Evenings at the Microscope; or, Researches among the Minuter Organs and Forms of Animal Life
Evenings at the Microscope; or, Researches among the Minuter Organs and Forms of Animal Life
By Philip Henry Gosse, F.R.S.
A new edition, revised and annotated.
Published under the direction of the Committee of General Literature and Education, appointed by the Society for Promoting Christian Knowledge.
London: Society for Promoting Christian Knowledge.
New York: E. & J. B. Young & Co.
1884
PREFACE.
To open the path to the myriad wonders of creation, which, altogether unseen by the unassisted eye, are made cognisable to sight by the aid of the microscope, is the aim and scope of this volume. Great and gorgeous as is the display of Divine power and wisdom in the things that are seen of all, it may safely be affirmed that a far more extensive prospect of these glories lay unheeded and unknown, till the optician's art revealed it. Like the work of some mighty genie of Oriental fable, the brazen tube is the key which unlocks a world of wonder and beauty before invisible, which one who has once gazed upon it can never forget, and never cease to admire.
This volume contains but a gleaning : the author has swept rapidly across the vast field of marvels, snatching up a gem here and there, and culling one and another of the brilliant blossoms of this flowery region, to weave a specimen chaplet, a sample coronal, which may tell of the good things behind. Yet the selection has been so made as to leave untouched no considerable area of the great field of Zoology which is under the control of the microscope ; so that the student who shall have verified for himself the observations here detailed, will be no longer a tyro in microscopic science, and will be well prepared to extend his independent researches, without any other limit than that which the finite, though vast, sphere of study itself presents to him.
The staple of the work now offered to the public consists of original observation. The author is far from thinking lightly of the labours of others in this ample field ; but still, it is true that, respecting very many of the subjects that came under his notice, he found, in endeavouring to reproduce and verify published statements, so much perplexity and difficulty that he was thrown back upon himself and nature, compelled to observe de novo, and to set down simply what he himself could see. The everaccumulating stock of observed and recorded facts is the common property of science ; and the author has not scrupled to reproduce, to amplify, or to abridge his own observations which have already appeared in his published works and scientific memoirs, as freely as he would have cited those of any other observer in which he had confidence, and which were germane to his purpose. Yet, in almost all cases, the observations so used have been subjected to renewed scrutiny, and have been verified afresh, or corrected where found defective.
In order to relieve as much as possible the dryness of technical description, a colloquial and familiar style has been given to the work ; which has been thrown into the form of a series of imaginary conversaziones, or microscopical soirees, in which the author is supposed to act as the provider of scientific entertainment and instruction to a circle of friends. It is proper to add, however, that the precision essential
PREFACE.
to science has never been consciously sacrificed. A master may be easy and familiar without being loose or vague.
A considerable amount of information will be found incidentally scattered throughout the work on microscopic manipulation,—the selecting, securing, ;—an and preparing of the objects for examination important matter, and one which presents a good deal of practical difficulty to the beginner. Not a little help will be afforded to him, also, on the power to observe and to discriminate what he has under his eye. In almost every instance, the objects selected for illustration are common things, such as any one placed in tolerably favourable circumstances, with access to sea-shore and country-side, may reasonably expect to meet with in a twelvemonth/ s round of research.
The pictorial illustrations are almost co- extensive with the descriptions ; they are one hundred and thirteen in number; all, with the exception of eighteen,* productions of the author's own pencil, the great majority having been drawn on the wood direct from the microscope, at the same time as the respective descriptions were written. He ventures to hope that they will be found accurate delineations of the objects represented.
Torquay, February, 1859.
- The subjects on pp. 43, 48, 98, 100, and 151, have been copied, under the courteous permission of the publisher, from Dr. Carpenter's valuable work, " The Microscope, and its Kevelations." (Churchill, London.)
Preface to the Present Edition
In preparing a new edition of this Work for the press, every page has passed under the Author’s eye, and has been examined with earnest care. A very large portion of it consisting of his own original researches, there was little room for alteration; but new facts, interesting in themselves, and germane to the subjects herein treated, which have been recorded since, he has used to enrich the work. These have been uniformly added in the shape of marginal notes; leaving the text untouched, a reflection of Microscopical Science a quarter of a century ago.
P. H. G.
Torquay, May, 1884
Contents
- I. Hairs, Feathers, and Scales — 1
- II. Blood — 25
- III. Mollusca: their Shells, Tongues, Eyes, and Ears — 39
- IV. Sea-mats and Shelly Corallines — 59
- V. Insects: Wings and their Appendages — 70
- VI. Insects: their Breathing Organs — 93
- VII. Insects: their Feet — 109
- VIII. Insects: their Stings and Ovipositors — 125
- IX. Insects: their Mouths — 138
Contents
- X. Insects: their Ears and Eyes — 158
- XI. Crabs and Shrimps — 171
- XII. Barnacles — 191
- XIII. Spiders and Mites — 203
- XIV. Wheel-bearers — 223
- XV. Worms — 258
- XVI. Sea-urchins and Sea-cucumbers — 276
- XVII. Jelly-fishes — 307
- XVIII. Zoophytes — 325
- XIX. Sea-Anemones: their Weapons — 355
- XX. Protozoa and Sponges — 376
- XXI. Infusoria — 389
LIST OF ILLUSTRATIONS.
Page Human Hair Hog's Bristles Fibre of Sheep's wool . Hair of Cat . Hairs of Mole Hair of Sable Hair of Mouse 10 Tip of Small Hair of Mouse 11 Hair of Bat . II Hair of Indian Bat 12 Tip of Hair of Dermestes 11 Barb of Clothing Feather of
Fowl Barb from Goose-quill . 16 Scales of Perch . Scales of Gold-fish Scale of Flounder Scales of Pike Spicula of Gold-fish's Scale Blood-disks Circulation in Frog's Foot 32 Perophora . 33 Cuttle-shell . 41 Section of Nacre from Pearl
Oyster 43 Toogue of Trochus 48 Structure of Eye of Snail 54 Leafy Sea-mat 62 Doubling and Hooks in a
Bee's Wing 74 Scales on a Gnat's Wing 75 Bristle-tail . 76 Scale of Bristle-tail
Page 2 Battledore scale of Polyom 5 matus Alexis . 80 7 Fringed Scale of Pieris 81 8 Scales of Diamond-beetle 83 9 Air-pipe of Fly . 95 9 Spiracle of Fly 98
Spiracle of Leather-coat 99
Spiracle of Cockchafer-grub 100
Grub of Chameleon-fly 102
Foot of Fly . 116
Foot of Water-beetle . 118
Sting of Bee 127 15 Gall-fly, and Mechanism of
Ovipositor 128 17 Outer Saw of Saw-fly . 133 19 Inner Saw of Saw-fly . 134 21 Mouth of Beetle . 140 23 Jaws of Bee 142 21 Lancets of Female Gnat 150 28 Tongue of Blow-fly 151
Sucker of Butterfly 156
Antenna of Cockchafer 162
Antenna of Oak Egger Moth 164
Ear of Crab . 172
Daphnia Cypris.... 179 181
Zoea of Shore-crab 183
Second Stage of Shore-crab 185
Third Stage of Shore- crab 187
Adult Shore-crab 188
Hand of Barnacle 193
Young of Barnacle 197
Fang of Spider . , 206 Eyes of Spider Claws of Spider . Head of Cheese-mite .
Chapter I. Hairs, Feathers, and Scales
Not many years ago an eminent microscopist received a communication inquiring whether, if a minute portion of dried skin were submitted to him, he could determine it to be human skin or not. He replied that he thought he could. Accordingly a very minute fragment was forwarded to him, somewhat resembling what might be torn from the surface of an old trunk, with all the hair rubbed off.
The professor brought his microscope to bear upon it, and presently found some fine hairs scattered over the surface ; which, after carefully examining them, he pronounced with confidence to be human hairs, and such as grew on the naked parts of the body ; and declared the person who had owned them to have been of a fair complexion.
This was a very interesting decision, because the fragment of skin was taken from the door of an old church in Yorkshire ;* in the vicinity of which a tradition is
- I am writing from memory, having no means of referring- to the original record, which will be found in the first (or second) volume of the "Transactions of the Microscopical Society " of London. The general facts, however, may be depended on. B preserved, that, about a thousand years ago, a Danish robber had violated this church, and, having been taken, had been condemned to be flayed, and his skin nailed to the church-door, as a terror to evil-doers. The action of the weather and other causes had long ago removed all traces of the stretched and dried skin, except that, from under the edges of the broad-headed nails with which the door was studded, fragments still peeped out. It was one of those atoms, obtained by drawing one of the old nails, that was now subjected to microscopical scrutiny ; and it was interesting to find that the wondershowing tube could confirm the tradition with the utmost certainty ; not only in the general fact, that it was really the skin of man, but in the special fact of the race to which that man belonged, viz., one with fair complexion and light hair, such as the Danes are well known to possess.
It is evident from this anecdote that the human hair presents characters which are so indelible that centuries of exposure do not avail to obliterate them, and which readily distinguish it from the hair of any other creature. Let us then begin our evening's entertainment by an examination of a human hair, and a comparison of it with that which belongs to various animals. Here, then, is a hair from my own head. I cut oft" about half-an-inch of its length, and, laying it between two plates of glass, put it upon the stage of the microscope. I now apply a power of 600 diameters ; that is, the apparent increase of thickness is the same as if six hundred of these hairs were placed side by side. Now, with this eye-piece micrometer, we will first of all measure its diameter. You see, crossing the bright circular field HVMAN HAIR. of view, a semi-pellucid cylindrical object • that is the hair. You see also a number of fine
<!-- pandi-media-anchor:figure-p16-o9-a052547fca7a4998 -->lines drawn parallel to each other, exactly like those on an ivory rule or scale, with every fifth line longer than the rest, and every tenth longer still. This is the micrometer, or scale by which we measure objects; and the difference in the length of the lines, you will readily guess, is merely a device to facilitate the counting of them. By moving the stage up or down, or to either side, we easily bring the hair exactly into the centre of the field ; and now, by adjusting the eye-piece, we make the scale to lie directly across the hair, at right angles with its length. Thus we see that its diameter covers just thirty of the fine lines ; and as, with this magnifying power, each line represents 1-1 0,000th of an inch, the hair is 30- 10,000ths, = —^1x1 of an inch, in diameter.