When 
 placed under the microscope, this plant is resolvable 
 into a multitude of green cells, each being surrounded 
 with a kind of gelatinous substance. The mode of 
 growth of this plant is very simple. A line appears 
 across one of the cells, and after a while it assumes a 
 kind of hour-glass aspect, as if a string had been tied 
 tightly round its middle. By degrees the cell fairly 
 divides into two parts, and then each part becomes 
 surrounded with its own layer of gelatine, so as to form 
 two separate cells joined end to end. 
 
 One of the figures, that on the right hand, represents 
 the various processes of " conjugation/' i.e. the reunion 
 and fusion together of the cells. Each cell throws out 
 a little projection, which meet together, and then 
 
102 PKOTOCOCCUS. 
 
 uniting form a sort of isthmus, cementing the two 
 main bodies. By rapid degrees this neck widens, until 
 the two cells become fused into one large body. The 
 whole subject of conjugation is very interesting, and 
 may be seen treated at great length in the Micrographic 
 Dictionary of Messrs. Griffith and Henfrey, a work to 
 which the reader is referred for further information on 
 many of the subjects that, in this small work, can 
 receive but a very hasty treatment. 
 
 Few persons would suppose that the slug-like object 
 on fig. 3, the little rounded globules, with a pair of 
 hair-like appendages, and the round disc with a dark 
 centre, are only different forms of the same being. 
 Such, however, is the case, and these are three of the 
 modifications which the Protococcus undergoes. This 
 vegetable may be seen floating like green froth on the 
 surface of rain-water. 
 
 On collecting some of this froth and putting it under 
 the microscope, it is seen to consist of a vast number 
 of little green bodies, moving briskly about in all 
 directions, and guiding their course with such apparent 
 exercise of volition, that they might very readily be 
 taken for animals. It may be noticed that the colour 
 of the plant is sometimes red, and in that state it has 
 been called the Hsematococcus. 
 
 The "still" state of this plant is shown in the 
 
STILL AND MOTILE STATES. 103 
 
 round disc. After a while the interior substance 
 splits into two portions ; these again subdivide, and 
 the process is repeated until sixteen or thirty-two cells 
 become developed out of the single parent cell. These 
 little ones then escape, and being furnished with two 
 long "cilia" or thread-like appendages, whirl them- 
 selves merrily through the water. When they have 
 spent some time in this state, they lose the cilia, 
 become clothed with a strong envelope, and pass into 
 the still stage from which they had previously emerged. 
 This curious process is repeated in endless succession, 
 and causes a very rapid growth of the plant. The 
 moving bodies are technically called zoospores, or 
 living spores, and are found in many other plants 
 besides those of the lowest order. On fig. 13 is de- 
 lineated a very minute plant, called from its colour 
 Chlorococcus. It may be found upon tree-trunks, 
 walls, &c. in the form of green dust, and has recently 
 been found to be the first stage of lichens. 
 
 A large and interesting family of the "confervoid 
 algae,' 7 as these low forms of vegetable life are termed, 
 is called the Desmidiacese, or in more common parlance 
 Desmids. A few examples of this family are given in 
 Plate IV. 
 
 They may be found in water, always preferring the 
 cleanest and the brightest pools, mostly congregating in 
 
1 04 CLOSTERIA. 
 
 masses of green film at the bottom of the water, or 
 investing the stems of plants. Their removal is not 
 very easy, but is best accomplished by very carefully 
 taking up this green slippery substance in a spoon, and 
 straining the water away through fine muslin. For 
 preservation, glycerine and gelatine seem to be the best 
 fluids. A very full and accurate description of these 
 plants may be found in Ralfs's " British Desmidieee." 
 
 Fig. 4 represents one of the species of Closterium, 
 more than twenty of which are known. These beauti- 
 ful objects can be obtained from the bottom of almost 
 every clear pool, and are of some interest on account 
 of the circulating currents that may be seen within 
 the living plants. A high power is required to see 
 this phenomenon clearly. The Closteria are repro- 
 duced in various ways. Mostly they divide across the 
 centre, being joined for a while by two half-cells. 
 Sometimes they reproduce by means of conjugation, 
 the process being almost entirely conducted on the 
 convex sides. Fig. 5 represents the end of a Closte- 
 rium, much magnified in order to show the active 
 moving bodies contained within it. 
 
 Fig. 16 is a supposed Desmid, called by the long 
 name of Ankistrodesmus, and presumed to be an earlier 
 stage of Closterium. 
 
 Fig. 6 is a very pretty Desmid called the Pediastrum. 
 
CURIOUS MODE OP GROWTH. 105 
 
 and is valuable to the microscopist as exhibiting a 
 curious mode of reproduction. The figure shows a 
 perfect plant composed of a number of cells arranged 
 systematically in a star-like shape ; fig. 15 is the 
 same species without the colouring matter, in order to 
 show the shape of the cells. The Pediastrum repro- 
 duces by the continual subdivision of the contents 
 of each cell into a number of smaller cells, termed 
 " gonidia " on account of their angular shape. When 
 a sufficient number has been formed, they burst 
 through the envelope of the original cell, taking with 
 them a portion of its internal layer so as to form a 
 vesicle, in which they move actively. In a few minutes 
 they arrange themselves in a circle, and after a while 
 they gradually assume the perfect form, the whole pro- 
 cess occupying about two days. Fig. 18 exhibits an 
 example of the genus Desmidium. In this genus the 
 cells are either square or triangular in their form, 
 having two teeth at their angles, and twisted regularly 
 throughout their length, causing the wavy or oblique 
 lines which distinguish them. The plants of this 
 genus are common, and may be found almost in any 
 water. I may as well mention that I have obtained 
 nearly all the preceding species, together with many 
 others, from a little pond on Blackheath. 
 
 Fig. 7 is another Desmid called Scenedesmus, in 
 
106 GROWTH OF COSMAEIUM. 
 
 which the cells are arranged in rows of from two to 
 ten in number, the cell at each extremity being often 
 furnished with a pair of bristle-like appendages. Fig. 14 
 is another species of the same plant, and both may be 
 found in the water supplied for drinking in London, 
 as well as in any pond. 
 
 A common species of Desmid is seen at fig. 12, 
 called Sphserozosma, looking much like a row of 
 stomata set chainwise together. It grows by self- 
 division. 
 
 Fig. 17 is a specimen of Desmid named Cosmarium, 
 plentifully found in ponds on heaths and commons, 
 and having a very pretty appearance in the microscope 
 with its glittering green centre and beautifully trans- 
 parent envelope. The manner in which the Cosmarium 
 conjugates is very remarkable, and is shown at fig. 19. 
 
 The two conjugating cells become very deeply cleft, 
 and by degrees separate, suffering the contents to pour 
 out freely, and, as at present appears, without any 
 envelope to protect them. The mass, however, soon 
 acquires an envelope of its own, and by degrees as- 
 sumes a dark reddish brown tint. It is now termed 
 a sporangium, and is covered with a vast number of 
 projections, which in this genus are forked at their 
 tip, but in others, which also form sporangia, are 
 simply pointed. The Glosteria conjugate after a some- 
 
ZYGNEMACE^B. 1 07 
 
 what similar manner, and it is not unfrequent to find 
 a pair in this condition, but in their case the sporangium 
 is quite smooth on its surface. 
 
 Another very remarkable family of confervoid algse 
 is that which is known under the name of Oscillatorise, 
 from the oscillating movement of the plant. They 
 are always long and filamentous in character, and may 
 be seen moving up and down with a curious irregu- 
 larity of motion. Their growth is extremely rapid, and 
 may be watched under a tolerably powerful lens, thus 
 giving many valuable hints as to the mode by which 
 these plants are reproduced. One of the commonest 
 species is represented at fig. 8. Dr. Carpenter is of 
 opinion that the Oscillatoriae may be the earlier or 
 " motile " forms of some more perfect plants. 
 
 Figs. 9, 10, and 11 are examples of another family, 
 called technically the Zygnemacese, because they are 
 so constantly yoked together by conjugation. They 
 all consist of a series of cylindrical cells set end to end, 
 and having their green contents arranged in equal 
 patterns. Two of the most common and typical species 
 are here given. 
 
 Fig. 9 is the Spirogyra, so called from the spiral 
 arrangement of the pattern ; and fig. 10 is the Tynda- 
 ridea, or Zygnema as it is called by some writers. A 
 casual inspection will show how easy it is to separate 
 
108 DIATOMS. 
 
 the ona from the other. Fig. 11 represents a portion 
 of the Tyndaridea during the process of conjugation, 
 showing the tube of connexion between the cells and 
 one of the spores. 
 
 WE now arrive at the Diatoms, so called because of 
 their extreme brittleness and the ease with which they 
 may be cut or broken into their component cells. The 
 commonest of those plants is the Di&toma vulgare, 
 seen in fig. 21 as it appears while growing. The re- 
 production of this plant is by splitting down the centre, 
 each half increasing to the full size of the original cell ; 
 and in almost every specimen of water taken from a 
 pond, examples of this diatom undergoing the process 
 of division will generally be distinguished. It also 
 grows by conjugation. The diatoms are remarkable 
 for the delicate shell of flinty matter which incrusts 
 the cell-membranes, and which will retain its shape 
 even after intense heat and the action of nitric acid. 
 While the diatoms are alive, swimming through the 
 water, their beautiful markings are clearly distinct, 
 glittering as if the form were spun from crystalline 
 glass. Just above the figure, and to the right hand, 
 are two outlines of single cells of this diatom, the one 
 showing the front view and the other the profile. 
 
 Fig. 20 is an example of a diatom Cocconema 
 
FLINTY DEPOSIT. 109 
 
 lanceolatum furnished with a stalk. The left-hand 
 branch sustains a "frustule" exhibiting the front view, 
 while the other is seen sideways. 
 
 Another common diatom is shown in fig. 23, and 
 is known by the name of Synedra. This constitutes 
 a very large genus, containing about seventy known 
 species. In this genus the frustules are at first arranged 
 upon a sort of cushion, but in course of time they 
 mostly break away from their attachment. In some 
 species they radiate in every direction from the cushion, 
 like the spikes of the ancient cavalier's mace. 
 
 Fig. 24 is another stalked diatom called Gompho- 
 nema acuminatum, found commonly in ponds and 
 ditches. There are nearly forty species belonging to 
 this genus. A pair of frustules are also shown which 
 have been treated with nitric acid and heat, and ex- 
 hibit the beautiful flinty outline without the coloured 
 contents, technically called endochrome. 
 
 Fig. 27 is a side view of a beautiful diatom, called 
 Eunotia diade*ma from its diadem-like form. There 
 are many species of this genus. When seen upon the 
 upper surface, it looks at first sight like a mere row of 
 cells with a band running along them ; but by careful 
 arrangement of the light, its true form may easily be 
 made out. This specimen has been boiled iu nitric 
 acid. 
 
1 1 DIATOMS. 
 
 Fig. 28 represents a very common fresh- water 
 diatom, named Melosira varians. The plants of this 
 genus look like a cylindrical rod composed of a variable 
 number of segments, mostly cylindrical, but sometimes 
 disc-shaped or rounded. An end view of one of the 
 frustules is seen at the left hand, still coloured with 
 its dots of " endochrome," and showing the cylindrical 
 shape. Immediately above is a figure of another 
 frustule seen under both aspects, as it appears after 
 having been subjected to the action of heat or nitric 
 acid. 
 
 A rather curious species of diatom, called Cocconei's 
 pediculus, is seen at fig. 29 as it appears on the surface 
 of common water-cress. Sometimes the frustules, which 
 in all cases are single, are crowded very closely upon 
 each other and almost wholly hide the substance on 
 which they repose. Fig. 30 is another diatom of a 
 flag-like shape, named Achnanthes, having a long 
 slender filament attached to one end of the lower 
 frustule and standing in place of the flag-staff. There 
 are many wonderful species of such diatoms, some run- 
 ning almost end to end like a bundle of sticks, and 
 therefore called Bacillaria ; others spreading out like a 
 number of fans, such as the genus Licmophora ; while 
 some assume a beautiful wheel-like aspect, of which the 
 genus Meridion affords an excellent example. 
 
VOLVOX. Ill 
 
 The last of the diatoms which we shall be able to 
 mention in this work is that represented on fig. 31. 
 The members of this genus go by the name of Navi- 
 cula, on account of their boat-like shape, and their 
 habit of swimming through the water in a canoe-like 
 fashion. There are many species of this genus, all of 
 which are notable for the graceful and varied courses 
 formed by their outlines, and the extreme delicacy of 
 their markings. 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 illumination, so that they serve as test objects 
 whereby the performance of a microscope can be 
 judged by a practical man. 
 
 THE large spherical figure in the centre of Plate IY. 
 represents an example of a family belonging to the 
 confervoid algae, and known by the name of Volvox 
 globator. There seems to be but one species known. 
 
 This singular plant has been greatly bandied about 
 between the vegetable and animal kingdoms, but 
 seems now to be satisfactorily settled among the 
 vegetables. In the summer it may be found in pools 
 of water, sufficiently large to be visible to the naked 
 eye like a little green speck proceeding slowly through 
 the water. When a moderate power is used, it appears 
 
112 MOULD, BLIGHT, AND MILDEW. 
 
 as shown in the figure, and always retains within its 
 body a number of smaller individuals, which after a 
 while burst through the envelope of the parent, and 
 start into independent existence. On a closer exami- 
 nation, a further generation may be discovered even 
 within the bodies of the children. The whole surface 
 is profusely covered with little green bodies, each being 
 furnished with a pair of movable cilia, by means of 
 which the whole affair is moved through the water. 
 These bodies are analogous to the zoospores already men- 
 tioned, and are connected with each other by a net- 
 work of filaments. A more magnified representation 
 of one of the green bodies is shown immediately above 
 the larger figure. The Volvox is apt to die soon, when 
 confined in a bottle. 
 
 Fig. 25 is the common Yeast-plant, consisting simply 
 of a chain of spores, and supposed by some authors to 
 be a state of the ordinary blue mould. Fig. 26 is a 
 curious object, presumed to be one of the confervoid algae, 
 and found in the human stomach, where it probably 
 gets by means of the water used for drinking. It may 
 possibly be a blanched form of some fresh- water alga. 
 Its scientific name is Sarcina ventriculi. 
 
 We now come upon a few of the Blights and Mil- 
 dews. Fig. 32 is the Ure'do, or red-rust of wheat. 
 Another species is very common on the Bramble-leaf, 
 
MOSSES AND FERNS. 113 
 
 vhere it appears in spots which at first are red, then 
 orange, and at last become reddish black. Another 
 species of Uredo, together with a Phragmidium, once 
 thought to be another kind of fungus, is seen on a 
 Rose-leaf on Plate V. fig. 1. On fig. 10, however, of the 
 same plate, the Phragmidium may be seen proceeding 
 from Uredo, thus proving them to be but two states of 
 the same plant. Fig. 33 is the mildew of corn, called 
 Puccinia by scientific writers. Another species of 
 Puccinia, found on the Thistle, is shown in Plate V. 
 fig. 7. Fig. 34 is the. mould found upon decaying 
 grapes, and called therefrom, or from the clustered 
 spores, Botrytis. Some of the detached spores are seen 
 by its side. Fig. 35 is another species of the same 
 genus, termed Botrytis parasitica, and is the cause of 
 the well-known " potato disease." 
 
 The Mosses and Ferns afford an endless variety of 
 interesting objects to the microscopist ; but as their 
 numbers are so vast, and the details of their structure 
 so elaborate, they can only be casually noticed in the 
 present work. Fig. 38 represents a spore- case of the 
 Polypodium, one of the ferns, as it appears while in the 
 act of bursting and scattering the contents around. 
 One of the spores is seen more magnified below. The 
 spore-cases of many ferns may be seen bursting unddr 
 the microscope, and have a very curious appearance, 
 I 
 
114 ELATERS AND THEIR OFFICE. 
 
 writhing and twisting like worms, and then suddenly 
 filling the field with a cloud of spores. Fig. 9, Plate V., 
 is a piece of the brown, chaff-like, scaly structure 
 found at the base of the stalk of male fern cells, show- 
 ing the manner in which a flat membrane is formed. 
 Fig. 39 is a capsule of the Hypnum, one of the mosses, 
 showing the beautiful double fringe with which its 
 edge is crowned. Fig. 2, Plate V., is the capsule of 
 another moss, Polytrichum, to show the toothed rim; 
 on the right hand is one of the teeth much more 
 magnified. 
 
 Fig. 3, Plate V., is the capsule of the Jungermannia, 
 another moss, showing the "elaters" bursting out on 
 every side, and scattering the spores. Fig. 4 is a single 
 elater much magnified, showing it to be a spirally 
 coiled filament, that, by sudden expansion, shoots out 
 the spores just as a child's toy-gun discharges the arrow. 
 Fig. 5 is a part of the leaf of the Sphagnum moss, 
 showing the curious spiral arrangement of secondary 
 fibre which is found in the cells, as well as the circular 
 pores which are found in each cell at a certain stage of 
 growth. Just below, and to the left hand, is a single 
 cell greatly magnified, in order to show these peculi- 
 arities more strongly. Fig. 8 is part of a leaf of 
 Jungermannia, showing the dotted cells. 
 
 Fig. 6, Plate V., is a part of a rootlet of moss, 
 
SPORES OF MARE'S-TAIL. 115 
 
 showing how it is formed of cells elongated, and joined 
 end to end. 
 
 On the common Mare's-tail, or Eqnise'tum, may be 
 seen a very remarkable arrangement for scattering the 
 spores. On the last joint of the stem is a process called 
 a fruit-spike, being a pointed head, around which are 
 set a number of little bodies just like garden-tables, 
 with their tops outward. One of these bodies, which are 
 called the sporangia, is seen in fig. 40. From the top. of 
 the table depend a number of tiny pouches, lying closely 
 against each other, and containing the spores. At the 
 proper moment these pouches burst from the inside, and 
 fling out the spores, which then look like round balls 
 with irregular surfaces, as shown in fig. 40, c. This irre- 
 gularity is caused by four elastic filaments knobbed at 
 the end, which are originally coiled tightly round the 
 body of the spore, but by rapidly untwisting them- 
 selves, cause the spore to leap about so as to aid in the 
 distribution. A spore with uncoiled filaments is seen 
 at fig. 40, b. By breathing on them they may be made 
 to repeat this process at will. 
 
 Fig. 36 is a common little sea-weed, called Ectocarpus 
 siliculosus, that is found parasitically adhering to large 
 plants, and is given, in order to show the manner in 
 which the extremities of the branches are developed 
 into sporanges. Fig. 37 is a piece of the common Green 
 
116 VARIOUS ALG^E. 
 
 laver, Ulva latissima, showing the green masses that 
 are ultimately converted into zoospores, and by their 
 extraordinary fertility cause the plant to grow with such 
 rapid luxuriance wherever the conditions are favour- 
 able. Every possessor of a marine aquarium knows how 
 rapidly the glass sides become covered with growing 
 masses of this plant. The smaller figure above is a 
 section of the same plant, showing that it is composed 
 of a double plate of cellular tissue. 
 
 Fig. 41 is a piece of Purple laver or "Sloke," Por- 
 phyra laciniata, to show the manner in which the cells 
 are arranged in groups of four, technically named 
 " tetraspores." This plant has only one layer of 
 cells. 
 
 On Plate V. may be seen a number of curious details 
 of the higher Algae. 
 
 Fig. 11 is the Sphacelaria, so called from the curious 
 capsule cells found at the end of the branches, and 
 termed sphacelee. This portion of the plant is shown 
 more magnified in fig. 12. Another sea-weed is repre- 
 sented on fig. 13, in order to show the manner in which 
 the fruit is arranged ; and a portion of the same plant 
 is given on a larger scale at fig. 14. 
 
 A very pretty little sea-weed called Ceramium is 
 shown at fig. 15; and a portion showing the fruit much 
 more magnified is drawn at fig. 22. Fig. 23 is a little 
 
)- 4 
 
 ft 4$ * 
 
 IX. 
 
CERAMIDIA. 117 
 
 alga called Myriouema, growing parasitically on the 
 preceding plant. 
 
 Fig. 16 is a section of a capsule belonging to the 
 Halydris siliquosa, showing the manner in which the 
 fruit is arranged; and fig. 17 shows one of the spores 
 more magnified. 
 
 Fig. 18 shows the Polysiph6nia parasitica, a rather 
 common species of a very extensive genus of sea- weeds, 
 containing nearly three hundred species. Fig. 19 is a 
 portion of the stem of the same plant, cut across in 
 order to show the curious mode in which it is built up 
 of a number of longitudinal cells, surrounding a central 
 cell of large dimensions, so that a section of this plant 
 has the aspect of a rosette when placed under the 
 microscope. A capsule or " ceramidium " of the same 
 plant is shown at fig. 20, for the purpose of exhibiting 
 the pear-shaped spores, and the mode of their escape 
 from the parent- cell preparatory to their own develop- 
 ment into fresh plants. The same plant has another 
 form of reproduction, shown in fig. 21, where the 
 " tetraspores " are seen imbedded in the substance of 
 the branches. There is yet a third mode of reproduc- 
 tion by means of " antheridia," or elongated white sacs 
 at the extremities of the branches. 
 
 Fig. 25 is the Cladophora, a green alga, given to 
 illustrate its mode of growth; and fig. 26 represents 
 
118 ALG^l AND THEIR SPORES. 
 
 one of the red sea-weeds, Ptildta elegans, beautifully 
 feathered, and with a small portion given also on a 
 larger scale, in order to show its structure more fully. 
 A good contrast with this species is seen on fig. 27, and 
 the mode in which the long, slender, filamentary fronds 
 are built up of many-sided cells is seen just to the left 
 hand of the upper frond. Fig. 24 is a portion of the 
 lovely Delesseria sanguiuea, given in order to show the 
 formation of the cells, as also the arrangement by 
 which the indistinct nervures are formed. 
 
 The figure on the bottom left-hand corner of Plate V. 
 is a portion of the pretty Nitophyllum laceratum, a 
 plant belonging to the same family as the preceding. 
 The specimen here represented has a gathering of spores 
 upon the frond, in which state the frond is said to be 
 "in fruit." 
 
 Fig. 27 represents a portion of the common Sea 
 grass (Enter omorpha), so common on rocks and stones 
 between the range of high and low water. On the 
 left hand of the figure, and near the top, is a small 
 piece of the same plant much more magnified, in order 
 to show the form of its cells. 
 
119 
 
 CHAPTER VI. 
 
 ANTENNA, THEIR STRUCTURE AND USE EYES, COMPOUND AND 
 SIMPLE BREATHING ORGANS JAWS AND THEIR APPENDAGES 
 LEGS, FEET, AND SUCKERS DIGESTIVE ORGANS WINGS, SCALES, 
 AND HAIRS EGGS OF INSECTS HAIR, WOOL, LINEN, SILK, AND 
 COTTON SCALES OF FISH FEATHERS SKIN AND ITS STRUCTURE 
 EPITHELIUM NAILS, BONE, AND TEETH BLOOD CORPUSCLES 
 AND CIRCULATION ELASTIC TISSUES MUSCLE AND NERVE. 
 
 WE now take leave of the vegetables for a time, and 
 turn our attention to the animal kingdom. 
 
 On Plafe VI. may be seen many beautiful examples 
 of animal structures, most of them being taken from 
 the insect tribes. We will begin with the antennae, or 
 horns, as they are popularly termed, of the insect. 
 
 The forms of these organs are as varied as those of 
 the insects to which they belong, and in most cases 
 they are so well defined that a single antenna will, in 
 almost every instance, enable a good entomologist to 
 designate the genus to which the insect belonged. The 
 functions of the antenna are not satisfactorily ascer- 
 tained. They are certainly often used as organs of 
 speech, as may be seen when two ants meet each other, 
 
120 ANTENNA, 
 
 cross their antennae, and then start off simultaneously 
 to some task which is too much for a single ant. This 
 pretty scene may be witnessed on any fine day in a 
 wood, and a very animated series of conversations may 
 readily be elicited by laying a stick across their paths, 
 or putting a dead mouse or large insect in their way. 
 
 I once saw a very curious scene of this kind take 
 place at an ant's nest near Hastings. A great Daddy 
 Long-legs had unfortunately settled on the nest, and was 
 immediately " pinned " by an ant or two at each leg so 
 effectually, that all its struggles availed it nothing. 
 Help was, however, needed, and away ran four or five ants 
 in different directions, intercepting every comrade they 
 met, and by a touch of the antennae sending them off 
 in the proper direction. A large number of the wise 
 insects soon crowded round the poor victim, whose fate 
 was rapidly sealed. Every ant took its proper place, 
 just like a gang of labourers under the orders of their 
 foreman ; and by dint of pushing and pulling, the long- 
 legged insect was dragged to one of the entrances of 
 the nest, and speedily disappeared. 
 
 Many of the ichneumon-flies may also be seen 
 quivering their antennae with eager zeal, and evidently 
 using them as feelers, clearly to ascertain the presence 
 of the insect in which they intend to lay their eggs, 
 and many other similar instances will be familiar to 
 
AND THEIR PRESUMED OFFICE. 121 
 
 any one who has been in the habit of watching insects 
 and their ways. 
 
 It is, however, most likely that the antennae serve 
 other purposes than that which has just been men- 
 tioned, and many entomologists are of opinion that 
 they serve as organs of hearing. 
 
 Fig. 15, Plate VI., represents a part of one of the 
 joints belonging to the antennae of the common House- 
 fly, and is seen to be covered with a multitude of little 
 depressions, some being small, and others very much 
 larger. A section of the same antenna, but on a larger 
 scale, is shown by fig. 16, in order to exhibit the real 
 form of these depressions. Nerves have been traced to 
 these curious cavities, which evidently serve some very 
 useful purpose, some authors thinking them to belong 
 to the sense of smell, and others to that of hearing. 
 Perhaps they may be avenues of sensation which are 
 not possessed by the human race, and of which we are 
 therefore ignorant. Fig. 1 7 represents a section of the 
 antennae of an Ichneumon-fly, to show the structure of 
 these organs of sense. 
 
 We will now glance casually at the forms of antennae 
 which are depicted in the plate. 
 
 Fig. 1 is the antenna of the common Cricket, and 
 consists of a vast number of little joints, each a trifle 
 smaller than the preceding, so as to form a long, thread- 
 
122 VARIOUS ANTENNJE. 
 
 like organ. Fig. 2 is taken from the Grasshopper, and 
 shows the joints larger in the middle than at each 
 end. 
 
 Figs. 3 and 5 are from two minute species of Cock- 
 tailed Beetles (Staphylinidce), which swarm throughout 
 the summer months, and even in the winter may be 
 found in profusion under stones and moss. The insect 
 from which fig. 5 was taken is so small that it is 
 almost invisible to the naked eye, and was captured on 
 the wing by waving a sheet of gummed paper under 
 the shade of a tree. These are the tiresome little 
 insects that so often get into the eye in the summer, 
 and cause such pain and inconvenience before they are 
 removed. 
 
 Fig. 4 shows the antenna of the Tortoise Beetle 
 (Cdssida), so common on many leaves, and remarkable 
 for its likeness to the reptile from which it derives its 
 popular name. Fig. 3 is from one of the Weevils, and 
 shows the extremely long basal joint of these beetles, 
 as well as the clubbed extremity. Fig. 7 is the beauti- 
 fully notched antenna of the Cardinal Beetle (Pyroclirba), 
 and fig. 11 is the fan-like antenna of the common Cock- 
 chaffer. This specimen is taken from a male insect, 
 and the reader will find his trouble repaid by mounting 
 one of these antennae as a permanent object. 
 
 It may here be noticed that all these antennae must 
 
MOUNTING ANTENNA. 123 
 
 be mounted in Canada balsam, as otherwise they will 
 be too opaque for the transmission of light through 
 their substance. 
 
 In many cases they are all the better for being 
 soaked for some time in liquor potassae, then dried 
 between two slips of glass, then soaked in turpentine, 
 and lastly put up in the balsam. Otherwise, their 
 characteristics will be totally invisible under the micro- 
 scope, and the observer will be as bewildered as a 
 gentleman of whom I heard, who lately purchased a 
 good microscope, and returned it next day as useless. 
 The maker who had guaranteed it naturally thought 
 that it had been injured by rough treatment, but finding 
 that it performed well in his own hands, he inquired as 
 to the details, and especially as to the object which it 
 would not show. The answer was, that it would not 
 exhibit the crystals of sugar. "How large a crystal 
 did you try?" asked the optician. "A lump out of 
 the sugar-basin," was the answer. ' 
 
 Fig. 12 is an antenna from one of the common 
 Ground Beetles (Cdrabus), the joints looking like a 
 string of elongated pears. The reader will find that in 
 beetles he is sure to find eleven joints in the antennae. 
 
 Fig. 10 is the entire antenna of a fly (Syrphus), one 
 of those pretty flies that may be seen hovering over 
 one spot for a minute, and then darting off like light- 
 
124 ANTENN2E OF BUTTERFLY AND MOTH. 
 
 ning to hang over another. The large joint is the one 
 on which are found those curious depressions that have 
 already been mentioned. Fig. 8 is one of the antennae 
 of a Tortoiseshell Butterfly (Vanessa), showing the 
 slender knobbed form which butterfly antennae assume ; 
 and figs. 13 and 14 are specimens of moth antennae, 
 showing how they always terminate in a point. Fig. 13 
 is the beautiful feathery antennae of the Ermine Moth 
 (Spilosoma) ', and fig. 14 is the toothed antenna of 
 the Tiger Moth (Arctia cajd). In all these feathered 
 and toothed antennae of moths, the male insects have 
 them much more developed than the female, probably 
 for the purpose of enabling them to detect the presence 
 of their mates, a property which some possess in won- 
 derful perfection. The male Oak-egger Moth, for 
 example, can be obtained in any number by putting 
 a female into a box with a perforated lid, placing the 
 box in a room, and opening the window. In the course 
 of the evening seven* or eight males are seen to make 
 their appearance, and they are so anxious to get at 
 their intended mate, that they will suffer themselves to 
 be taken by hand. 
 
 Fig. 9 is an antenna of the male Gnat, a most 
 beautiful object, remarkable for the delicate trans- 
 parency of the joints, and the exquisitely fine feathering 
 with which they are adorned. 
 
SIMPLE AND COMPOUND EYES. 125 
 
 We now arrive at the Eyes of the insects, all of 
 which are very beautiful, arid many are singularly full 
 of interest. 
 
 In the centre of Plate VI. may be seen the front 
 view of the head of a Bee, showing both kinds of eyes, 
 three simple eyes arranged triangularly in the centre, 
 and two large masses of compound eyes at the 
 sides. 
 
 The simple eyes, termed " ocelli," are from one to 
 three in number, and usually arranged in a triangular 
 form between the two compound eyes. Externally they 
 look merely like shining rounded projections, and can 
 be seen to great advantage in the Dragon-flies. The 
 compound eyes may be considered as aggregations of 
 simple eyes, set closely together, and assuming a more 
 or less perfect six-sided form. Their numbers vary very 
 greatly; in some insects, such as the common Fly, 
 there are about four thousand of these eyes, in the Ant 
 only fifty, in the Dragon-fly about twelve thousand, 
 and in one of the Beetles more than twenty-five 
 thousand. 
 
 Fig. 18 shows a portion of the compound eye of the 
 Atalanta Butterfly, and fig. 20 the same organ of the 
 Death's-head Moth. A number of the protecting hairs 
 may be seen still adhering to the eye of the butterfly. 
 Fig. 22 is a remarkably good specimen of the eye of a 
 
126 BREATHING OF INSECTS. 
 
 fly (Heliophilus), showing the nearly-squared facets, the 
 tubes to which they are attached, and portions of the 
 optic nerves. Fig. 23 is part of the compound eye of 
 a lobster, showing the facets quite square. All these 
 drawings were taken by the camera lucida from my 
 own preparations, so that I can answer for their 
 authenticity. 
 
 On Plate VIII. figs. 6 and 12, the reader will find 
 two more examples of eyes, being in these cases taken 
 from the Spiders. Fig. 6 is an example of the eight 
 eyes of the well-known Zebra Spider, so common on 
 our garden walls and similar situations, hunting inces- 
 santly after flies and other prey, and capturing them 
 by a sudden pounce. The eyes are like those of the 
 ocelli of insects, and are simple in their construction. 
 The number, arrangement, and situation of the eyes is 
 extremely varied in spiders, and serves as one of the 
 readiest modes of distinguishing the species. Fig. 12, 
 Plate VIII., represents one of the curious eyes of the 
 common Harvest Spider, as it appears perched on a 
 prominence or " watch-tower," as it has been aptly 
 named, for the purpose of enabling the creature to take 
 a more comprehensive view of surrounding objects. 
 
 i 
 
 RETURNING to Plate VI., on fig. 12 we see a curiously 
 branched appearance, something like the hollow root of 
 
SPIRACLES AND BREATHING TUBES. 127 
 
 a tree, and covered with delicate spiral markings. This 
 is part of the breathing apparatus of the Silkworm, 
 extracted and prepared by myself for the purpose of 
 showing the manner in which the tubes branch off 
 from the " spiracle " or external breathing-hole, a row 
 of which may be seen along the sides of insects, 
 together with the beautiful spiral filament which is 
 wound round each tube for the purpose of strengthen- 
 ing it. One of these spiracles may be seen in the 
 neck of the Gnat (fig. 27). Another spiracle, more 
 enlarged, may be seen on Plate VII. fig. 34, taken 
 from the Wire worm, i.e. the larva of the Skipjack Beetle 
 (Eldter), to show the apparatus for excluding dust and 
 admitting air. The object of the spiral coil is very 
 evident, for as these breathing-tubes extend throughout 
 the whole body and limbs, they would fail to perform 
 their office when the limbs were bent, unless for some 
 especial provision. This is achieved by the winding of 
 a very strong but slender filament between the mem- 
 branes of which the tube is composed, so that it always 
 remains open for the passage of air throughout all the 
 ben dings to which it may be subjected. Flexible tubes 
 for gas and similar purposes are made after the same 
 fashion, spiral metal wire being coiled within the 
 leather case. A little piece of this thread is seen un- 
 wound at the end of a small branch towards the top, 
 
128 HONEY-DEW. 
 
 and this thread is so strong that it retains its elasticity 
 when pulled away from the tube, and springs back into 
 its spiral form. I have succeeded in unwinding a con- 
 siderable length of this filament from the breathing- 
 tube of a Humble Bee. 
 
 Fig. 28 represents the two curious tubercles upon 
 the hinder quarters of the common Green-blight, or 
 Aphis, so very common on our garden plants, as well 
 as on many trees and other vegetation. From the tips 
 of these tubercles exudes a sweet colourless fluid, which, 
 after it has fallen upon the leaves, is popularly known 
 by the name of honey-dew. Ants are very fond of this 
 substance, and are in the habit of haunting the trees 
 upon which the aphides live, for the purpose of sucking 
 the honey-dew as it exudes from their bodies. A drop 
 of this liquid may be seen on the extremity of the 
 lower tubercle. 
 
 The head of the same insect may be seen on fig. 24, 
 where the reader may observe the bright scarlet eye, 
 and the long beak with which it punctures the leaves 
 and sucks the sap. Fig. 29 is the head of the Sheep- 
 tick, exhibiting the organ by which it pierces the skin 
 of the creature on which it lives. Fig. 25 is the head 
 of another curious parasite found upon the Tortoise, 
 
JAWS AND THEIR APPENDAGES. 129 
 
 and remarkable for the powerful hooked apparatus 
 which projects in front of the head. 
 
 Turning to Plate VII. fig. 4, we find the head of a 
 Ground Beetle (Cdrabus), valuable as possessing the 
 whole of the organs of the head and mouth. 
 
 Immediately above the compound eyes are seen the 
 roots of the antennae, those organs themselves being 
 cut away in order to save room. Above these are 
 two pairs of similarly constructed organs termed the 
 " maxillary palpi," because they belong to the lesser 
 teeth, or maxillae, which are seen just within the pair 
 of great curved jaws, called the mandibles, which are 
 extended in so threatening a manner. The "labial 
 palpi," so called because they belong to the " labium," 
 or under lip, are seen just within the others ; the 
 tongue is seen between the maxillae, and the chin or 
 u mentum" forms a defence for the base of the maxillae 
 and ,the palpi. A careful examination of a beetle's 
 mouth with the aid of a pocket lens is very instructive 
 as well as interesting. 
 
 Fig. 1 on the same plate shows the jaws of the Hive 
 Bee, where the same organs are seen modified into 
 many curious shapes. In the centre may be seen the 
 tongue, elongated into a flexible and hair-covered in- 
 strument, used for licking the honey from the interior 
 of flowers. At each side of the tongue are the labial 
 
 K 
 
130 HEADS OP INSECTS. 
 
 palpi, having their outermost joints very small, and the 
 others extremely large, and acting as a kind of sheath 
 for the tongue. Outside the labial palpi are the 
 maxillae, separated in the specimen, but capable of 
 being laid closely upon each other, and the mandibles 
 outside all. 
 
 The curiously elongated head of the Scorpion-fly 
 (Panorpa), seen at fig. 7, affords another example of 
 the remarkable manner in which these organs are 
 developed in different insects. Another elongated 
 head, belonging to the Daddy Long-legs, is seen in 
 Plate VI. fig. 27, and well shows- the compound eyes, the 
 antennae, and the palpi. Fig. 2 represents the coiled 
 tongue of the Atalanta Butterfly, being composed of 
 the maxillae very greatly developed, and having a form 
 as if each had originally been flat, and then rolled 
 up so as to make about three-fourths of a tube. A 
 number of projections are seen towards the tip, and 
 one of these little bodies is shown on a larger scale at 
 fig. 3. These curious organs have probably some con- 
 nexion with the sense of taste. Along the edges of 
 the semi-tubes are arranged a number of very tiny 
 hooks, by means of which the insect can unite the 
 edges at will. 
 
 Fig. 11, in the centre of the plate, shows one of the 
 most curious examples of insect structure, the pro- 
 
THE PROBOSCIS OF INSECTS. 131 
 
 boscis or trunk of the common Bluebottle-fly. The 
 maxillary palpi covered with bristles are seen projecting 
 at each side, and upon the centre are three lancet-like 
 appendages, two small and one large, which are used 
 for perforating various substances on which the insect 
 feeds. The great double disc at the end is composed 
 of the lower lip greatly developed, and is filled with a 
 most complex arrangement of sucking- tubes, in order 
 to enable it to fulfil its proper functions. The nume- 
 rous tubes which radiate towards the circumference are 
 strengthened by a vast number of partial rings of 
 strong filamentary substance, like that which we have 
 already seen in the breathing-tube of the Silkworm. 
 Some of these partial rings are seen on fig. 12, a little 
 above. The mode by which the horny matter compos- 
 ing the rings is arranged upon the tubes is most 
 wonderful, and requires a tolerably high power to 
 show it. 
 
 Fig. 5 shows the tongue of the common Cricket, a 
 most elegantly formed organ, having a number of radia- 
 ting bands covered with zig-zag lines, resulting from 
 the triangular plates of strengthening substance with 
 which they are furnished, instead of the rings. A 
 portion more highly magnified is shown at fig. 6, 
 exhibiting the manner in which the branches are 
 arranged. 
 
 K2 
 
132 LEGS AND FEET. 
 
 THE Legs of insects now claim our attention. 
 
 Fig. 9,. Plate VII, shows the " pro-leg" of a Cater, 
 pillar. The pro-legs are situated on the hinder parts 
 of the caterpillar, and, being set in pairs, take a won- 
 derfully firm hold of a branch or twig, by pressure 
 against each other. Around the pro-legs are arranged 
 a series of sharp hooks, set with their points inwards, 
 for the greater convenience of holding. Fig. 10 repre- 
 sents one of the hooks more magnified. 
 
 Fig. 15 is the lower portion of the many-jointed 
 legs of the Long-legged Spider (Phaldngium), the whole 
 structure looking very like the antenna of the cricket. 
 Fig. 17 is the leg of the Glow-worm, showing the single 
 claw with which it is armed. Fig. 26 shows the foot 
 of the Flea, furnished with two simple claws. Fig. 16 
 is the foot of the Trombidium, a genus of parasitic 
 creatures, to which the well-known Harvest-bug belongs. 
 Fig. 26, Plate VI. , shows the leg of the green Aphis of 
 the geranium, exhibiting the double claw, and the pad or 
 cushion, which probably serves the same purpose as the 
 pad found upon the feet of many other insects. Fig. 8 
 is the lower portion of the leg of the Ant, showing 
 the two claws and the curious pad in the centre, by 
 means of which the insect is able to walk upon slippery 
 surfaces. The Tipula has a foot also furnished with 
 a single pad (see Plate VI. fig. 30). This organ is seen 
 
PADDED FEET. 133 
 
 under a very high power to be covered with long hair- 
 like appendages, each having a little disc at the end, 
 and probably secreting some glutinous fluid which will 
 enable the creature to hold on to perpendicular and 
 smooth surfaces. Many of my readers will doubtlessly 
 have noticed the common Fly towards the end of 
 autumn, walking stiffly upon the walls, and evidently 
 detaching each foot with great difficulty, age and 
 infirmity having made the insect unable to lift its feet 
 with the requisite force. 
 
 Fig. 21 is the foot of one of the Ichneumon-flies 
 (Ophion), the hairy fringe being apparently for the pur- 
 pose of enabling it to hold firmly to the caterpillar in 
 which it is depositing its eggs, and which wriggles so 
 violently under the infliction, that it would soon throw 
 its tormentor, had not some special means been pro- 
 vided for the purpose of keeping its hold. Fig. 20 is 
 a beautiful example of a padded foot, taken from the 
 parasitic creature which is so plentifully found upon 
 the Dor Beetle (Geotrupes), and of which the afflicted 
 insect is said to rid itself by lying on its back near an 
 ant's nest, and waiting until the ants carry off its 
 tormentors. 
 
 Fig. 18 is the foot of the common yellow Dung- 
 fly, so plentiful in pasture lands, and having two 
 claws and two pads; and fig. 19 shows the three pads 
 
134 SUCKERS. 
 
 and two claws found in the foot of the Hornet-fly 
 (Asilus). 
 
 Few microscopic objects call forth such general and 
 deserved admiration as the fore-foot of the male Water - 
 Beetle (Acilius), when properly prepared and mounted, 
 for which see fig. 13. 
 
 On examining this preparation under the microscope, 
 it is found that three of the joints are greatly expanded, 
 and that the whole of their under surface is covered 
 profusely with certain wonderful projections, which are 
 known to act as suckers. One of them is exceedingly 
 large, and occupies a very considerable space, its hairs 
 radiating like the rays of the heraldic sun. Another 
 is also large, but scarcely half the diameter of the 
 former, and the remainder are small, and mounted on 
 the extremities of delicate footstalks, looking some- 
 thing like wide-mouthed trumpets. In the specimen 
 from which the drawing was taken, the smaller suckers 
 are well shown, as they protrude from the margin of 
 the foot. 
 
 The preparation of these feet is a very tiresome 
 business, as the suckers hold so much air, that bubbles 
 are constantly showing themselves, and cannot be easily 
 extirpated without the expenditure of time and much 
 patience. Two specimens of these feet which I pre- 
 pared cost an infinity of trouble, having to be soaked 
 
STOMACH AND GIZZARD OF INSECTS. 135 
 
 in spirits of turpentine, boiled several times in Canada 
 balsam, poked about with needles, and subjected to 
 various treatments before they showed themselves glean 
 and translucent, as they ought to do. 
 
 One of the larger suckers is seen more magnified on 
 fig. 14. 
 
 frlate VIII. fig. 1 well exemplifies the manner in 
 which the muscles of insects do their work, being well 
 attached in the limbs to the central tendon, and pulling 
 " with a will " in one direction, thus giving very great 
 strength. This leg is taken from the Water Boatman 
 (Notonectd), and has been mounted in Canada balsam. 
 
 On Plate VII. fig. 29, may be seen a curiously formed 
 creature. This is the larva of the Tortoise Beetle 
 (Cdssida), the skin having being flattened and mounted 
 in Canada balsam. The spiracles are visible along the 
 sides, and at the end is seen a dark fork-like structure. 
 This is one of the peculiarities of this creature, and is 
 employed for the purpose of carrying the refuse of -its 
 food, which is always piled upon its back, and retained 
 in its place by the forked spines, aided probably by the 
 numerous smaller spines that project from the side. 
 
 Fig. 33 shows part of the stomach and gastric teeth 
 of the Grasshopper. This structure may be seen to 
 perfection in the " gizzard," as it is called, of the great 
 green Locust of England (Acrida viridissima). The 
 
136 WINGS OF INSECTS. 
 
 organ looks like a sudden swelling of the oesophagus, 
 and when slit longitudinally under water, the teeth 
 may be seen in rows set side by side, and evidently 
 having a great grinding power. Just above, fig. 27, is 
 the corresponding structure in the Hive Bee, three of 
 the teeth being shown separately at fig. 28. 
 
 WE now cast a rapid glance at the Wings of insects. 
 
 They have no analogy, except in their use, with the 
 wings of birds, as they are not modifications of existing 
 limbs, but entirely separate organs. They consist of 
 two membranes united at their edges, and traversed 
 and supported by sundry hollow branches or "ner- 
 vures," which admit air, and serve as useful guides to 
 entomologists for separating the insects into their 
 genera. Indeed, the general character of the wings 
 has long been employed as the means of dividing the 
 insect race into their different orders, as may be seen 
 in any work on entomology. The primary number of 
 wings is four, but it often happens that two are almost 
 wholly absent, or that the uppermost pair are thickened 
 into a shelly kind of substance which renders them 
 useless for flight, while in many insects, such as the 
 Ground Beetles and others, the upper wings become 
 hardened into firm coverings for the body, and the 
 lower pair are shrivelled and useless. 
 
BOOKLETS OF WINGS. 137 
 
 Fig. 22 shows two of the wings of a Humble Bee, 
 together with their nervures, and the peculiar system 
 by which the upper and lower pair are united together 
 at the will of the insect. At the upper edge of the 
 lower wing, and nearly at its extremity, may be seen 
 a row of very tiny hooks, shown on a larger scale at 
 fig. 25. These booklets hitch into the strengthened 
 membrane of the upper wing, which is seen immediately 
 above them, and so conjoin the two together. The 
 curious wing-hooks of the Aphis may be seen on fig. 24, 
 very highly magnified. 
 
 Fig. 31 is the wing of the Midge (Psychoda), that 
 odd little insect which is seen hopping and popping 
 about on the windows of outhouses and similar locali- 
 ties, and is so hard to catch. The whole wing is plen- 
 tifully covered with elongated scales, and is a most 
 lovely object under any power of the microscope. 
 These scales run along the nervures and edges of the 
 wings, and part of a nervure is shown more highly 
 magnified at fig. 32. 
 
 At fig, 23 is shown the wing of one of the hemi- 
 pterous insects, common along the banks of ditches and 
 in shady lanes, and known by the name of Cixius. It 
 is remarkable for the numerous spots which stud the 
 nervures, one being always found at each forking, and 
 +he others being very irregularly disposed. 
 
138 BALANCERS. 
 
 Fig. 30 is one of the balancers or " halteres " of the 
 House-fly. These organs are found in all the two- 
 winged insects, and are evidently modifications of the 
 second pair of wings. They are covered with little 
 vesicles, and protected at their base by scales. Some 
 writers suppose that the sense of smell resides in these 
 organs. Whatever other purpose they may serve, they 
 clearly aid in the flight, as, if the insect be deprived of 
 one or both of the balancers, it has the greatest difficulty 
 in steering itself through the air. 
 
 The wings of insects are mostly covered with hairs 
 or scales, several examples of which are given in Plate 
 VIII. Fig. 4 shows one of the scales of the Adippe or 
 Fritillary Butterfly, exhibiting the double membrane 
 part of which has been torn away and the beautiful 
 lines of dots with which it is marked. The structure 
 of the scales is further shown by a torn specimen of 
 Tiger Moth scale seen on fig. 1 6. On many scales these 
 dots assume a " watered " aspect when the focus or 
 illumination changes an example of which may be seen 
 on fig. 15, a scale of the Peacock Butterfly. 
 
 Fig. 11 is one of the ordinary scales of the Azure 
 Blue Butterfly, and fig. 10 shows one of the curious 
 " battledore " scales of the same insect, with its rows of 
 distinct dottings. Fig. 14 is one of the prettily tufted 
 scales of the Orange-tip Butterfly, and fig. 8 is the splen- 
 
SCALES OF INSECTS. 139 
 
 did branched scale of the Death's-head Moth. Fig. 19 
 shows a scale of the Sugar-runner (Lepisma saccha- 
 rind), a little silvery creature with glistening Tskin, and 
 long bristles at the head and tail, that is found running 
 about cupboards, window-sills, and similar places. It 
 is not easy to catch with the fingers, as it slips through 
 them like oil, but if the finger be afterwards examined, 
 some of the beautiful scales will be found adhering, and 
 may be placed under the microscope.- The Gnats also 
 possess very pretty scales, with the ribs projecting 
 beyond the membrane. 
 
 Fig. 21 is a scale from the common Spring-tail 
 (Podura plumbea), a little creature which is found plen- 
 tifully in cellars and other damp places, skipping about 
 with great activity. Some flour scattered on a piece of 
 paper is a sure trap for these little beings. Fig. 3 is 
 one of the scales taken from the back of the celebrated 
 Diamond Beetle, showing the cause of the magnificent 
 gem-like aspect of that insect. We have in England 
 many beetles of the same family the Weevils which, 
 although much smaller, are quite as splendid when ex- 
 hibited under a microscope by reflected light. The wing- 
 case or " elytron " of a little green weevil, very common 
 in the hedges, may be seen on Plate XII. fig. 10. 
 
 The reader will observe that all these scales are 
 furnished with little root-like appendages, by means of 
 
140 EGGS OF INSECTS. 
 
 which they are affixed to the insect. Fig. 13 shows a 
 portion of the wing of the Azure Blue Butterfly, from 
 which nearly all the scales have been removed, for the 
 purpose of exhibiting the pits or depressions in which 
 they had formerly been fastened, and one or two of the 
 scales are left still adherent to their places. The scales 
 are arranged in equal rows like the slates of a housetop, 
 as may be seen on fig. 1 8, which represents part of the 
 same wing, to show the scales overlapping each other, 
 and the elegant form which they take near the edges of 
 the wing, so as to form a delicate fringe. The long 
 hair-like down which covers the legs and bodies of the 
 moths and butterflies (which are called Lepid6ptera 
 or scale-winged insects in consequence of this pecu- 
 liarity), is seen under the microscope to be composed 
 of scales very much elongated, as is shown in fig. 17, a 
 portion taken from the leg of a Tiger Moth. 
 
 THE Eggs of insects are all very beautiful, and three 
 of the most curious forms are given on Plate VIII. 
 
 Fig. 2 is the empty egg of the Gad-fly, as it appears 
 fastened to a hair of a horse. Fig. 5 represents the 
 pretty ribbed egg of the common Tortoiseshell Butter- 
 fly; and fig. 7 is the very beautiful egg of the very 
 horrid Bed-bug, worthy of notice on account of the 
 curious lid with which its extremity is closed, and by 
 
STINGS AND SAWS. 141 
 
 means of which the young larva creeps out as soon as it 
 is hatched. 
 
 Fig. 9 shows the penetrating portions of the Sting 
 of the Wasp. The two barbed stings, which seem to 
 be the minute prototypes of the many-barbed spears 
 of the South Sea Islanders, are seen lying one at each 
 side of their sheath, and a single barb is drawn a 
 little to the left on a very much larger scale. It is 
 by reason of these barbs that the sting is always left 
 adhering to the wound, and is generally drawn wholly 
 out of the insect, causing its death in a short while. 
 
 The sting is only found in female insects, and is sup- 
 posed to be analogous to the " ovipositor " of other 
 insects, i.e. the instrument by which the eggs are depo- 
 sited in their places. Fig. 20 shows the curious egg- 
 placing apparatus of one of the Saw-flies. The backs 
 of these "saws" work in grooves, and they work alter- 
 nately, so that the fly takes but a very short time in 
 cutting a slit in the young bark of a tender shoot, and 
 laying her eggs in the slit. When she has completed 
 one of these channels, she sets to work upon another, 
 and in the early spring the young branches of the goose- 
 berry bushes may be seen plentifully covered with 
 these grooves and the eggs. When hatched, from the 
 eggs issue black caterpillar-like grubs, which devastate 
 the bushes sadly, and in process of time turn into 
 
142 HAIRS OF ANIMALS. 
 
 blackish flies, which are seen hovering in numbers over 
 the gooseberries, and may be killed by thousands. 
 
 THE scales and hairs of other animals deserve great 
 attention. Fig. 23 is a single hair of the human beard, 
 as it often appears when tied in a knot by Queen 
 Mab and her fairies, according to Mercutio. Fig. 22 
 is a portion of the same hair as it appears when split- 
 ting at its extremity. The structure of the hair is not, 
 however, so well seen in this object as in that repre- 
 sented on fig. 24, which is a beautiful example of white 
 human hair, that once adorned the head of the victor 
 of Waterloo. It formed one of a tiny lock given to 
 me by a friend, and is so admirable an example of 
 human hair, that I forthwith mounted it for the micro- 
 scope. In this hair the marrow-cells may be seen 
 extending down its centre, and the peculiar roughened 
 surface produced by the flattened cells which are 
 arranged around its circumference are also seen. By 
 steeping in caustic potash, these scales can be separated, 
 but generally they lie along the hair in such a manner 
 that if the hair be drawn through the fingers from base 
 to point, their projecting ends permit it to pass freely; 
 but if it be drawn in the reverse direction, they cause 
 it to feel very harsh to the touch. 
 
 In the Sheep's Wool, fig. 30, this structure is much 
 
HAIRS AND FIBRES. 143 
 
 more developed, and gives to the fibres the " felting " 
 power that causes them to interlace so firmly with 
 each other, and enables cloth when really made of 
 wool to be cut without unravelling. Fig. 37 is the 
 smooth hair of the Badger ; and fig. 34 is the curious 
 hair of the Red Deer, which looks as if it had been 
 covered with a delicate net. 
 
 Fig. 28 is the soft, grey, wool-like hair of the Rat; 
 and fig. 29 is one of the larger hairs that protrude so 
 plentifully, and form the glistening brown coat of that 
 animal. Fig. 38 is the curiously knobbed hair of the 
 Long-eared Bat, the knobs being formed of protuberant 
 scales that can easily be scraped off. Fig. 31 shows a 
 hair of the common Mole ; and fig. 32 is one of the 
 long hairs of the Rabbit. Fig. 27 is a fiat hair of the 
 Dormouse, slightly twisted, the difference in the breadth 
 showing where the twist has taken place. Fig. 26 
 is one of the very long hairs that so thickly clothe the 
 Tiger Moth caterpillar; and fig. 25 is a beautifully 
 branched hair taken from the common Humble Bee. 
 
 The four fibres mostly used in the manufacture of 
 apparel are : Wool, fig. 30, which has already been 
 described ; Linen, fig. 39 ; Cotton, fig. 40 ; and Silk, 
 fig. 41. The structure of each is very well marked 
 and easily made out with the microscope ; so that an 
 adulterated article can readily be detected by a practised 
 
144 SCALES OF FISH. 
 
 eye. Cotton is mostly used in adulterations of silk and 
 linen fabrics, and may at once be detected by its flat 
 twisted fibre. Silk is always composed of two parallel 
 threads, each proceeding from one of the spinnerets of 
 the caterpillar, and it may be here remarked that if 
 these threads are not quite parallel the silk is of bad 
 quality. Silken fibre is always when new covered with 
 a kind of varnish, usually of a bright orange colour, 
 which gives the undressed " floss " silk its peculiar hue, 
 but which is soluble and easily washed away in the 
 course of manufacture. 
 
 Figs. 35 and 36 are the small and large hairs of that 
 magnificent creature, the Sea Mouse (Aphrodite aculedta), 
 whose covering, although it lies in the mud, glows with 
 every hue of the rainbow, and in a brilliant light is 
 almost painfully dazzling to the eye. 
 
 THE scales of some of the Fish are shown on Plate 
 VIII. in order to exhibit their mode of growth by 
 successive layers. The scales are always enveloped in 
 membranous sacs, and in some cases, as in the Eel, 
 they do not project beyond the surface, and require 
 some little observation to detect them. A scale of an 
 Eel is shown on Plate XI. fig. 15, and is a magnificent 
 subject under polarized light. Fig. 33 is a scale of 
 the Greenbone Pike ; and figs. 42 and 43 are scales of 
 
FEATHERS. 145 
 
 the Perch, showing the roots by which they are held 
 in their places. The Roach. Dace, Bleak, and many 
 other similar fish have some beautiful silvery crystals 
 on the under surface of the scales, which were greatly 
 used in the manufacture of artificial pearls, glass 
 beads being thinly coated in the interior with the 
 glittering substance, and then filled in with wax. A 
 piece of Sole-skin, when preserved in Canada balsam 
 and placed under the microscope, is a very beautiful 
 object. 
 
 More examples of hairs, and other processes from 
 the skin, together with the structure of the Skin itself, 
 of Bone, of Blood, and the mode in which it circulates, 
 are given on Plate X. 
 
 In all important points of their structure, the Feathers 
 of birds are similar to the hairs of animals, and are 
 developed in a similar manner. They are all composed 
 of a quill portion, in which the pith is contained, and of 
 a shaft, which carries the vane, together with its barbs. 
 The form of each of these portions is greatly modified 
 even in different parts of the same bird, and the same 
 feather has almost always two kinds of barbs ; one 
 close and firm, and the other loose, floating, and downy. 
 If a small feather be plucked from the breast or back 
 of a sparrow or any other small bird, the upper part of 
 the feather is seen to be close and firm, while the lower 
 
 L 
 
146 SPINE OF HEDGEHOG. 
 
 is loose and downy, the upper part being evidently 
 intended to lie closely on the body and keep out the 
 wet, while the lower portion affords a soft and warm 
 protection to the skin. . 
 
 Fig. 12, Plate X., shows the feather of a Peacock, 
 wherein the barbs are very slightly fringed and lie 
 quite loosely by each other's side. Fig. 18 is part of 
 the same structure, in a Duck's feather, wherein are 
 seen the curious hooks which enable each vane to take 
 a firm hold of its neighbour, and so to render the 
 whole feather firm, compact, and capable of repelling 
 water. The reader will not fail to notice the remark- 
 able analogy between these hooks and those which 
 connect the wings of the bee. 
 
 Fig. 17 is a part of the shaft of a young feather 
 taken from the Canary, and given for the purpose 
 of showing the form of the cells of which the pith 
 is composed. Fig. 20 is part of the down from a 
 Sparrow's feather, showing its peculiar structure ; and 
 fig. 21 is a portion of one of the long drooping feathers 
 of the Cock's tail. 
 
 Fig. 13 exhibits a transverse section of one of the 
 large hairs or spines from the Hedgehog, and shows 
 the disposition of the firm, horn-like exterior, and the 
 arrangement of the cells. Sections of various kinds 
 of hair are interesting objects, and are easily made by 
 
SKIN AND SWEAT DUCTS. 147 
 
 tying a bundle of them ' together, soaking them in 
 glue, letting them harden, and then cutting thin slices 
 with a razor. A little water will dissolve the glue, and 
 the sections of hair will be well shown. Unless some 
 such precaution be taken, the elasticity of the hair will 
 cause the tiny sections to fly in all directions, and there 
 will be no hope of recovering them. 
 
 Several examples of the Skin are also given. Fig. 27 
 is 'a section through the skin of the human finger, 
 including one of the little ridges which are seen upon 
 the extremity of every finger, and half of two others. 
 The cuticle, epidermis, or scarf-skin, as it is indifferently 
 termed, is formed by flattened cells or scales, is conse- 
 quently very thin, and is shown by the dark outline of 
 the top. The true skin or " cutis " is fibrous in structure, 
 and lies immediately beneath, the two together con- 
 stituting the skin, properly so called. Beneath lies a 
 layer of tissue filled with fatty globules, and containing 
 the glands by which the perspiration is secreted. 
 
 One of the tubes or channels by which these glands 
 are enabled to pour their contents to the outside of the 
 body, and if they be kept perfectly clean, to disperse 
 them into the air, is seen running up the centre of the 
 figure, and terminating in a cup-shaped orifice on the 
 surface of the cuticle. On the palm of the hand very 
 nearly three thousand of these ducts lie within the 
 L 2 
 
148 EPITHELIUM. 
 
 compass of a square inch, and more than a thousand 
 in every square inch of the arm and other portions of 
 the body, so that the multitude of these valuable 
 organs may be well estimated, together with the 
 absolute necessity for keeping the skin perfectly clean 
 in order to enjoy full health. 
 
 Fig. 1 shows a specimen of epidermis taken from 
 the skin of a Frog, exhibiting the flattened cells 
 which constitute that structure, and the oval or slightly 
 elongated nuclei, of which each cell has one. In fig. 32, 
 being a portion of a Bat's wing, the arrangement of 
 the pigment is remarkably pretty. Immediately 
 above, at fig. 31, is some of the pigment taken from 
 the back of the human eyeball, which gives to the 
 pupil that deep black aspect which it presents. The 
 shape of the pigment particles is well shown. Fig. 33 
 shows the pigment in the shell of the Prawn. 
 
 ON various parts of animal structures, such as the 
 lining of internal cavities, the interior of the mouth, 
 and other similar portions of the body, the cells are 
 developed into a peculiar form which is called " Epi- 
 th61ium," and which supplies the place of the epidermis 
 of the exterior surface of the body. The cells which 
 form this substance are of different shapes, according 
 to their locality. On the tongue, for example (for which 
 

 
BONE. 149 
 
 see fig. 11), they are flattened, and exhibit their nucleus, 
 in which the nucleolus, or something which goes by 
 that name, may he discovered with a little care. Cells 
 of this kind Lre sometimes rounded, as in the case just 
 mentioned, or angular, and in either case they are 
 termed " pavement " or " tesselated " epithelium. Some- 
 times they are like a number of cylinders, cones, or 
 pyramids, ranged closely together, and are then called 
 cylinder epithelium. Sometimes the free ends of 
 cylinder epithelium are furnished with a number of 
 vibrating filaments or cilia, and in this case the 
 structure is called " ciliated " epithelium. Cylinder 
 epithelium may be found in the ducts of the glands 
 which open into the intestines, as well as in the glands 
 that secrete tears ; and ciliated epithelium is seen 
 largely in the windpipe, the interior of the nose, &c. 
 A specimen taken from the nose is seen at fig. 15. 
 
 BONE in its various stages is figured on Plate X. 
 
 Fig. 9 is a good example of human bone, and is a 
 thin transverse section taken from the thigh. When 
 cut asunder, bone exhibits a whitish structure filled 
 with little dottings that become more numerous towards 
 the centre, and are almost invisible towards the circum- 
 ference. In the centre of the bone there is a cavity, 
 which contains marrow in the mammalia, and air in 
 
150 BONE AND CARTILAGE. 
 
 the birds. When placed under a microscope, the bone 
 presents the appearance shown in the illustration. 
 
 The large aperture in the centre is one of the innu- 
 merable tubes that run through the bone, and that serve 
 to allow a passage to the vessels which convey blood 
 from one part of the bone to another. They are tech- 
 nically called Haversian canals, and if a longitudinal 
 section be made, they will be found running tolerably 
 parallel, and communicating freely with each other. 
 Around each Haversian canal may be seen a number of 
 little black spots with lines radiating in all directions, 
 and looking something like flattened insects. These are 
 termed bone-cells or "lacunae," and the little black 
 lines are called " canaliculi." When viewed by trans- 
 mitted light, the lacunas, together with the canaliculi, 
 are black; but when the mirror is turned aside, and 
 light thrown on the object by the condenser, the 
 Haversian canals become black, and the lacunae are 
 white. 
 
 As these canaliculi exist equally in every direction, 
 it is impossible to make a section of bone without 
 cutting myriads of these across; and when a high 
 power is employed, they look like little dots scattered 
 over the surface. A very pretty object can be made 
 of the bone taken from a young animal which has been 
 fed with madder, as the colour gets into the bone and 
 
ANIMAL CELLS. 151 
 
 settles chiefly round the Haversian canal. A young 
 pig is a very good subject, so is a rabbit. 
 
 Fig. 16 is a similar section cut from the leg-bone of 
 an Ostrich. 
 
 The development of bone is beautifully shown in 
 fig. 30, a delicate slice taken from a Pig's rib. Above 
 may be seen the gristle or cartilage, with the numerous 
 rows of cells; below is the formed bone, with one of 
 the Haversian canals and its contents ; while between 
 the two may *be seen the cartilage-cells gathering 
 together and arranging themselves into form. The 
 cartilage-cells are well shown in fig. 28, which is a 
 portion of the cup which had contained the eye of a 
 Haddock. 
 
 The horn-like substances at the end of our fingers, 
 which we popularly call our Nails, are composed of 
 innumerable flattened cells. These cells are generally 
 so fused together as to be quite indistinguishable even 
 with a microscope, but can be rendered visible by soak- 
 ing a section of nail in liquor potassao, which causes the 
 cells to swell up and resume to a degree their original 
 rounded form. 
 
 It is worthy of remark that the animal form is built 
 up of cells, as is the case with the vegetables, although 
 the cells are not so variable in shape. They generally 
 may be found to contain nuclei well marked, two or 
 
152 TfiETfl. 
 
 more being often found within a single cell, and in 
 many cases the tiny nuclebli are also visible. Good 
 examples of these cells may be obtained from the yolk 
 of an egg, and by careful management they may be 
 traced throughout every part of the animal form. The 
 aid of chemistry is often needed in order to force the 
 cells to exhibit themselves in their true forms. 
 
 The Teeth have many of the constituents of bone, 
 and in some of their parts are made precisely after the 
 same fashion. When cut, the teeth are" seen to consist 
 of a hard substance, called Enamel, which coats their 
 upper surfaces, of ivory within the enamel, and of 
 "cement," which surrounds the fangs. In fig. 26, 
 Plate X., which is a longitudinal section of the human 
 "eye" tooth, the enamel is seen above, the ivory occu- 
 pying the greater part of the tooth, and the cement at 
 the bottom. In the centre of each tooth there is a 
 cavity, which is plentifully filled with a pulpy substance 
 from which the tooth is formed. A transverse section 
 of the same tooth is seen at fig. 25. 
 
 The enamel is made of little elongated prisms, all 
 pointing to the centre of the tooth. When viewed 
 transversely, their ends are of a somewhat hexagonal 
 shape, something like an irregular honeycomb. The 
 Ivory is composed of a substance pierced with myriads 
 of minute tubes, which give out branches that commu- 
 
ELASTIC LIGAMENT. 153 
 
 nicate freely with each other. They require a rather high 
 power say 300 diameters to show them properly. 
 The cement is found at the root of the fangs, and is 
 best shown in the tooth of an aged individual, when it 
 assumes very clearly the character of bone. 
 
 Sections may be made by sawing a slice in the 
 required direction, polishing one side, and cementing it 
 with old Canada balsam to a slide. It may then be filed 
 down to nearly the required thinness, finished by care- 
 fully rubbing with a hone, and polished with buff 
 leather. Canada balsam may then be dropped upon it, 
 and a glass cover pressed firmly down. Sections of 
 young bone form magnificent objects for the polariser. 
 
 Fig. 29 is a section cut from one of the palate teeth 
 of the Ray (Myliobates). 
 
 A rather important element in the structure of 
 animals is the " elastic ligament " which is found in the 
 back of the neck, and other parts of the body, espe- 
 cially about the spine. It is made of a vast number 
 of fibres of variable shape and length, arranged gene- 
 rally in bundles, and remarkable for containing very few 
 vessels, and no nerves at all. At fig. 14 may be seen 
 an example of elastic ligament, popularly called " pax- 
 wax/' taken from the neck of a sheep. 
 
 The white fibrous tissue by which all the parts of 
 the body are bound together is seen at fig. 10; and at 
 
154 MUSCLES AND NERVES. 
 
 fig. 1 1 is a beautiful example of " ultimate " fibrous 
 tissue taken from the crystalline lens of a Sturgeon's 
 eye. 
 
 The muscles of animals are composed of two kinds 
 of fibre, the one termed the striped, and the other the 
 unstriped. Of these, the latter belongs to organs which 
 work without the will, such as the stomach, &c., while 
 the former belongs to those portions of the body which 
 are subject to voluntary motion, such as the arm and 
 the leg. The unstriped muscle is very simple, consist- 
 ing merely of long simple fibres; but the striped or 
 voluntary muscle is of more complex construction. 
 Every voluntary muscle consists of myriads of tiny 
 fibres, bound together in little bundles, enveloped in a 
 kind of sheath. Fig. 24 is an example of this muscu- 
 lar fibre, taken from beef. When soaked in spirits, it 
 often splits into a number of discs, the edges of which 
 are marked by the transverse lines. 
 
 A fibre of Nerve is drawn at fig. 23, and is given for 
 the purpose of showing the manner in which the nerve 
 is contained in and protected by its sheath, just like a 
 telegraph-wire in its coverings. Just above is a trans- 
 verse section of the same fibre, showing the same 
 arrangement from another point of view, and also 
 illustrating the curious phenomenon, that when nerve- 
 fibres are treated with carmine, the centre takes up the 
 
 
BLOOD AND ITS STRUCTURE. 155 
 
 colouring matter, while the sheath remains white as 
 before. Dissection of nerves is a tedious and difficult 
 subject, and requires the aid of good books and instru- 
 ments for its successful achievement. 
 
 The Blood of animals is analogous in its office to the 
 sap of plants, but differs greatly from it under the 
 microscope. In sap there seem to be no microscopic 
 characters, except that when a branch is cut, as in the 
 vine, the flowing sap may contain certain substances 
 formed in the wounded cells, such as chlorophyll, starch, 
 and raphides ; but the blood is known to be an exceed- 
 ingly complex substance both in a microscopic and 
 chemical point of view. When a little recent blood is 
 placed under the microscope, it is seen to consist of a 
 colourless fluid filled with numerous little bodies, com- 
 monly called " blood-globules," varying very greatly in 
 size and shape, according to the animal from which 
 they were taken. Those of the reptiles are very large, 
 as may be seen at fig. 4, Plate X., which represents a 
 blood corpuscle of the Proteus. In this curious reptile 
 the globules are so large that they may be distinguished 
 during its life by means of a common pocket-lens. 
 
 In the vertebrated animals these corpuscules are red, 
 and give to the blood its peculiar tint. They are 
 accompanied by certain colourless corpuscules, spherical 
 in form, which are sometimes, as in man, larger than 
 
156 CHARACTERS OF THE BLOOD. 
 
 the red globules, and in others, as in the Siren and the 
 Newt, considerably smaller. The general view of these 
 red corpuscules has sufficient character to enable the 
 practised observer to name the class of animal from 
 which it was taken, and in some cases they are so well 
 marked that even the genus can be ascertained with 
 tolerable certainty. In point of size, the reptiles have 
 the largest, and the mammalia the smallest, those of 
 the Siren and the Goat being, perhaps, the most de- 
 cidedly opposed to each other in this respect. 
 
 In shape, those of the Mammalia are circular discs, 
 mostly with a hollowed centre ; those of the Birds are 
 more or less oval and convex ; those of the Hep tiles are 
 decidedly oval, very thin, and mostly have the nucleus 
 projecting; and those of the Fishes are oval and mostly 
 convex. During the process of coagulation, the blood 
 corpuscules run together into a series of rows, just as if 
 a heap of pence had been piled on each other, and then 
 pushed down, so that each penny overlaps its next 
 neighbour. 
 
 These objects are illustrated by six examples on 
 Plate X. Fig. 2 is Human blood, showing one of the white 
 corpuscules. Fig. 3 is the blood of the Pigeon ; fig. 4, of 
 the Proteus anguinus ; fig. 5, of the Tortoise ; fig. 6, of 
 the Frog, showing the projecting nucleus; and fig. 7, 
 of the Roach. The blood possesses many curious 
 
FROG PLATE. 157 
 
 properties, which cannot be described in these few and 
 simple pages. 
 
 In the centre of Plate X. is a large circular figure 
 representing the membrane of a Frog's foot as seen 
 through the microscope, and exhibiting the circulation 
 of the blood. The mode of arranging the foot so as to 
 exhibit the object without hurting the frog is simple 
 enough. 
 
 Take an oblong slip of wood my own was made in 
 five minutes out of the top of a cigar-box bore a 
 hole about an inch in diameter near one end, and cut a 
 number of little slits all round the edge of the wooden 
 slip. Then get a small linen bag, put the frog into 
 it, and dip him into water to keep him comfortable. 
 When he is wanted, pull one of his hind feet out of 
 the bag, draw the neck tight enough to prevent him 
 from pulling his foot back again, but not sufficiently 
 tight to stop the circulation. Have a tape fastened to 
 the end of the bag, and tie it down to the wooden slide. 
 
 Then fasten a thread to each of his toes, bring the 
 foot well over the centre of the hole, stretch the toes 
 well apart, and keep them in their places by hitching 
 the threads into the notches on the edge of the wooden 
 strip. Push a glass slide carefully between the foot 
 and the wood, so as to let the membrane rest upon the 
 glass, and be careful to keep it well wetted. If the 
 
158 CIRCULATION". 
 
 frog kicks, as he will most likely do, pass a thin tape 
 over the middle of the leg, and tie it down gently to 
 the slide. 
 
 Bring the glass into focus, and the foot will present 
 the appearance so well depicted in the engraving. The 
 veins and arteries are seen spreading over the whole of 
 the membrane, the larger arteries being often accom- 
 panied by a nerve, as seen in the illustration. Through 
 ^ all these channels the blood continually pours with a 
 rather irregular motion, caused most probably by the 
 peculiar position of the reptile. It is a most wonderful 
 sight, of which the observer is never tired, arid which 
 seems almost more interesting every time that it is 
 beheld. 
 
 The corpuscules go pushing and jostling one another 
 in the oddest fashion, just like a British crowd entering 
 an exhibition, each one seeming to be elbowing its way 
 to the best place. To see them turning the corners is 
 very amusing, for they always seem as if they never 
 could get round the smaller vessels, and yet invariably 
 accomplish the task with perfect ease, turning about 
 and steering themselves as if possessed of volition, and 
 insinuating their ends when they could not pass cross- 
 wise. 
 
 By putting various substances, such as spirits or salt, 
 upon the foot, the rapidity of the circulation can be 
 
IN A FROG'S FOOT OR FISH'S TAIL. 159 
 
 greatly increased or reduced at will, or even stopped 
 altogether for a while, and the phenomenon of inflam- 
 mation and its gradual natural cure be beautifully 
 illustrated. The numerous black spots upon the sur- 
 face are caused by pigment. 
 
 The tails of young fish also afford excellent objects 
 under the microscope, as the circulation can be seen 
 nearly as well as in the Frog's foot. The gills of Tad- 
 poles can also be arranged upon the stage with a little 
 care, and the same organs in the young of the common 
 Newt will also exhibit the circulation in a favourable 
 manner. The Frog, however, is perhaps the best, as it 
 can be arranged on the " frog-plate " without difficulty, 
 and the creature may be kept for months by placing it 
 in a cool, damp spot, and feeding it with flies, little 
 slugs, and similar creatures. 
 
160 
 
 CHAPTER VII. 
 
 INFUSORIA ROTIFERS POND HUNTING SPONGES NOCTILUCA 
 SEA ANEMONES JELLY FISH FORAMINIFERA ZOOPHYTES 
 ENTOMOSTRACA LARVA OF CRAB STRUCTURE OF SHELL 
 CILIA OF MUSSEL STAR-FISHES AND ECHINI PEDICILLARIA 
 CORALLINE CAPILLARY VESSELS INJECTIONS COAL GOLD- 
 DUST AND COPPER POLARIZED LIGHT. 
 
 TURNING back for a while to Plate IX. we come 
 upon a series of objects which have long been termed 
 Infusoria, because they are found in water in which 
 vegetable or animal substances have been steeped. 
 They get into almost every drop of water in which 
 such substances have lain, and may be found even in 
 the mud on the road or the roof-pipes of houses. 
 Many of these curious beings are tolerably familiar to 
 the public, through the medium of the oxy-hydrogen 
 microscope so popular at exhibitions, and are generally 
 supposed to be inhabitants of every drop of water 
 which we drink. This, however, is not the case, as the 
 water is always prepared for the purpose ; hay, leaves, 
 or similar substances being steeped in it for some 
 weeks, and the turbid scrapings placed under the micro- 
 
 
INFUSORIA. 161 
 
 scope to discompose the public mind. The whole 
 history of these creatures is very obscure, and seems 
 unlikely to be satisfactorily settled for the present. 
 Suffice it to say that they may be found in almost 
 every localityin every climate, being capable of with- 
 standing cold far below zero and heat far above the 
 boiling point, and may be dried over and over again, 
 without seeming to care anything about the matter. 
 Their increase is wonderfully rapid, taking place by 
 subdivision, and thereby spreading the minute organisms 
 throughout a large mass of water in an incredibly short 
 space of time. So rapid is the process, that it may 
 even be noticed under the microscope, and is remark- 
 ably interesting. 
 
 If a little hay or leaves be put into water, and 
 suffered to remain in the open air for a week or two, 
 a kind of deposit will collect round the decaying 
 vegetation, and when submitted to the microscope is 
 seen to contain a vast number of these minute but 
 interesting beings. Many persons are fond of making 
 skeleton plants by steeping them in water for a long 
 time. The vessels in which this operation is performed 
 are found to be extremely fertile in these curious little 
 infusoria. 
 
 When some of the muddier portion of the water is 
 placed under the microscope, it will be seen to be 
 
 M 
 
162 PARAMCECIUM. 
 
 absolutely crowded with moving creatures, running 
 restlessly in all directions, like Yathek and his com- 
 panions in the Hall of Eblis, and in a similar manner 
 avoiding each other, as if repelled by some innate 
 force. On a closer examination, this moving crowd 
 gradually resolves itself into variously shaped forms, 
 among which one of the largest, and strongest, and 
 swiftest is that which is represented in fig. 5, Plate IX., 
 and is known by the name of Paramoecium. 
 
 It is one of a large family of Infusoria, the genera 
 of which are reckoned at twelve in number. In size 
 it is so large, that when the vessel of water is held 
 between the eye and the light, it may be seen as a very 
 minute white speck moving through the water. Its 
 body is covered with vibrating cilia, by means of which 
 it whirls itself through the water, and drives its food 
 within reach of its mouth. The mode of action may 
 be readily comprehended by putting a little carmine 
 into the water, when the crimson particles will be seen 
 hurled in regular currents by the cilia, and after awhile 
 many will be distinguished within the transparent 
 body. At each end of the Paramoecium there is a 
 curious star-shaped, contractile vesicle. The cilia are 
 arranged in regular rows. Three of the dart-like 
 weapons with which it is armed are seen just below 
 the figure. 
 
AMOEBA. 163 
 
 Perhaps the lowest form of animal life is to be found 
 in another of these Infusoria, the Amoeba, which is 
 represented at fig. 1. 
 
 This wonderful creature is remarkable for having no 
 particular shape, altering its form momentarily, and 
 moving by means of this curious mode of progression. 
 At first it mostly looks like a little rounded semi- 
 transparent mass, but in a short time it begins to push 
 out one part of its body into a projection of some 
 length, which gradually fixes itself to some convenient 
 object, and by contraction draws the body after it. In 
 fig. 1 three forms of the same creature are shown, one 
 of which is remarkable for having included a large 
 diatom in its structure. 
 
 The mode by which this creature feeds is the simplest 
 imaginable. Any object which may serve as food, such 
 as a diatom, a desmid, or another infusorial, comes in 
 contact with the surface of its body, and is there held. 
 Presently, that portion of the body whereon the captured 
 organism lies begins to recede and forms a cavity, into 
 which it is pressed. This cavity answers the purpose 
 of a stomach, and the indigestible portions are either 
 returned by the same way, or squeezed through some 
 other portion of the animal. Such inclosed organisms 
 may be seen in the figure. 
 
 At fig. 2 may be seen another curious creature named 
 M 2 
 
164 SUN ANIMALCULE. 
 
 the Arcella, which is in fact little more than an Amoeba 
 with a shell, the soft body altering its shape in pre 
 cisely the same manner. 
 
 A very curious Infusorial is shown at fig, 3. This is 
 the Sun animalcule (Actinophrys Sol), remarkable foi 
 the long tentacles with which its body is surrounded. 
 The nourishment of this creature is managed after the 
 same manner as has already been mentioned when 
 treating of the Amoaba. The organisms which serve 
 for its food are captured by one of the tentacles, which 
 immediately begins to contract. Those surrounding it 
 give their aid by bending towards it, and by their 
 united force the victim is gradually pressed into the 
 body, where it is digested. 
 
 Fig. 6 is given in order to show the process of sub- 
 division as it takes place in the Infusoria. The species 
 figured is the Chilodon, another flattened creature 
 covered with cilia, with teeth arranged in the form of 
 a tube, and with the fore part of the so-called head 
 having a kind of membranous lip. 
 
 These creatures, together with many minute inha- 
 bitants of the waters, are of incalculable use in devour- 
 ing the decaying substances that would otherwise breed 
 pestilence, and converting them into their own living 
 persons. 
 
 Figs. 7 and 10 represent two examples of the singular 
 
XII. 
 
ROTIFERS OR WHEEL ANIMALCULES. 165 
 
 beings called Rotifers, on account of the wheel-like 
 apparatus which they bear. Upon the front of the 
 body or head is a retractile disc, whose edges are covered 
 with cilia, which, by bending in regular succession, look 
 exactly as if they were wheels running round at a great 
 rate. A similar phenomenon may be seen in the corn- 
 fields, when the wind forces them to bend, and produces 
 a succession of waves that seem to roll over the field. 
 These cilia are their chief modes of progression ; but 
 in many cases they get along rather fast by attaching 
 their tails and heads alternately to the substances on 
 which they move, after the well-known fashion of the 
 leech, to which they then bear no small resemblance 
 Fig. 10 represents the commonest species of rotifer, 
 Rotifer vulgdris, in which this mode of progression 
 may be seen. 
 
 They are furnished with a well-defined mouth and 
 digestive organs, and their teeth, a pair of which may 
 be seen in fig. 11, are very powerful. 
 
 Some species of Rotifer, such as Melicerta, fig. 7, are 
 inclosed in a tube. In some cases, as in the present, 
 the tube is opaque ; but in many it is beautifully trans- 
 parent, and permits the inclosed creature to be seen 
 through its substance. 
 
 I would that rapidly narrowing space did not compel 
 me to give such brief notice of these most interesting 
 
166 POND-HUNTING. 
 
 creatures. They may, however, be readily obtained in 
 almost any pond, provided the water be not putrid, and 
 are so large that their movements may be watched with 
 a rather low power. There are very many species, but 
 they may be distinguished from the other inhabitants 
 of the waters by the wheel-like processes from which 
 they derive their name. Sometimes the wheel-disc is 
 withdrawn within the body ; but if the observer wait 
 for a little while, he is sure to see the disc protruded 
 and the wheels run their merry course. 
 
 The mode of obtaining these tiny creatures is suffi- 
 ciently simple. 
 
 Get a small, rather wide-mouthed phial, and with the 
 piece of string which every sensible man always has in 
 his pocket, lash the bottle by the neck across the end 
 of a walking-stick. Look out for the best hunting- 
 grounds in ponds, rivulets, &c., an accomplishment in 
 which practice soon makes perfect ; push the inverted 
 bottle among the flocculent greenage or the decaying 
 leaves, and after poking it well about, turn the bottle 
 suddenly over, when the water will rush rapidly in, 
 carrying with it myriads of minute organisms. After 
 a little experience in this kind of fishing, it soon 
 becomes easy to capture any creature that may be 
 seen in the water, by placing the inverted bottle deli- 
 cately near the intended victim, and then quietly 
 
CONVEYANCE OF SPECIMENS. 167 
 
 turning it over without alarming the easily frightened 
 creature. 
 
 When the bottle is filled, the contents should be 
 poured into another wide-mouthed bottle, and the 
 process repeated until a sufficient amount of living 
 organisms has been obtained. The bottle should 
 always be labelled with the particular place, pond, or 
 stream whence the water was obtained ; and it is 
 always well to add the date. It will be found advisable 
 to have a number of wide-mouthed bottles always 
 ready, which can be carried 
 in a basket or box fitted up 
 for the purpose by means 
 of wooden partitions, or 
 even by strings crossing 
 each other at proper in- 
 tervals. One reason for this 
 precaution is the power of 
 identifying the exact locality in which any rare or 
 curious creatures may be found ; and another reason is, 
 that the inhabitants of different ponds or puddles are 
 apt to wage deadly war if put into the same bottle. A 
 drawing of a case fitted up with bottles is here intro- 
 duced, more for the purpose of giving the reader a model 
 on which to make a hunting-case for himself, than to 
 recommend him to purchase or order it from a carpenter. 
 
168 PERFORATED CORKS. 
 
 The air must always be admitted freely into the 
 bottles, or the creatures will soon die. But as the 
 conveyance of uncorked wide-mouthed bottles half full 
 of water is exceedingly inconvenient, it is needful to 
 fill up each bottle in such a manner that the air can 
 be freely admitted, while the water will not run out. 
 
 A very simple contrivance is to close the mouths of 
 the bottles with corks, to bore a hole through the 
 centre of each cork, and to pass a quill through it, 
 projecting about half an inch through the cork within 
 the bottle, and cut off level above. Even if the bottle 
 should be turned upside down by any mischance, 
 scarcely a drop of water will escape ; while the air is 
 admitted nearly as freely as if the mouth of the bottle 
 were open. 
 
 One bottle should be supplied with some of the mud 
 taken from the bottom of the pool or puddle, as it is 
 sure to contain many interesting objects, and is gene- 
 rally a rich preserve of the flinty skeletons of these 
 little inhabitants of the waters. 
 
 They are easily separated from the other constituents 
 of the mud, by putting a little of the mud into the 
 bottom of a tall test-tube, pouring some nitric acid 
 upon it, and boiling it gently over the flame of the spirit- 
 lamp. Very great care is needed in this operation, as 
 the liquid is apt to rise suddenly and boil over ; and 
 
PREPARING SKELETONS OF DIATOMS. 169 
 
 the fumes which arise are always copious and very 
 deleterious, so that the .boiling should always be done 
 in the open air, or at all events in some place where 
 the fumes can be carried away as fast as they are 
 generated. 
 
 After it has boiled for some little time, and got cool, 
 half fill the tube with distilled water, shake it up well, 
 and set the tube upright so as to let the solid particles 
 sink to the bottom. When it has thoroughly settled, 
 which will not be for some hours, remove the clear 
 liquid by means of a syphon a wet skein of cotton 
 thread hung over the edge of the tube will do very 
 well pour in some fresh nitric acid, and boil it again. 
 Repeat this process three or four times, and then wash 
 the residue very thoroughly in distilled water, always 
 allowing the solid matter to settle, and removing the 
 liquid with a siphon ; and when the acid has been 
 entirely washed away, spread some of the residue upon 
 a clean slide, and examine it under the microscope. 
 The field of the instrument will then be filled with the 
 lovelv flint scaffolding upon which the living organisms 
 of these minute creations are supported ; and when 
 some peculiarly good specimens are found, they should 
 be preserved as permanent objects by dropping a little 
 Canada balsam upon them and mounting them after 
 the manner already described. 
 
170 NETS. 
 
 There is a considerable amount of amusement to be 
 got out of this kind of fishing, as it is always a sort of 
 lottery, in which the blanks are none, and the prizes 
 many. 
 
 For the capture of the larger creatures, such as are 
 readily visible to the naked eye, and swim with much 
 velocity, a net is needful. This is readily made by 
 twisting a piece of brass or copper wire into a ring, 
 and sewing a piece of very fine net over it so as to give 
 it a hollow about as deep in proportion as that of a 
 watch-glass. This little net can easily be carried in 
 the pocket, and when wanted can be attached to a stick 
 at a moment's notice. 
 
 A very useful little net, 
 which, however, requires the 
 aid of the tinman, is here 
 depicted. The reader will 
 see that it is made of a strip of tin bent into a spoon- 
 like shape, and with a net fastened at the bottom, 
 The great advantage of this net is that the high walls 
 are very effectual in inclosing any quickly moving 
 creature, and prevent it from being washed out of 
 the net on its being raised to the surface. The rneshes 
 of the net need not be very close, as a mesh will always 
 secure an insect of only half its diameter. 
 
 It is convenient for many reasons to have the nets 
 
SPONGES. 171 
 
 and other apparatus made in such a manner that they 
 can be carried without attracting observation, for at 
 the best of times the microscopic angler is sure to 
 be beset with inquisitive boys of all sizes, who cannot 
 believe that any one can use a net in a pond except for 
 the purpose of catching fish, and is therefore liable to 
 have his sanity called in question, and his proceedings 
 greatly disturbed. However, by a little judicious 
 administration of " soft sawder " and a few pence, the 
 enemies may generally be converted into allies, and 
 rendered extremely useful. 
 
 SPONGES and their structures are very interesting. 
 They consist chiefly of a very thin gelatinous substance 
 not unlike that of the Amoeba, which is spread over a 
 horny skeleton, which skeleton is sustained by an 
 internal arrangement of spiculse, mostly of a flinty 
 nature, but sometimes being chalky in their substance. 
 The gelatinous envelope is covered with cilia, by means 
 of which the water is forced to circulate throughout the 
 entire sponge, entering through the little apertures and 
 being expelled through the larger holes. A portion of 
 this substance with its ciliurn is shown at fig. 12. 
 Fig. 14 shows this process in a Sponge (Grdntia). 
 
 The little granules which afterwards become mature 
 sponges are also thrown from the parent in the same 
 
172 SPICUL^E XOCTILUCA. 
 
 manner. One of these bodies covered with cilia is 
 shown at fig. 18. When ejected from the parent, they 
 swim merrily about for some time, but at last settle 
 down and become fixed for the rest of their life. During 
 
 o 
 
 the life of a sponge it is coloured, and often vividly, 
 with various tints : but after the death of the living 
 
 * o 
 
 portion, the bare horny skeleton is left. 
 
 Two forms of sponge spiculse are shown at figs. 8 
 and 20. The shapes, however, which these curious 
 objects assume are almost innumerable. In them may 
 be seen accurate likenesses of pins, needles, marlinspikes, 
 cucumbers, grappling-hooks, fish-hooks, porters' -hooks, 
 calthrops, knife-rests, fish-spears, barbed arrows, spiked 
 globes, war-clubs, boomerangs, life-preservers, and many 
 other indescribable forms. They may be obtained by 
 cutting sponge into thin slices, and soaking it in 
 liquor potassse or any other substance that will dis- 
 solve the horny skeleton and leave the flinty spiculae 
 uninjured. 
 
 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 disturbed ; 
 the wake of a boat, for example, leaving a luminous 
 track as far as the eye can reach. This phosphorescence 
 is caused by many animals resident in the sea, but 
 chiefly by the little creature represented at fig. 9, the 
 
MEDUSA- iM.KAMINIFERA, 173 
 
 Noctihica, myriads of which may be found in a pail ,of 
 water dipped at random from the glowing waves. A 
 tooth of this creature more magnified is shown imme- 
 diately above. 
 
 In my "Common Objects of the Sea Shore" the 
 Actiniae or Sea- Anemones are treated of at some length. 
 At fig. 16 is shown part of a tentacle flinging out the 
 poison-darts by which it secures its prey; and fig. 17 is 
 a more magnified view of one of these darts and its case. 
 
 The Jelly-Fishes, or Medusae, are partially represented 
 at fig. 28, &c. This represents a very small and very 
 pretty Medusa, called Thaumantias. When touched or 
 startled, each of the purple globules round the edge 
 flashes into light, producing a most beautiful and 
 singular appearance. Fig. 29 exhibits the so-called 
 compound eye of another species of Medusa. The 
 reproduction of these creatures is too complicated a 
 subject for the small space allowed in these pages, but 
 is partially illustrated by figs. 26 and 27. Fig. 26 is 
 the Hydra tuba, a creature long thought to be a 
 distinct animal, but now known to be the young of 
 a Medusa, which does not itself attain maturity, but 
 throws off its joints, so to speak, each of which be- 
 comes a perfect Medusa. One of these joints is shown 
 at fig. 27. 
 
 A large group of microscopic organisms is known to 
 
174 ZOOPHYTES. 
 
 zoologists under the name of Foraminifera, on account 
 of the numerous holes in their beautiful shells. Their 
 real position in the animal kingdom is some what doubtful. 
 The holes are intended to permit the passage of certain 
 thread-like tentacles, and are variously arranged upon 
 the shell. Chalk is largely mixed with these minute 
 shells, and whole tracts of country are composed almost 
 wholly of these little creatures in a fossilized state. 
 They may often be found in sand, and separated by 
 spreading the sand on black paper and examining it 
 with a glass. Examples of these creatures are given in 
 Plate IX. fig. 4 (Miliolina), and Plate XII. fig. 7, which 
 is a portion of the shell to show the holes, fig. 13 
 (Polystomella), fig. 14 (Truncatulina), fig. 15 (Poly- 
 morphina), fig. 16 (Miliolina, partly fossilized), fig. 18 
 (Lagena), and fig. 20 (Biloculma). 
 
 The Zoophytes or Polypi are represented by several 
 examples. These creatures are soft and almost gela- 
 tinous, and are furnished with tentacles or lobes by 
 which they can catch and retain their prey. In order 
 to support their tender structure they are endowed 
 with a horny skeleton, sometimes outside and some- 
 times inside them, which is called the polypidon. 
 They are very common on our coasts, where they may 
 be found thrown on the shore or may be dredged up 
 from the deeper portions of the sea. 
 
BUGULARIA. 175 
 
 Fig. 1 3 is a portion of one of the commonest genera, 
 Sertularia, showing one of the inhabitants projecting 
 its tentacles from its domicile. Fig. 15 is the same 
 species, given to show the egg-cells. This, as well as 
 other zoophytes, is generally classed among the sea- weeds 
 in the shops that throng all watering-places. Fig. 19 
 is a very curious zoophyte called Anguinaria, or Snake- 
 head, on account of its shape, the end of the polypidon 
 resembling the head of the snake, and the tentacles look- 
 ing like its tongue as they are thrust forward and rapidly 
 withdrawn. Fig. 21 is the same creature on an enlarged 
 scale, and just below is one of its tentacles still more 
 magnified. Fig. 23 is the Ladies'-slipper zoophyte; and 
 fig. 24 is called the Tobacco-pipe zoophyte. 
 
 Fig. 22 is a portion of the Bugularia, with one of 
 the curious "birds'-head" processes. These appendages 
 have the most absurd likeness to a bird's head, the 
 beak opening and shutting with a smart snap, so smart 
 indeed that the ear instinctively tries to catch the 
 sound, and the head nodding backward and forward 
 just as if the bird were pecking up its food. On Plate 
 XII. fig. 2, is a pretty zoophyte called Gemellaria, on 
 account of the double or twin-like form of the cells ; 
 and fig. 5 represents the Antennularia, so called on 
 account of its resemblance to the antennae of an insect. 
 Fig. 22 is aa example of a pretty zoophyte found para- 
 
176 ENTOMOSTRAO A ZOE A. 
 
 sitic on many sea-weeds, and known by the name of 
 Membranipora. Two more specimens of zoophytes may 
 be seen on Plate XII. as they appear under polarized 
 light. Fig. 17 is the Cellularia reptans ; and fig. 20 is 
 the Bowerhankia. 
 
 Our space is so rapidly diminishing, that we can 
 only give one example of the curious group of animals 
 called Entom6straca. They belong to the great class 
 of Crustaceans, and are found both in fresh and salt 
 water. Their shell is often transparent, so as to per- 
 mit their limbs to be seen through its substance, and 
 when boiled it gets red like that of the lobster. Their 
 shape is extremely various, but that of the example 
 at Plate IX. fig. 31, the Fresh-water Flea (Daphnia), 
 affords a good illustration of their general appearance. 
 The Cyclops, another fresh-water example, is very com- 
 mon in our ponds, and may be known by the long body, 
 the single eye in the head, and the egg-bags depending 
 from the sides of the females. 
 
 Fig. 25 is the larva of the common Crab, once 
 thought to be a separate species, arid described as such 
 under the title of Zoea. I may as well mention that 
 many of the objects here mentioned in a cursory man- 
 ner are to be found described more at length in my 
 two previous manuals, the " Common Objects " of the 
 Sea-shore and Country. 
 
SEBPULA MUSSEL. 177 
 
 Parts of the so-called feet of the Serpula are shown 
 at fig. 36, where the spears or " pushing-poles " are 
 seen gathered into bundles as used by the creature. 
 One of them on a larger scale is shown at fig. 32. 
 
 The structure of shell, e.g. oyster-shell, is well 
 shown in three examples : Fig. 34 is a group of artificial 
 crystals of carbonate of lime ; and on figs. 38 and 39 
 may be seen part of an oyster-shell, showing how it 
 is composed of similar crystals aggregated together. 
 Their appearance under polarized light may be seen on 
 Plate XI. figs. 1 and 6. 
 
 Before entering upon the Echinoderms, we will cast 
 a glance at a beautiful structure found upon the gills 
 of the common Mussel. Fig. 39 shows a portion of 
 the gills in order to exhibit the numerous cilia with 
 which it is covered. It is a valuable example, as the 
 cilia attain a very large size on this organ, being about 
 one five-hundredth of an inch in length. Their object 
 is of course to produce circulation in the water which 
 bathes the gills. 
 
 The old story of the goose-bearing tree is an example 
 how truth may be stranger than fiction. For if the 
 
 fable had said that the mother goose laid eggs which 
 
 
 
 grew into trees, budded and flowered, and then produced 
 new geese, it would not have been one whit a stranger 
 tale than the truth. Plate IX., fig. 33, shows the young 
 state of one of the common Star-fishes (Comdtula\ 
 
 N 
 
178 PEDICILLARI^. 
 
 which in its early days is like a plant with a stalk, but 
 afterwards breaks loose and becomes the wandering sea- 
 star which we all know so well. In this process there 
 is just the reverse to that which characterizes the 
 barnacles and sponges, where the young are at first free 
 and then become fixed for the remainder of their lives. 
 Fig. 30 is the young of another kind of Star-fish, the 
 long-armed Ophhira, or Snake-Star. 
 
 Fig. 37 is a portion of the skin of the common Sun- 
 star (Solaster), showing the single large spine sur- 
 rounded by a circle of smaller spines, supposed to be 
 organs of touch, together with two or three of the 
 curious appendages called Pedicillarisa. These are found 
 on Star-fishes and Echini, and bear a close resemblance 
 in many respects to the bird-head appendages of the 
 zoophytes. They are fixed on foot-stalks, some very 
 long and others very short, and have jaws which 
 open and shut regularly. Their object is doubtful, 
 unless it be to act as police, and by their continual 
 movements to prevent the spores of algae, or the young 
 of various marine animals, from effecting a lodgment 
 on the skin. A group of PedicillariaB from a Star-fish 
 is shown on a large scale on Plate XIT. fig. 6, and 
 fig. 9 of the same plate shows the Pedicillarise of the 
 Echinus. 
 
 Upon the exterior of the Echini or Sea-Urchins are 
 a vast number of spines, having a very beautiful struc- 
 
CORALLINES. ] 79 
 
 ture, as may be seen by fig. 35, Plate IX., which is 
 part of a transverse section of one of these species. 
 An entire spine is shown on Plate XII. fig. 12, and 
 shows the ball-and-socket joint on which it moves, and 
 the membranous muscle that moves it. Fig. 8 is the 
 disc of the Snake-Star as seen from below. Fig. 1 is 
 a portion of skin of the Sun-Star, to show one of the 
 curious madrepore-like tubercles which are found upon 
 this common Star-fish. Fig. 3 is a portion of Cuttle 
 " bone " very slightly magnified, in order to show 
 the beautiful pillar-like form of its structure ; and 
 fig. 4 is the same object seen from above. When 
 ground very thin, this is a magnificent object for the 
 polarizer. 
 
 One or two miscellaneous objects now come before 
 our notice. Fig. 1 1 is one of those curious marine 
 plants, the Corallines, which are remarkable for de- 
 positing a large amount of chalky matter among their 
 tissues, so as to leave a complete cast in white chalk 
 when the coloured living portion of the plant dies. 
 The species of this example is Jania rubens. 
 
 Fig. 19 is part of the pouch-like inflation of the 
 skin, and the hairs found upon the Rat's tail, which is 
 a curious object as bearing so close a similitude to 
 fig. 22, the Sea-mat zoophyte. Fig. 23 is a portion 
 of the skin taken from the finger, which has been 
 injected with a coloured preparation in order to show 
 N2 
 
180 INJECTION COLOUR OF THE FROG. 
 
 the manner in. which the minute blood-vessels or 
 "capillaries" are distributed; and fig. 26 is a portion 
 of a Frog's lung, also injected. 
 
 The process of injection is a rather difficult one, and 
 needs tools of some cost. The principle is simple enough, 
 being merely to fill the blood-vessels with a coloured 
 substance, so as to exhibit their form as they appear 
 while distended with blood during the life of the 
 animal. It sometimes happens that when an animal is 
 killed suddenly without effusion of blood, as is often seen 
 in the case of a mouse caught in a spring trap, the 
 minute vessels of the lungs and other organs become 
 filled with coagulated blood, so as to form what 
 is called a natural injection, ready for the micro- 
 scope. 
 
 Before leaving the subject, I must ask the reader to 
 refer again for a moment to the Frog's foot on Plate X. 
 and to notice the arrangement of the dark pigment 
 spots. It is well known that when frogs live in a clear 
 sandy pond, well exposed to the rays of the sun, their 
 skins are bright yellow, and that when their residence 
 is in a shady locality, especially if sheltered by heavy 
 overhanging banks, they are of a deep blackish brown 
 colour. Moreover, under the influence of fear, they 
 will often change colour instantaneously. The cause of 
 this curious fact is explained by the microscope. 
 
 Under the effects of sunlight the pigment granules 
 
COAL POLARIZED LIGHT. 181 
 
 are gathered together into small rounded spots, as seen 
 on the left hand of the figure, leaving the skin of its 
 own bright yellow hue. In the shade the pigment 
 granules spread themselves so as to cover almost the 
 entire skin and to produce the dark brown colour. In 
 the intermediate state, they assume the bold stellate 
 form in which they are shown on the right hand of the 
 round spots. 
 
 Figs. 24 and 25 are two examples of Coal, the 
 former being a longitudinal and the latter a transverse 
 section, given in order to show its woody character. 
 Fig. 17 is a specimen of Gold-dust intermixed with 
 crystals of quartz sand, brought from Australia ; and 
 fig. 21 is a small piece of Copper-ore. 
 
 Every possessor of a microscope should, as soon as 
 he can afford it, add to his instrument the beautiful 
 apparatus for polarizing light. The optical explanation 
 of this phenomenon is far too abstruse for these pages, 
 but the practical appliance of the apparatus is very 
 simple. It consists of two prisms, one of which, called 
 the polarizer, is fastened by a catch just below the stage ; 
 and the other, called an analyser, is placed above the eye- 
 piece. In order to aid those bodies whose polarizing 
 powers are but weak, a thin plate of selenite is 
 generally placed on the stage immediately below the 
 object. The colours exhibited by this instrument are 
 gorgeous in the extreme, as may be seen by Plate XL, 
 
182 MICROMETER. 
 
 which affords a most feeble representation of the 
 glowing tints exhibited by the objects there depicted. 
 The value of the polarizer is very great, as it often 
 enables observers to distinguish, by means of their 
 different polarizing powers, one class of objects from 
 another. 
 
 Another instrument really essential to the micro- 
 scopist is the micrometer, for the purpose of measuring 
 the minute objects under examination. The cheapest 
 and simplest is the Stage Micrometer, which may be 
 purchased for five shillings at the opticians'. It consists 
 simply of a glass slide on which are ruled a series of 
 lines, some the hundredth of an inch apart, and others 
 the thousandth. This is laid on the stage, and the 
 object placed upon it, when with a little management 
 the lines may be made to cut the objects so as to give 
 their dimensions. 
 
 Another simple and even more accurate way is to 
 slip the camera lucida on the eye-piece, and sketch 
 the object as mentioned on page 51. Then remove the 
 object, substitute the stage micrometer, and sketch 
 the lines upon the drawing of the object. It will be 
 also evident that if the " hundredth " lines coincide 
 with an inch, the object is magnified one hundred 
 diameters ; if with two inches, two hundred diameters, 
 and so on. 
 
INDEX. 
 
 Air-bubbles, 95. 
 
 Ferns, 113. 
 
 Pond-hunting, 166. 
 
 Algae, 100. 
 
 Fibre, white, 153. 
 
 Pouches, Rat's tail, 179. 
 
 Anemones, Sea, 173. 
 
 Flint, or Silex, 68, 108. 
 
 Preservative Fluids, 98. 
 
 Antennae, 119. 
 
 FootpadsofFly,&c.l32. 
 
 Proboscis of Fly, 131. 
 
 Ants, 119. 
 
 Foraminifera, 173. 
 
 Binged or annulated 
 
 Balancers of Fly, 138. 
 
 Forceps, 16. 
 
 cells, 24, 58. 
 
 Bark, 67. 
 
 Frog, colour, 180. 
 
 Rotifers, 165. 
 
 Blights, 112. 
 
 Frog-plate, 157. 
 
 Sap, 155. 
 
 Blood, 155. 
 
 Gizzard of Insects, 135. 
 
 Saws of Sawfly, 141. 
 
 Bone, 149. 
 
 Glass tubes, 22. 
 
 Scalariform deposit, 47. 
 
 Breathing-tubes, 127. 
 
 Gold dust, 181. 
 
 Scales of Fish, 144. 
 
 Camera Lucida, 51. 
 
 Gory-dew, 100. 
 
 Scales of Insects, 138. 
 
 Canada balsam, 86. 
 
 Gristle, 151. 
 
 Scent-glands, 64. 
 
 Cartilage, 151. 
 
 Hairs of Animals, 142. 
 
 Seaweeds, 115. 
 
 Cells, animal, 151. 
 
 Hairs of Insects, 139. 
 
 Secondary deposit, 44. 
 
 
 
 Seeds 83. 
 
 mounting in, 95. 
 
 Heads of Insects,' 128. 
 
 Serpula, 177. 
 
 
 Infusoria 160 
 
 Shell 176. 
 
 t h'l R7 
 
 
 Silk 'l41 
 
 Ceramidia, 117. 
 
 Insects, 119. 
 
 Simple Microscopes, 9. 
 
 Chlorophyll, 40. 
 
 Introduction, 1. 
 
 Skin of Beetle larva, 135. 
 
 Cilia of Mussel, 177. 
 
 Jaws of Insects, 129. 
 
 Human, 147. 
 
 Circulation, 156. 
 
 Jelly Fish, 173. 
 
 Spiculae, 171. 
 
 Coal, 181. 
 
 Legs of Insects, 132. 
 
 Spines of Hedgehog, 
 
 Coddington Lens, 24. 
 
 Ligament, elastic, 153. 
 
 146. 
 
 Compound Microscope, 
 
 Linen, 143. 
 
 Spiracles, 127. 
 
 26. 
 
 Live-box, 31. 
 
 Spiral deposit, 46. 
 
 Condenser, 33. 
 
 Mare's tail, 115. 
 
 Sponges, 171. 
 
 Confervoid Algae, 103. 
 
 Medusae, 173. 
 
 Sporanges, 115. 
 
 Conjugation, 101. 
 
 Micrometer, 182. 
 
 Stage forceps, 30. 
 
 Copper, 181. 
 
 Mildew, 112. 
 
 Stanhope Lens, 25. 
 
 Corallines, 179. 
 
 Mosses, 113. 
 
 Starch, 70. 
 
 Cotton, 143. 
 
 Mould, 112. 
 
 Star Fishes, 177. 
 
 Cuttle Fish, 179. 
 
 Mouths (vegetable), 49. 
 
 Stellate tissue, 41. 
 
 Desmidiaceae, 103. 
 
 Muscle, 153. 
 
 Sting of Insects, 141. 
 
 Diaphragm, 35. 
 
 Muscles of Insects, 154. 
 
 Stomach of Insects, 135. 
 
 Diatomaceae, 108. 
 
 Nails, 151. 
 
 Stomata, 49. 
 
 Dipping-tubes, 23. 
 
 Needles, 16. 
 
 Suckers of Foot, 134. 
 
 Dissecting Microscope, 
 
 Nerve, 154. 
 
 Sweat ducts, 147. 
 
 12. 
 
 Nets, 170. 
 
 Teeth, 152. 
 
 Dotted Ducts, 45. 
 
 Netted or reticulated 
 
 Tetraspores, 117. 
 
 Dry mounting, 90. 
 
 Ducts, 46. 
 
 Tongue of Cricket, 131. 
 
 Ducts and Vessels, 45. 
 
 Nucleus, and Nucleo- 
 
 Turn-table, 94. 
 
 Echini, 178. 
 
 lus, 39. 
 
 Urchins, Sea, 178. 
 
 Echinodermata, 177. 
 
 Oil-cells, 47. 
 
 Uses of the Micro- 
 
 Eggs of Insects, 140. 
 
 Oscillatoriae, 107. 
 
 scope, 3. 
 
 Entomostraca, 176. 
 Epidermis, animal, 148. 
 
 Paps of Aphis, 128. 
 PediciUariae, 178. 
 
 Varnish (vegetable), 75. 
 Vittae, 68. 
 
 
 Petals 76 
 
 Volvox 111 
 
 Epithelium, 148. 
 
 Pigment, 150. 
 
 Wings of Insects, 136. 
 
 Essential oil, 64. 
 
 Pins, 21. 
 
 Wool, 142. 
 
 Extemporized instru- 
 
 Pitted structure, 40. 
 
 Yeast Plant, 112. 
 
 ments, 6. 
 
 Polarized light, 181. 
 
 Zoea, 176. 
 
 Eyes, 125. 
 
 Pollen, 78. 
 
 Zoophytes, 174. 
 
 Feathers, 145. 
 
 Polypi, 174. 
 
 Zygnemaceae, 107. 
 
DESCRIPTION OF PLATES. 
 
 FIG 
 1. 
 
 2. 
 
 14. 
 15. 
 16. 
 
 17. 
 
 18. 
 
 19. 
 20. 
 21. 
 22. 
 23. 
 24. 
 25. 
 
 27! 
 
 PAGE 
 
 Strawberry, cellular tissue 38 
 Buttercup leaf, internal 
 
 layer -.89 
 
 Privet, Seed coat, showing 
 
 star-shaped cells . , . 41 
 
 Rush, Star-shaped cells . 41 
 Mistletoe, cells with ringed 
 
 fibre 44 
 
 Cells from interior of Lilac 
 
 bud 45 
 
 Bur-reed (Sparganium), 
 
 square cells from leaf . 40 
 Six-sided cells, from stem of 
 
 Lily 39 
 
 Angular dotted cells, rind of 
 
 Gourd 43 
 
 Elongated ringed cells, 
 
 anther of Narcissus . . 44 
 Irregular star-like tissue, 
 
 pith of Bulrush ... 42 
 Six-sided cells, pith of 
 
 Elder 40 
 
 Young cells from Wheat . 42 
 
 Do. rootlets of Wheat . 42 
 
 Wood-ceUs, Elder ... 48 
 Glandular markings and 
 
 resin, "Cedar" pencil . 47 
 
 Do. Yew 48 
 
 Scalariform tissue, Stalk of 
 
 Fern 47 
 
 Dotted Duct, Willow . . 45 
 
 Do. Stalk of Wheat . . 46 
 
 Wood-cell, Chrysanthemum 48 
 
 Do. Lime-tree .... 48 
 
 Dotted Duct, Carrot . . 46 
 
 Cone-bearing wood, Deal . 47 
 
 Cells, outer coat, Gourd . 54 
 
 Ducts, Elm 46 
 
 Cellular tissue, Stalk of 
 
 Chickweed 42 
 
 Holly-berry, outer coat . . 49 
 
 II. 
 
 1. Cuticle, Buttercup leaf. 
 
 2. Do. Iris 
 
 3. Do. Ivy leaf . . . . 
 
 4. Spiral vessel, Lily . . . 
 
 5. Do. root, (rhizome) Water 
 
 Lily 
 
 6. Ringed vessel, Rhubarb 
 
 .54-5 
 55 
 
 56 
 56 
 
 TIG. PAGE 
 
 7. Chaff, after burning ... 68 
 
 8. Bifid hair, Arabis .... 59 
 
 9. Hair, Marvel of Peru . . 59 
 
 10. End of hair, leaf of Holly- 
 
 hock 65 
 
 11. Hair, Sowthistle leaf . . 60 
 
 12. Do. Tobacco 61 
 
 13. Do. Southernwood ... 59 
 
 14. Group of hairs, Hollyhock 
 
 leaf 66 
 
 15. Hair, Yellow Snapdragon . 62 
 
 16. Do. Moneywort .... 62 
 
 17. Hair, Geum 62 
 
 18. Do. Flower of Heartsease 59 
 
 19. Do. Dockleaf .... 59 
 
 20. Do. Throat of Pansy . . 66 
 
 21. Do. Dead-nettle flower . 66 
 
 22. Do. Groundsel .... 60 
 
 23. Cell, Beech-nut .... 68 
 
 24. Do. Pine cone .... 67 
 
 25. Vitta, Caraway seed ... 68 
 
 26. Cork 67 
 
 27. Hair, flower of Garden Ver 
 
 bena 67 
 
 28. Do. fruit of Plane . . 62 
 
 29. Do. do 63 
 
 30. Do. do 62-3 
 
 31. Do. Lobelia 66 
 
 32. Do. Cabbage 59 
 
 33. Do. Deadnettle flower . 60 
 
 34. Do. Garden Verbena flower 62 
 
 35. Fruit-hair, Dandelion . . 64 
 
 36. Hair, Thistle leaf .... 60 
 
 37. Do. Cactus 65 
 
 38. Do. do 65 
 
 39. Do. Virginian Spider-wort 60 
 
 40. Do. Lavender .... 63 
 
 41. Section, Lavender leaf, 
 
 Hairs and perfume-gland. 63 
 
 42. Section, Orange peel ... 64 
 
 43. Sting of Nettle 61 
 
 44. Hair, Marigold flower . . 65 
 
 45. Do. Ivy. 66 
 
 HI. 
 
 1. Laurel leaf, transverse sec- 
 
 tion 75 
 
 2. Starch, Wheat 73 
 
 3. Do. from Pudding . . 74 
 
 4. Do. Potato 72 
 
 5. Outer Skin, Capsic'im pod . 76 
 
DESCRIPTION OF PLATES. 
 
 185 
 
 FIG. PAGE 
 
 6. Starch, Parsnip .... 73 
 7. Do. Arrow Root, West 
 
 FIG. PA.GB 
 
 5. Ditto, end more magnified . 104 
 6. Pediastrum . . 104 
 
 Indian ... 74 
 
 7 Scenedesmus 105 
 
 8. Do. " Tons les Mois " . 74 
 
 8. Oscillatoria 107 
 
 9. Do. in cell of Potato . 72 
 
 9. Spirogyra . . . . 107 
 
 10 Do. Indian Corn ... 74 
 
 10. Tyndaridea 107 
 
 11 Do Sago . 74 
 
 11 Do spore 108 
 
 12. Do. Tapioca 74 
 
 12. Sphserozosma . .106 
 
 13. Root, Yellow Water-Lily . 75 
 
 13. Chlorococcus 103 
 
 14 Starch Rice . 75 
 
 14 Scenedesmus 106 
 
 15. Do. Horsebean .... 75 
 16 Do Oat .... 75 
 
 15. Pediastrum, to show cells . 105 
 16 Ankistrodesmus 104 
 
 17. Pollen, Snowdrop .... 79 
 
 17. Cosmarium ... . . 106 
 
 18 Do Wallflower . 79 
 
 18. Desmidium 105 
 
 19. Do. Willow Herb, a pol- 
 len tube 79-80 
 
 19. Cosmarium, formation of 
 Resting Spore . . 106 
 
 20 Do Violet .... 81 
 
 20 Cocconema lanceolatum 108-9 
 
 21. Do. Musk Plant ... 81 
 22. Do. Apple 81 
 
 21. Diatoma vulgare .... 108 
 Do. larger frustules at 
 
 23. Do Dandelion . 81 
 
 the side 108 
 
 24. Do. Sowthistle. ... 81 
 25. Do Lily .... 81 
 
 22. Volvox globator . . . .111 
 Do single green body 
 
 26. Do. Heath 82 
 
 
 27. Do. Heath, another species 82 
 28 Pollen Furze . 82 
 
 23. Synedra 109 
 24. Gomphonema acuminatum 109 
 
 29. Do. Tulip 82 
 30. Petal Pelargonium . . 76 
 
 Do. larger frustules, 
 below 109 
 
 31. Do. Periwinkle .... 77 
 32. Do. Golden Balsam . . 78 
 33. Do. Snapdragon ... 78 
 34. Do. Primrose .... 78 
 35. Do. Scarlet Geranium . 78 
 36. Pollen Crocus . 83 
 
 25. Yeast 112 
 26. Sarcina ventriculi . . .112 
 27. Eunotia diadema .... 109 
 28. Melosira varians .... 110 
 Do. two bleached frus- 
 tules . . . . 110 
 
 37. Do. Hollyhock .... 83 
 38. Fruit, Galium, Goose-grass. 84 
 39. A hook of ditto more mag- 
 nified 84 
 
 29. Cocconeis pediculus . . . 110 
 30. Achnanthis exilis .... 110 
 31. Navicula amphisbrena . . Ill 
 32. Uredo, "Red-rust" of corn 112 
 
 40. Seed, Red Valerian ... 84 
 41. Portion of Parachute of 
 same, more magnified . 84 
 42. Seed Foxglove . 85 
 
 33. Puccinea, Mildew of corn . 113 
 34. Botrytis, mould on grapes . 113 
 Do. Sporules, beside it . 
 35. Do. parasitica Potato blight 113 
 
 43. Seed, Sunspurge .... 85 
 44. Parachute, Dandelion seed 84 
 
 36. Ectocarpus siliculosus . .115 
 37. Ulva latissima 116 
 
 45. Seed, Dandelion 85 
 
 38. Polypodium 113 
 
 46. Do. Hair of Parachute . 85 
 47. Do. Yellow Snapdragon . 85 
 48 Do. Mullein 86 
 
 Do. single spore, below 113 
 39. Moss capsule, Hypnum . . 114 
 40. Mare's-tail, Equisetum, a .\-I-IA 
 
 49. Do. Robin Hood ... 86 
 50. Do. Bur-reed .... 86 
 51. Do. Willow Herb ... 86 
 52. Do. Musk Mallow ... 86 
 
 IV. 
 1. Gory Dew, Palmella cru- 
 enta 100 
 
 Do. do. & and c. f 114 
 41. Porphyra laciniata . . . 116 
 
 V. 
 
 1. Rose Leaf, with fungus . . 113 
 2. Moss capsule, Polytrichum. 114 
 3. Jungermannia, capsule . .114 
 4. Do. an elater more magnifiedll4 
 
 2. Palmoglaea macrococca . . 101 
 3 Protococcus pluvialis ci in 
 
 5. Leaf of Moss, Sphagnum . 114 
 6 Rootlet Moss 114 
 
 its motile, b, in its fixed 
 state, c, zoospores . .102 
 4. Closterium . . 104 
 
 7. Puccinia, from Thistle . . 113 
 8. Jungermannia, leaf . . .114 
 9. Scale from stalk of male fern 114 
 
18(5 
 
 DESCRIPTION OF PLATES. 
 
 FIG. PAGE 
 
 10. Uredo 113 
 
 TIG. PAGE 
 
 4. Head, Violet Ground Beetle 
 
 11. Sphacelaria filicina . 116 
 
 (Carabus) 129 
 
 12. Do. top, more magnified . 116 
 13. Seaweed, showing fruit . . 116 
 14. Do. fruit, more magnified 116 
 15 Ceramium 117 
 
 5. Tongue, Cricket .... 131 
 6. Do. do 131 
 7. Head, Scorpion Fly (Pan- 
 orpa) 130 
 
 16. Capsule, Halidrys. . . .117 
 
 8. Leg Ant 132 
 
 17. Spore of do 117 
 18. Polysiphonia parasitica . . 117 
 19. Do. stem more magnified 117 
 
 9. Proleg, Caterpillar . . .132 
 10. Do. do. single, hook . . 132 
 11. Proboscis Fly 130 
 
 20. Do. Capsule, tetraspores 
 escaping 117 
 
 12. Do. do. "modified trachea" 131 
 13. Part of Foreleg of Water 
 
 21. Do. fruit, another form . 117 , 
 22. Ceramium, fruit . . . .116 
 23. Myrionema, parasitic Sea- 
 weed . 117 
 
 Beetle (Acilius) . ... 134 
 14. Do. large sucker . . . 135 
 15. Leg, long-legged Spider 
 (Phalangium) 132 
 
 24. Delesseria sanguinea, Frond 118 
 25. Cladophora . . 117 
 
 16. Do. Harvest-bug (Trom- 
 bidium) . . 132 
 
 26. Ptilota elegans 118 
 
 17 Do. Glow-worm 132 
 
 27. Enteromorpha clathrata . 118 
 
 18. Do. Dung-fly 133 
 
 28. Nitophyllum laceratum . 118 
 VI. 
 1. Antenna, Cricket .... 121 
 2. Do. Grasshopper . . .122 
 3. Do. Staphylinus . . .122 
 4. Do. Cassida 122 
 
 19. Do. Asilus 133 
 20. Do. Acarus of Dor-beetle 133 
 21. Claws and Pad, Ophion . . 133 
 22. Wings, Humble Bee . . .137 
 23. Do 137 
 24. Wing hooks, hind wing of 
 At>his 137 
 
 5. Do. Staphylinus . . .122 
 6. Do. Weevil .... 122 
 
 25. Wing hooks, Humble Bee . 137 
 26 Foot Flea 132 
 
 7. Do. Pyrochroa . . . .122 
 8. Do. Butterfly, Tortoise- 
 
 cVipll 1 9/1 
 
 27. Stomach and gastric teeth, 
 Bee 136 
 
 9. Do. Gnat, male . . . .124 
 10. Do. Syrphus . . . 123 
 
 28. Three teeth of do. ... 136 
 29. Cast skin, Larva of Tortoise 
 
 11. Do. Cockchaffer, male . 122 
 12. Do. Ground Beetle . .123 
 13. Do. Ermine Moth . . .124 
 14. Do. Tiger Moth. . . . 124 
 
 Beetle (Cassida) . . .135 
 30. Balancer, Blow fly ... 138 
 31. Wing, Midge (Psychoda) . 137 
 32. Do. do. part of a nervure 
 with scales 137 
 
 15. Antenna, Blowfly .... 121 
 16. Do. do. section .... 121 
 17. Do. Ichneumon .... 121 
 18. Eye of Butterfly, Atalanta. 125 
 19 Eyes Bee . . . 125 
 
 33. Stomach and gastric teeth, 
 Grasshopper 135 
 34. Spiracle, Wire-worm . . .127 
 
 20. Eye, Death's Head Moth . 125 
 21. Breathing-tube, Silkworm . 127 
 
 VIII. 
 1. Boat-fly leg 135 
 
 22. Eye, Heliophilus . . . 125-6 
 23 Eye Lobster 126 
 
 2. Gadfly, empty egg . . . . 140 
 
 24. Do. Aphis of Geranium . 128 
 25. Head, Parasite of Tortoise 128-9 
 26. Hind leg, Aphis of Geranium 132 
 27 Head Gnat 130 
 
 3. Diamond Beetle, scale . . 139 
 4. Scale, Fritillary, Adippe. . 138 
 5. Egg, Tortoiseshell Butterfly 140 
 6. Head and Eyes, Zebra Spi- 
 
 28. * Paps" of Aphis . . . .128 
 
 der 126 
 7 Eyes Bed-Bu " 140 
 
 29. Head, Sheep-tick . . . .128 
 30. Foot, Tipula 132 
 VII. 
 1. Tongue, Hive Bee . . . .129 
 2. Do. Tortoiseshell Butterfly 130 
 3. Do. do. one of the barrel- 
 shaped bodies .... 130 
 
 8. Scale, Death's-Head Moth . 138 
 9. Sting, Wasp 141 
 10. Scale, battledore, Azure 
 Blue 138 
 11. Do. ordinary scale . . .138 
 12. Eye, Harvest Spider . . .126 
 13. Wing Membrane, Azure Blue 140 
 
DESCRIPTION OF PLATES. 
 
 187 
 
 'tO. PAGB 
 
 14. Scale, Anthocera cardaminis 138 
 15. Do. Peacock Butterfly . 138 
 16. Do Tiger Moth. . . .138 
 17. Do Thi-h of Tiger Moth 140 
 
 FIG. PA.GB 
 
 22. Bugularia circularia . . .175 
 23. Zoophyte, Ladies' Slipper . 175 
 24. Zoophyte, Tobacco-pipe 
 bearer 175 
 
 18. Wing and Scales, Azure 
 Blue 140 
 
 25. Zoea, Young of Crab . . .176 
 26. Hydra tuba 173 
 
 19. Scale Lepisma . 139 
 
 27. Medusa, cast off from above 173 
 
 20. Saws, Sawfly 141 
 
 28. Naked-eyed Medusa, Thau- 
 
 21. Scale, Podura .... 139 
 
 mantias 173 
 
 22. Hair, Black Human . . .142 
 23. Do. Human Beard . . .142 
 24. Do. do. aged 142 
 
 29. Compound eye, Medusa . .173 
 30. Larva, Snake Star . . .178 
 31. Water Flea 176 
 
 25. Do. Humble Bee ... 143 
 26. Do. Tiger Moth, Larva . 143 
 27. Do. Dormouse 143 
 
 ' 32. Serpula, Pushing Pole . .177 
 33. Comatula, early stage of 
 Starfish .... 177 
 
 28. Do Rat 143 
 
 34. Carbonate of Lime artifi- 
 
 29. Do. do. long hair . . .143 
 30. Do. Sheep 142 
 
 cial 177 
 
 35. Sea Urchin, transverse sec- 
 
 31. Do. Mole 143 
 
 tion of spine 179 
 
 32. Do. Rabbit . . . 143 
 
 36. Serpula, bundle of spears 177 
 
 33. Scale, Greenbone Pike . . 144 
 34. Hair, Red Deer 143 
 
 37. Sunstar, part of skin. . . 178 
 38. Oyster shell in different 
 
 35. Do. fine Sea Mouse 144 
 
 stages 177 
 
 36. Do. do. large . . .144 
 37. Do. do. Badger. . . .143 
 38. Do. do. Long-eared Bat . 143 
 39 Fibre Linen 143 
 
 39. Cilia on mussel . . . .177 
 X. 
 
 40. Do. Cotton .... 143 
 
 1. Skin, Frog ... . 148 
 
 41. Do Silk . . . 143 
 
 2. Blood, Human T. 156 
 
 42. Scale, Perch 144 
 
 3. Do. Pigeon 156 
 
 43. Do. do 144 
 
 4. Do. Proteus . . 156 
 
 
 5. Do Tortoise . 156 
 
 TTT 
 
 6. Do. Frog .... 156 
 
 
 7. Do Fish 156 
 
 1. Amosba diffluens .... 163 
 
 8. Human nail 151 
 
 2. Arcella .... 163 
 
 9. Bone, human . . 149 
 
 3. Sun animalcule .... 164 
 4. Miliolina 174 
 
 10. White fibrous tissue . . .153 
 11. Epithelial cells from tongue 149 
 
 
 12. Feather, Peacock .... 146 
 
 6. Chilodon subdividing . . 164 
 7. Melicerta ringens . . 164 
 
 18. Spine, Hedgehog, transverse 
 section .... . 146 
 
 8 Spicula of Sponge Grantia 172 
 
 14. Pax-wax . . 153 
 
 9. Noctiluca miliaris .... 172 
 10. Rotifer vulgaris . . 165 
 
 15. Epithelial cells from nose . 149 
 16. Bone, Ostrich .... 151 
 
 11. Do. jaws 165 
 
 17. Feather Shaft of Canary's 146 
 
 12. Sponge animalcule. . . . 171 
 13. Sertularia operculata . . .175 
 14. Sponge Grantia . 171 
 
 18. Do. Wild Duck .... 146 
 19. Circulation of blood, Frog's 
 foot . . 157 
 
 15. Sertularia operculata, with 
 ovicells .... 175 
 
 20. Feather, Sparrow .... 146 
 21. Do. Cock's tail . . 146 
 
 16. Actinia, showing weapons . 173 
 17. Do. base of weapon 
 
 22. Fibre, crystalline lens of fish 154 
 23. Nerve 154 
 
 more magnified . . .173 
 18. Sponge granule, ciliated. . 172 
 19. Anguinaria anguina . . . 175 
 20. Spicules of sponge from 
 
 24. Muscle, Meat 154 
 25 Tooth, transverse section . 152 
 26. Do. Longitudinal section. 152 
 27. Sweat duct .... 147 
 
 Oyster Shell 172 
 21. Head of Snake-headed Zoo- 
 phyte - . 17 
 
 28. Eye of Haddock . . . .151 
 29. Myliobates, palate . . .153 
 30. Gristle, Pig 151 
 
188 
 
 fiON OF PLATEb. 
 
 FIG. 
 
 31. Pigment, Human eye . . . 
 32. Do. Wing of Bat . . . 
 
 PAGE 
 
 148 
 148 
 
 FIG. PAGE 
 
 25. Cherrystone, transverse sec- 
 tion . 
 
 33. Do. Shell of Prawn . . 
 XI. 
 
 148 
 
 26. Sugar, Crystals in honey . 99 
 27. Tendon, Ox 
 Calcareous plates. Tooth of Echi- 
 nus 152 
 
 POLARIZED LIGHT. 
 
 1. Carbonate of Lime . . . 
 2 Starfish 
 
 177 
 179 
 
 XII. 
 
 1. Tubercle, Sun-star . . .179 
 2 Zoophyte Gemellaria 175 
 
 3. Thistle down 
 
 84 
 
 3. Cuttle bone 179 
 
 4 Starch Wheat . . 
 
 73 
 
 4. Plate of ditto from above 179 
 
 5 Do Potato 
 
 72 
 
 5 Zoophyte Antennularia 175 
 
 6. Prawn-shell . . ... 
 
 177 
 
 6. Pedicillaria skin of Starfish 178 
 
 7. Starch, Tous les mois . . 
 8. Bone, cancellous . . . . 
 
 74 
 149 
 143 
 
 7. Shell, Foraminifer. . . .173 
 8. Snake-star, disc from below 179 
 9 Pedicillaria Echinus 178 
 
 10. Cow's hair 
 11. Hoof, Donkey, longitudinal 
 
 143 
 
 10. Wing-case, Weevil . . . .139 
 11. Coralline . . 179 
 
 12. Do. transverse . . . . 
 
 
 
 12. Spine, Echinus 179 
 
 13 Nitre Crystals 
 
 99 
 
 13 Foraminifer Polystomella 174 
 
 14. Scale, Eel 
 
 144 
 
 14. Do. Truncatulina 174 
 
 15. Wing, Water-Boatman . . 
 16. Chlorate of Potash, Crystals 
 17. Cellularia reptans . . . . 
 18. Star-shaped hair, Stalk of 
 Yellow Water-Lily . . . 
 19. Teeth, Palate of Whelk . . 
 20. Zoophyte, Bowerbankia. . 
 21. Raphides, i.e. crystalline 
 
 137 
 99 
 176 
 
 65 
 152 
 175 
 
 15. Do. Polymorphina . 174 
 16. ' Do. Miliolina . . .174 
 17. Gold dust, with quartz . . 181 
 18. Foraminifer, Lagena vulgaris 174 
 19. Pouches, Skin of Rat's tail 179 
 20. Foraminifer, Biloculina rin- 
 gens 174 
 21. Ore, Copper 181 
 
 formations in vegetable 
 cells Bulb of Hyacinth . 
 
 
 22. Zoophyte Membranipora pi- 
 losa . 175-6 
 
 22. Do. Rhubarb 
 
 
 23. Human skin injected . .179 
 
 23. Sulphate of Magnesia Crys- 
 tals 
 
 99 
 
 24. Coal, Longitudinal section . 181 
 25 Do Transverse section 181 
 
 24. Bone, Skate . 
 
 149 
 
 26. Lung, Froe . 180 
 
 ft. CLAY, S0N, AND TAYLOR, PRINTERS, BREAD STREET HILL 
 
SEP '. 
 
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