Objects for the microscope : being a popular description of the most instructive and beautiful subjects for exhibition ...

Preface

The first thought of this little book was suggested by an Optician, who, having a large sale for Microscopic Objects, and being often perplexed by the questions of his customers, as to the nature of the objects before them, requested me to write a Catalogue of the Slides in his cabinet, to which he might refer the inquirer.

It was a pleasant occupation ; and, as drawer after drawer was opened, and every slide examined, the description of each swelled the small pamphlet into this little book, whose object is solely to accompany the Object-box and explain its contents. There are no engravings, because the mounted objects are the truest and best illustrations, infinitely more interesting than the highest delineations of art. A little expense and a little trouble will procure them all.

Microscope books there are many, and some of them most excellent ; such as

c Quekett on the Microscope/ c Carpenter on the Microscope/ e Hogg on the Microscope/

e How to Work with the Microscope/ by Beale; but although they abound in illustrations, and give all necessary information for preparing objects, I have myself experienced how much more is learnt by the

VI

PREFACE.

careful study of one slide, the dissection of one flower, than by many hours of mere reading and looking at pictures.

That these works are not read attentively or well understood by many young persons, who now purchase Microscopes and collect objects, seems probable from the remarks which are made and the questions that are asked when looking at preparations from the Vegetable and the Animal Kingdom. We not unfrequently hear the section of an Echinus spine pronounced “very pretty, exactly like a crochet pattern" — the Echinus itself being an unknown thing. Spicules of Holothuria or Gorgonia are brilliant little clubs and crosses ; but what a Holothuria is they cannot imagine. The foot of a Dytiscus, with its cluster of suckers, is like the eye of a peacock's feather ; cells of spiral fibre nothing more than coils of variegated wire ; and the head of Rhingia, with its wonderful eyes, is looked at as a beautiful piece of network. It is the design of this Catalogue to give simply that elementary knowledge of Vegetable and Animal Physiology, which will enable the young student to understand the Slides in the Object-box, and excite the desire to learn more from better books.

It is also hoped that many will be led to purchase the preparations of Whole -mounted Insects , and by the careful study of them take the first steps into the wide and pleasant field of Natural History. As the ear is educated by the study of music, so the eye is educated by a habit of observation. An artist's eye catches the faintest tint of colour, observes the minutest curve in an outline; a physician's eye scans quickly and reads deeply the confused or obscure diagnosis of disease, unperceived by others, and every line in the patient's

PBEFACE.

Yll face or movement of the body is to him an index of the inner life ; the naturalist’s eye, quickened in all its powers by observation, sees the folding of a leaf, the spot upon the wall, the track of an insect on his path, where the untrained eye sees nothing. The Microscope gives this training, if it is rightly used, that is, with intelligent inquiry, with careful reading on the various subjects, as they are suggested by mounted objects,* ** and observation of the living creatures in this beautiful world around us.

None but those who have enjoyed it can tell how refreshing and uplifting to the spirit is an hour at the Microscope — an hour of thoughtful, reverent study of the wisdom, power, and love of God in creation. Science, when it is merely “la grande curiosite,” or when pursued for selfish pleasure and ambition, is not the end for which the Microscope was given to us. There must be a link with the unseen and the eternal, a light from the true wisdom, if our ways are to be the ways of pleasantness, and our paths to end in peace.

Woodeaton Rectory.

* “ Kirby & Spencers Entomology.”

Insecta Britanniea.”

“ Westwood’s Introduction to Entomology.” “ Balfour’s Botany.”

“ Lindley’s Vegetable Kingdom.”

** Unger’s Letters.”

Johnstone on Zoophytes.”

“ Harvey on Seaweeds.”

" Slack’s Marvels of Pond Life.”

Preface To Second Edition

In preparing a second edition of this little work, I have added, besides notices of many new objects now to be obtained, two chapters, one of which touches upon a new class of objects, which, I doubt not, will become very popular ; they are especially adapted for the Binocular Microscope, and the new three-inch Object-glass ; I mean those very small moths called Micro - Lepidoptera , which develop from leaf-mining, leafrolling, and tent-making caterpillars.

The second new chapter is on “ Injected Anatomical Preparations,” noticing those only which are advisable for young students of Natural History, leading them to the interesting study of Comparative Anatomy, and giving, as concisely as possible, the needful information concerning the structure and office of the organs injected.

It was objected to my first edition, by a scientific critic in the ‘ Microscopic Journal/ that I had “a tendency to write, which is a damaging propensity where conciseness is of value.” I must answer this objection.

PREFACE.

IX

The chief end of this new plan of mine is to give a Hand-book for the Microscope, to be used as handbooks are, in the presence of the objects themselves, and not as a mere scientific catalogue, with hard names and notices, which presuppose a greater amount of scientific knowledge than young students ever possess.

It is written for the young of both sexes ; possibly my own daughter has involuntarily guided my peri in writing, to awaken deeper interest than merely scientific arrangement could give, to kindle a high and holy love of the beautiful as the expression of Divine Wisdom, to give with the little Microscopic Moth, not only a curious wonder at its minute perfection, but a glance at its former life and development; also to give, when looking at an injected preparation of animal life, a hint of the mystery that lies beneath the object before us.

To sit for an hour at the microscope, and pass slide after slide upon the stage with superficial attention, is not a worthy occupation for the great spirit within us, neither is it safe for the finite and frail intellect of man to enter upon scientific research into the organisms, systems, and theories of life, without the brightening influence of forethought as to Him who hath woven the intricate web of Creation, and afterthought as to the purpose for which all, and especially the human frame, is so fearfully and wonderfully made. In those injected preparations lie subject of deep thought; if such the care and wisdom bestowed upon the tenement, what must the indweller be, and what its final

X

PREFACE.

destination ? If so delicate the adjustment, so elaborate the mechanism, of the mortal instrument, what careful use and to what right purpose should it be put by its possessor ?

Thus explaining why I talk over the Microscope, I trust that I shall find my apology in many a young heart, who will thus be led to link order and beauty, science and everlasting truth, in pleasant, thoughtful hours with mv little Hand-book.

WOODEATOX KeCTORY; April , 1863.

Contents

ON THE USE OF THE MICROSCOPE.

PAGE

Directions for Mounting Objects 7

„ „ Mounting in Balsam 8

Chapter I

Shapes of Cells — Cell contents — Oil Cells — Hairs of plants —

Cuticle and Stomata — Cuticle of Yucca, of Aloe, of Deutzia Scabra, of Amaryllis — Indian Com — Cuticle of Saccalobium, of Elaeagnus, of Tillandsia, of Onosma, of Opuntia 11

Raphides. — Cuticle of Hyacinth — Raphides from Rhubarb — Anagallis — Spiral fibre — Spiral Cells of Oncidium — Spiral Vessels of Collomia — Spiral Cells of Balsam — Spiral Cells of Sphagnum — Scalariform Vessels 22

Pollen. — Pollen of Mallow, of Hollyhock, of Passion-flower, of (Enothera — A Few Words more on the Pollen — Pollen- tubes — Stamens ., 26

Seeds. — Poppy — Sweet-William — Silene, or Stellaria — Orchis —

Eccremocarpus or Calampelis., 30

Chapter II. Sections Of Wood

Ruscus — Whanghae Cane — Asparagus — Section of Hazel, of Pine, of Yew — Cedar of Lebanon — Vegetable Ivory — Fossil Coniferous Wood — Pine Wood — Section of Cocoa-nut, of Cob-nut, of Snake-wood 32

Moss. — Slides of Dicranum, Funaria, &c., &c. — Spore-cases of Fern — Elaters of Equisetum — Elaters of Jungermannia — Jungermannia Bidentata 35

Fungi. — Slide of Puccini a, or Phragmidium — Blight of Wheat

(Smut) — Uredo Fcetida, or Bunt — Uredo, or iEcidium 42

Xll

CONTENTS.

Chapter III. Infusorial Earths

PAGE

Diatoms of Guano — Naviculae— Navicula Hippocampa — Pleurosigma — Meloseira — Meloseira Borreri — Aclinanthes Longipes — Synedra Ulna — Bacillariae — Gomphonema — Licmophora — Rhabdonema — Grammatophora Marina — Biddulphia— Ampbitetras — Istbmia Obliqua — Arachnoidiscus — Heliopelta — Actinocyclus — Asteromphalus Asterolampra — Coscinodiscus 46

Desmidiacece — Volvox Globator — Closterium — Confervae — Zyg-

nema — Acbyla Prolifera 54

Chapter I. Objects From The Arachnipa

Spider’s Foot — Spider’s Legs — Spider’s Spinnaret’s — Spider’s

Eyes — Spider’s Jaws — Spider’s Palpi — Epidermis of Spider 61

Chapter II. Insect Parts

Tongues of Insects. — Tongue or Proboscis of Hive Bee — Tongue of Wasp — Butterfly’s Tongue or Proboscis — Proboscis or Tongue of Blow-fly — Proboscis of Tabanus, of Gnat, of Empis-fly, of Dioctria — Head of Conops, of Rbingia, or Syrphus, of Drone-fly, or Helopbilus, of Eristalis, of Tipula, of Limnobia, of Hemerobius, of Panorpa — Tongue of Cricket — Gizzard of Cricket — Mouth of Soldier Beetle, Calathus Castelloides, of Brachinus, of Onthopliagus, of Anchomenus, of Crioceris, of Ladybird, of Stepopterus Rufus 68

Antennce. — Antennae of Cockchafer, ofNitidularia, of Hydrophilus, of Elater, of Syrphus, of Blow-fly, of Bee, of Ichneumon, of Argynnis — Palpi of Argynnis — Antennae of Dragon-fly, of Silkworm-moth 83

Spiracles and Tracheae. — Spiracles of Dytiscus — Tracheae of Dytiscus — Spiracles of Cockchafer — of Fly, of Tipula, of Water Larvae — Aerating Leaflet of Libellula — Abdomen of Ephemera, or Spiracles 87

CONTENTS. xiii

PAGE

Circulation of Blood 89

Spiracles of Larvae of Bot-fly 91

Wings of Insects. — Wing of Scatophaga, of House-fly, of Blue-bottle-fly, of Syrphus, of Midge, of Gnat, of Beetle, of Cricket

Scales of Insects. — Scales of Morpho Menelaus, of Polyommatus Argus, of Hipparcbia Janira, of Pontia Brassica, of Silkworm-moth, of Clothes -moth, of Podura, of Lepisma Saccharina 96

Elytra of Diamond Beetle 99

Feet of Insects. — Foot of Syrphus — Leg of Dytiscus, or Dy ticus — Foot of Wasp, of Ophion — Leg of Bee, of Gyrinus, of Brachinus, of Anchomenus, of Calathus Castelloides — Sting of Wasp and Bee, of Gnat, of Tabanus 99

Egg of Bot-fly, or (Estrus 103

Chapter III. Insects Mounted Whole

The Telephorus, or Soldier-beetle — Melophorus Granularis —

Catheretes Urticae — Coccinella, or Lady-bird 105

Hemiptera. — Velia Rivulorum — Notonecta, or the Water Boatman — Reduvius or Bed-bug — Cimex, or Field-bug — Aphis — Aphrophora, or Cuckoo-spit — Thrips Ill

1 lymenoptera. — Tenthredo, or Saw-fly — Cypheus Pygmaeus — Ichneumon fly — Microgaster Glomeratus — Aphidius Avenge — Ephedrus Plagiator — Ceraphron Carpenterii — Chelymorpha Phyllophora, or the Turtle-shaped Leaf-bearer 115

CHAPTER IY.

DIPTEBA.

Culex Pipiens 125

Fty chopter a 129

Scatophaga. — The Family of the Brachycera — The Scatophaga — Lonchoptera — Bibeo — Dolichopus — The Opomyza — Chlorops — Phora — Leptis — Asilus — Em pis — Empis Stercorea — Hilara — Syryhus Pyrastri — Borborus Equinus — Sepedon —

Sepsis 130

The Halteres, Poisers, of Diptera. — Halteres of Blow-fly — Hal-

teres of Tabanus 147

XIV

CONTENTS.

Chapter V. Parasites

The Flea . — The Pygidium of a Flea

Pediculus , or Louse

The Acari , or Tics , Mites. — Acarus Domesticus, or Common Cheese-mites — Acarus Passularum — Acarus Passerinus — Ixodes, or Dog-tick — Melophagus — Stenopteryx — Ornithomyia — Nycteribia — Chelifer — Acarus Gamasus — Trombidium Phalangii — Trombidium Autumnale — W ater-mites — Entozoa

Chapter VI. Microscopic Moths

Nepticula aurella — Nepticuli Malvelli — Nepticula Prunatori — Nepticula Trimaculella — Ceriastoma Scitella — Lithocolletis Sylvella — Lithocolletis Schreberella — Lithocolletis — Trifasciella — Lithocolletis Hortella — Gracilaria Swederella — Gracilaria Syringella — Coleophora Gryphipennella — Ornix Guttea — Lithocolletis Scabiosella — Glyphipteryx Thrasonella — Head of Ochsenheimeria, &c

CHAPTER VL*

PALATES.

Palate of Helix Pomatia — Helix Aspersa — Limax — Helix Hortensis — Helix Nemoralis — Helix Rufescens — Helix Yirgata — Zonites, or Helix Nitida — Palate of Whelk, of Purpurea, of Nasa, of Trochus Ziziphinus, of Trochus Crassus, of Trochus Umbilicatus, of Periwinkle, of Haliotes, or Aumer of Pleurobranch, of Aplysia, of Doris, of Limpet, of Chiton, of Yellow Nerite, of Neritina Fluviatilis, of Lymneus Stagnalis, of Planorhis Cornea, of Paludina, of Cyclastoma

Chapter VII. Slides Of Zoophytes

Anthozoa . — Sertularia Pumila — Sertularia Polyzonias — Sertularia Operculata — Sertularia Rosacea — Laomedea Geniculata — Laomedea Dichotoma — Plumularia Cristata — Plumularia Falcata

Polyzoa. — Gemicellaria — Gemmellaria Loriculata — Gemecelaria, or Notomia Bursaria — Cellularia Avicularia — Flustra Truncata Pustulipora Fossil — Flustra Chartaceae — Cellularia Reptans — Cellularia Ciliata — Crisea Eburnea — CriseaCornuta — Serialaria Lendigera — Fresh Water Zoophytes

PAGE

CONTENTS.

XV

Chapter VIII. Sea-weeds — Marine Algl3e

PAGE

Marine Algae — Callithamnion — Ceramium — Ptilota Plumosa — Plocamium Vulgare, Coccineum — Polysiphonia — Spherococcus — Griffithsia — Gracillaria — Laurentia — Odonthalia — Bonnemaisonnia — Delesseria — Rhodomela — Spyridia Filamentosa - — Chaetospori Wiggii — Halymenia — Dasya — Dasya Arbuscula — Dasya Occellata — Dasya Venusta — Goadby’s Solution for Marine Algae 189

HAIRS.

Human Hair — Hairs of Dormouse and Common Mouse, of Mole, of Bats, of Elephant, of Camel, of Reindeer, of Ornithorhynchus, of Larvae, of Dermestes ; 215

Chapter XIII. Spicules Of Holothurijb

Spicules of Synapta — Spicules of Chirodota — Calcareous Spicules of Doris — Calcareous Skeleton of Doris — Spicules of Gorgonia — Spicules of Aicyonium Digitatum— Section of Echinus Spine 218

XV

CONTENTS.

OBJECTS FOB POLABISCOPE.

Polarized Light — Selenite — Rhinoceros Horn — Whalebone — Elytra of Dytiscus — Cuticle of Deutzia Leaf — Section of Quartz — List of Objects

Chapter XIV. Anatomical Injected Pbepabations

Liver, Human, Rabbit, Pig, Monkey — Villi, Small Intestines of Man, of Monkey, of Pig, of Hog, of Cat, of Rabbit — Duodenum of Mouse — Lung, Human, Monkey, Bear, Puppy, Pig, Cat, Sheep, Fowl, Goose, Turtle, Rattlesnake, Frog, Tortoise — Gill of Eel — Fin of Turtle — Stomach of Mouse — Skin — Palm of Hand — Foot of Cat — Skin of Toad — Ciliary Processes— Eye of Ox — Ear of Mouse — Toe of White Mouse — Kidney — Tongue, Human, Dog, Cat, Mouse — Brain, Human, Cat, Rabbit, Mouse

Chapter XV

Selenite — Acetate of Copper — Sulphate of Copper — Alum — Oxalurate of Ammonia — Purpurate or Murexide of Ammonia — Hydrochlorate or Muriate of Ammonia — Oxalate of Ammonia— Salt of Brucia — Iodo-disulphate of Quinine — Borax, or Bi-borate of Soda — Boracic Acid — Sulphate of Magnesia — Ammonio- Phosphate of Magnesia — Uric Acid, or Lithic Acid — Nitrate of Potash, or Nitre, Saltpetre — Salicine — Nitrate of Silver

PAGE

OBJECTS FOR THE MICROSCOPE.

Introduction

c< The microscope is an optical instrument by means of which we are enabled to see objects or parts of objects too minute to be seen with the naked eye; the name being taken from two Greek words, fiiKpov (mikron), a little thing , and (tko7T8uj (skopeo), I look at.” — Lardner.

ON THE USE OF THE MICROSCOPE.

Although a minute description of the construction of the microscope would be out of place in this small work, and involve more of the science of optics than could be understood without diagrams and much knowledge of the laws of light, yet it will be useful to give a few hints on the practical management of a newly-purchased instrument.

Assuming the student to be desirous of obtaining an efficient instrument at a moderate cost, he cannot do better than procure what is ordinarily termed a student's microscope, which may be obtained from £3 3<s. to £5 5s.

The following makers supply well-finished microscopes at low prices: — Amadio, 7, Throgmorton Street; Baker, 243, High Holborn ; Highley, 7 0, Dean Street ; Horne and Thornthwaite, 121, Newgate Street; Ladd, 11, Beak Street, Regent Street ; Newton, 3, Fleet Street ; Pellischer, 88, New Bond Street ; Smith, Beck, and Beck, 6, Coleman Street ; Wood, 74, Cheapside.

It is a difficult and delicate matter to treat this recommending of a microscope — the makers are every year improv-

l

ON THE USE OF ing and perfecting their instruments. Those who can afford one of Powell and Lealand's, Ross's, Dallmeyer's, or Smith and Beck's, will in truth have all the assistance that art of man can give to our natural eyesight. But for those who take up natural history as a recreative science, and have not a large sum at command, I would specially advise the choice of an instrument in the first instance of such a make that the various powers and appliances can be afterwards fitted as the student advances in the study.

The small binocular made by Messrs. H. and W. Crouch, of Regent's Canal Docks, cannot be too highly praised, and of which some short account may be acceptable.

* ; Recreative Science/ 3 vols London.

It had long been a desiderata with microscopists to obtain the advantage of binocular vision with stereoscopic effect. Mr. P. H.Wenhamwas the successful adapter of the stereoscopic principle to the microscope, which the following extract from ' Recreative Science'* will clearly explain : The result is obtained by the introduction of a small, but very accurately formed, double reflecting prism, immediately above the object-glass, so as to intercept half the rays of light which pass through it. Pig. 1 will explain the principle : — a is the body of an ordinary microscope j at b a square hole is cut, through which the prism c is made to slide so far that its edge will just reach the central line of the objective,

. fjap. 4to, Groombridge and Sons,

THE MICROSCOPE.

and should be made to draw back so as to clear the aperture altogether, when the tube a acts as a single microscope. When the prism is thrust in, it collects a portion of the rays, and reflects them to the opposite side of the tube, where an opening is made large enough to allow them to pass through, into the supplementary body, e, which in size corresponds to the main tube; the remainder of the rays pass uninterruptedly up the principal body.

Fig. 2 is an enlarged outline of the prism. Let e e be a ray of light having passed through the object-glass and entering the prism at right angles at the point f ; passing on, it is intercepted by the surface a b, which being inclined within the angle of total reflection, the ray is reflected towards h, from which point it is again reflected in the direction required. If the prism be correctly made, and of the smallest size possible for admitting the pencil, the difference between the direct and reflected image is scarcely observable ; a faulty prism therefore can be easily detected.

The adjustment for difference of distance between the eyes is effected by means of the draw tubes ; if they are at the utmost limit of proximity when close in, by drawing them out they can be made to suit every position of eye^ sight. This is very conveniently done by means of a rack and pinion movement, as shown in Fig. 3.

The opaque principle of illumination should be used in all cases where possible, as this gives to objects a more natural appearance. The effect upon looking through a binocular microscope for the first time is very striking; many peculiarities are instantly presented to the eye, which, with a single body, would be observed with difficulty. The

ON THE USE OF instrument figured is one of those exhibited by Messrs. Crouch at the Manchester Exhibition of Science and Art.

The advantage of the binocular is chiefly in the rest it gives the eyes, which have no unequal and unnatural strain.

The field of vision is extended, and objects are seen in relief, round, life-like, and distinct. The joints of insects are seen in a wonderful manner, the ball and socket joints and hinge joints, if well prepared, are now perfectly realised; the hairs of plants and animals are seen in their true position ; suckers, especially those on the foot of Dyticus, present themselves in the erect attitude of life, and Diatoms

THE MICROSCOPE.

mounted dry on a black disc exhibit their form and markings, as if the more elaborate parabolic reflector was beneath. To test this, obtain a slide of Heliopelta,or of Isthmia enervis, or of Arachnoidiscus, which will show the advantage of the binocular with a very moderate power.

Fossil foraminated shells (Barbadoes).

Spicules of gorgonia.

Section of Rush.

Capsules of Moss.

Any of these will answer the same purpose.

Whilst adding a few thoughts to this introductory chapter, let me answer one or two questions not unfrequently put to me.

How much does this microscope magnify ?

That is, a small binocular with simple eye-piece, and three object-glasses of two-inch, one-inch, and half-inch focus. The scale of magnifying power varies with different makers; but if I give my own microscope as an example, it will help to make others understood.

The two-inch object-glass, which has an angular aperture of 15°, will magnify twenty-five diameters, or 400 times superficial measurement.

The one-inch object-glass has usually about 23° angular aperture, magnifies fifty to sixty diameters, or 960 times superficial measurement.

The half-inch object-glass has an angular aperture of 60° or 65°, and consequently magnifies 120 diameters, or 1920 times superficial measurement.

Again, I am asked, What is the angle of aperture ?

This cannot here be explained beyond the brief statement, that it is the angle made by two lines from opposite sides of the aperture of the object-glass with the point of the focus of the lens . A diagram is necessary to make this quite clear.

The two-inch object-glass requires a certain distance, as at a, to bring the object under examination into distinctness or focus.

The inch, half-inch, quarter-inch glasses, require nearer and nearer approach to the object for the same purpose.

ON THE USE OF

The angles so made by the dotted lines are measured by a graduated semicircle of 180°, under peculiar management of light well known by opticians, but beyond our present inquiry ; and denote the number of extreme lateral rays which the object-glass admits.

The larger the angle the greater are the number of rays admitted and the more brilliantly the object is illuminated, the greater, consequently, is the defining power. Experiment has shown that obliquity of light is needful for the perception of the most delicate markings, and that an outline visible with an object-glass of small angular aperture admitting but few oblique rays, as in fig. 1, would be filled up with lines of beauty, and striae of inconceivable delicacy under an object-glass of large aperture, as fig. 3, which gives it an oblique illumination.

The markings on butterfly scales and the valves of Diatomaceae will illustrate this.

Again, it is asked, What is that particular fault which object-glasses by inferior makers are liable to, called spherical aberration ? It is when objects at the circumference of the field are not in focus at the same time as those in the centre, or when part of a single object fades away towards the circumference.

Another fault is chromatic aberration, when coloured fringes surround the object under examination, whereas an achromatic lens shows a clear colourless field and a purely bright object.

THE MICROSCOPE.

Defining power, not the magnifying power, is the thing to care for ; we want to see the real structure of an object, not an exaggerated representation; and those are the best glasses which transmit clear light, give a perfectly flat field, and by which we see sharp distinct lines in the object we are investigating.

I will but add a few practical hints on the management of the microscope : —

Do not imagine that an expensive apparatus is necessary. The greatest discoveries have been made with the simplest instruments.

Have good object-glasses, and do not waste money on an elaborate stage.

Use low powers in preference to high ones, unless absolutely necessary ; and, remember, we do not want objects magnified so much as we want them defined . A clearlydefining low power is the best working glass.

A few simple tools will be sufficient for all purposes of dissection and examination, viz. —

Slides of glass.

Circles and squares of thin glass.

A pair of forceps.

A lancet.

A few needles, fixed in handles. Split one end of a match, and tie the needle in with some waxed silk.

Two or three camel-hair pencils.

Six watch glasses.

These are all that are absolutely necessary for daily study.

FOR MOUNTING OBJECTS.

This need not be a difficult or expensive process ; but to succeed wTith insect preparations time and experience are essential. The easiest beginning is with vegetable specimens— cuticles, pollen, &c., — and with palates wThich are mounted in fluid.

You must have a turn-table, price 65. to 8 s., and make a cell on each glass slide you mean to use, with gold size

ON THE USE OP or Brunswick black. It is better to see this done than to read the best description of “ how to do it.” A small bottle of gold size or Brunswick black costs 6 d.

Make a solution of salt and water ; be careful that it is very clean, and better use distilled or filtered water — five grains of salt to one ounce of water. This is the best preservative for palates .

Pure glycerine — a small bottle, 1$. This is excellent for leaves of moss and cuticles ; but they also mount very well and more easily in Mr. Topping's liquid : one part of acetate of alumina to four parts of distilled water.

Let your cells be quite dry ; it is better to make a dozen or more at once and keep them by you. When required, fix the slide upon the turn-table, put a drop of the liquid in the cell with a camel-hair pencil, then lay the object in it. Have a thin glass cover ready, and let it gently fall over the cell. Remove the superfluous moisture with a little sponge or blotting paper ; and then, with a steady hand, take a brushful of Brunswick black, make the revolving table run round quickly, and, touching the edge of the cell, a circle of the varnish will safely fix it. Let the varnish be thin, and the circle also; for it dries better, and there is less danger of its running into the cell-contents. The next day go over it again, making the circle thicker and wider.

P on MOUNTING IN BALSAM.

Have a bottle of clear, pure Canada balsam — it costs 1$.

A little spirit of turpentine, 3 d.

Spirits of wine, one ounce, Is.

A brass table or tripod.

A spirit lamp.

Solution of caustic potash.

The use of balsam in preparing insect parts is not only to preserve, but to show the structure of the object. When properly applied, it enters into the minutest parts, displacing the air, and rendering the external tegument — hairs, spines, or suckers — perfectly transparent.

Bor instance, many young students, anxious to see the

THE MICEOSCOPE.

leg of a fly, or of a beetle, clip it off, and put it under the microscope. They are somewhat disappointed at seeing indistinctly a row of black joints, and nothing more.

Let that leg be first soaked for a few days in a little potash and water, to soften it and dissolve the internal substance; then washed in clean water and dried; then soaked for a few minutes in turpentine, and finally mounted in balsam : every joint will be clear, every hair visible, the pulvillus transparent, and the structure admirably displayed.

The same results are obtained with the eyes, tongues, and wings of all insects.

The actual mounting is a matter of experience : to keep out air bubbles is the great and only difficulty.

Place a slide on the brass table, over the spirit lamp, and when heated moderately put a drop of balsam in the centre of it ; let this also become warm, but not very hot, and then lay the prepared object in it. As bubbles arise, skim them off with a needle, and take care that the balsam does not boil, or your specimen is lost ; — it will be full of obstinate air bubbles, irrevocably fixed in the tissue. When it looks clear, examine under the microscope, and if all right replace it on the table, and having previously warmed a thin glass cover, let it drop gently over the object.

Dry it on the mantelpiece, or a stone slab, and then clean the slide by scraping off the balsam and washing it with a little turpentine; or soda and water will clean it nicely; only if it is left in the solution, it will unsettle the balsam.

Try experiments for yourself, and do not be discouraged by a great many failures; neither be satisfied with bad mounting, half-prepared objects, and untidy slides.

PART I.

OBJECTS FROM THE VEGETABLE KINGDOM.

€f Search out the wisdom of Nature, — there is depth in all her doings. She hath on a mighty scale a general use for all things ;