It is not many years since this invaluable instrument was regarded in the light of a costly toy; it is now the inseparable companion of the man of science. In the medical world, its utility and necessity are fully appreciated, even by those who formerly were slow to perceive its benefits; now, knowledge which could not be obtained even by the minutest dissection is acquired readily by its assistance, which has become as essential to the anatomist and pathologist as are the scalpel and bedside observation. The smallest portion of a diseased structure, placed under a Microscope, will tell more in one minute to the experienced eye than could be ascertained by long examination of the mass of disease in the ordinary method. Microscopic agency, in thus assisting the medical man, contributes much to the alleviation of those multiplied “ills which flesh is heir to.” So fully impressed were the Council of the Royal College of Surgeons with the importance of the facts brought to light in a short space of time, that, in 1841, they determined to establish a Professorship of Histology, and to form a collection of preparations of the elementary tissues of both animals and vegetables, healthy and morbid, which should illustrate the value of microscopical investigations in physiology and medical science. From that time, histological anatomy deservedly became an important branch of the education of the medical student.
In the study of Vegetable Physiology, the Microscope is an indispensable instrument; it enables the student to trace the earliest forms of vegetable life, and the functions of the different tissues in the growth of plants. Valuable assistance is derived from its agency in the detection of adulterations. In the examination of flour, an article of so much importance to all, the Microscope enables us to judge of the size and shape of the starch-grains, their markings, their isolation and agglomeration, and thus to distinguish the starch-grains of one meal from those of another. It detects these and other ingredients, invisible to the naked eye, whether combined in atoms or aggregated in crystals, which adulterate our food, our drink, and our medicines. It discloses the lurking poison in the minute crystallisations which its solutions precipitate. “It tells the murderer that the blood which stains him is that of his brother, and not of the other life which he pretends to have taken; and as a witness against the criminal, it on one occasion appealed to the very sand on which he trod at midnight.”
The zoologist finds in the Microscope a necessary coadjutor. To the geologist it reveals, among a multiplicity of other facts, “that our large coal-beds are the ruins of a gigantic vegetation; and the vast limestone rocks, which are so abundant on the earth’s surface, are the catacombs of myriads of animal tribes, too minute to be perceived by the unaided vision.”
By “conducting the eye to the confines of the visible form,” the Microscope proves an effective auxiliary in defining the geometric properties of bodies. Its influence as an instrument of research upon the structure of bodies has been compared to that of the galvanic battery, in the hands of Davy, upon Chemistry. It detects the smallest structural difference, heretofore inappreciable, and, as an ally of Chemistry, enables us to discover the very small changes of form and colour effected by test-fluids upon solids; and dissects for us, so to speak, the most multiplex compounds. It opens out to the mind an extended and vast tract, opulent in wonders, rich in beauties, and boundless in extent.
The Microscope not only assists studies, and develops objects of profound interest, but also opens up innumerable sources of entertainment and amusement, in the ordinary conventional acceptation of these terms; disclosing to us peculiarities and attractions in abundance; impressing us with the wonderful and beautifully skilful adaptation of all parts of creation, and filling our minds with additional reverence and admiration for the beneficent and Almighty Creator.
The Author will conclude these prefatory observations with a few words in explanation of his arrangements, by way of dealing with the instrument and development of his subject. He has sought, in the volume that he now lays before the public, to point out and elucidate at once in a practical manner and in a popular style, the vast fund of utility and amusement which the Microscope affords, and has endeavoured to touch upon most of the interesting subjects for microscopic observation as fully as the restrictions of a limited space, and the nature of the succinct summary, would permit. To have dwelt upon each in complete detail would have necessitated the issue of many expensive volumes—and this would have entirely frustrated the aim which the writer had in view; he has, therefore, contented himself with the humble, but, he trusts, not useless, task of setting up a finger-post, so to say, to direct the inquirer into the wider road. In the section of the work devoted to the minuter portion of creation, he has ventured to dwell somewhat longer, in the belief that that department is more especially the province of the microscopist. He has arranged his topics under special headings, and in separate chapters, for the sake of perspicuity and precision; and has brought the ever-welcome aid of illustration to convey his explanatory remarks more vividly to the minds of his readers.
Finally, it is the Author’s hope that, by the instrumentality of this volume, he may possibly assist in bringing the Microscope, and its valuable and delightful studies, before the general public in a more familiar, compendious, and economical form than he found it at the period of its publication, so that, in these days of a diffused taste for reading and the spread of cheap publications, he may thus supply further exercise for the intellectual faculties; contribute to the additional amusement and instruction of the family circle, and aid the student of nature in investigating the wonderful and exquisite works of the Almighty. If it shall be the good fortune for this work, which is now confided with great diffidence to the consideration of the public, to succeed, in however slight a degree, in furthering this design, the Author will feel fully repaid for the amount of time and labour expended.
London, May, 1854.
CONTENTS.
| [PART I]. | |
|---|---|
| PAGE | |
| Early History of the Microscope | 1 |
| [CHAPTER I]. | |
| Light—Its Propagation—Refraction—Spherical and Chromatic Aberration—Human Eye—Formation of Images—Visual Angle—Abbé’s Theory of Microscopic Vision—Definition of Aperture—Numerical Aperture—Abbé’s Apertometer—Stereoscopic Binocular Vision | 12 |
| [CHAPTER II]. | |
| Simple and Compound Microscopes—Evolution of the Modern Achromatic Microscope—Improvements in the Modern Microscope: The Ross-Jackson, Powell and Lealand, Beck’s, Baker’s, Pillischer, Zeiss, Leitz, Watson’s, Van Heurck’s Edinburgh Students’, Swift’s, and Bacteriological | 72 |
| [CHAPTER III]. | |
| Applied Optics—Eye-pieces—Achromatic Objectives and Condensers—Magnifying Power of Eye-pieces and Objectives—Method of Employing the Condenser—Its Illumination Mirror—Accessories of the Microscope—Finders—Micrometers—Camera-Lucida—Microscope in Position for Drawing—Abbé’s Test-Plate—Micro-Photography—Polarisation of Light—The Micro-Spectroscope | 139 |
| [CHAPTER IV]. | |
| Practical Microscopy—Manipulation—Mode of Employing the Microscope—Working Accessories—Methods of Preparing, Hardening, Staining, and Section Cutting—Cutting Hard Structures—Injecting Apparatus, Material, etc., employed in Bacteriological Investigations—Warm Chambers and Incubators—Preparing, Mounting, Cementing, and Collecting Objects | 258 |
| [PART II]. | |
| [CHAPTER I]. | |
| Microscopic Forms of Life—Thallophytes, Pteridophyta, Phanerogamæ—Structure and Properties of the Cell—Pathogenic Fungi and Moulds—Parasitic Diseases of Plants, Man, and Animals—Industrial Uses of Fungi and Saccharomycetes—Desmidiaceæ and Diatomaceæ—Lichens, Mosses, Ferns, Flowering Plants | 353 |
| [CHAPTER II]. | |
| Sub-Kingdom Protozoa—Rhizopoda—Gromia and Foraminifera—Infusoria—Ciliata—Rotifera—Porifera—Sponges | 478 |
| [CHAPTER III]. | |
| Zoophytes—Cœlenterata—Medusæ—Corals—Hydrozoa—Mollusca—Annulosa—Worms—Entozoa—Annelida—Crustacea | 515 |
| [CHAPTER IV]. | |
| Arthropoda—Insecta—Arachnida—Acarina—Ixodidæ—Mites and Ticks | 583 |
| [CHAPTER V]. | |
| Vertebrata—Internal and External Structures | 633 |
| [CHAPTER VI]. | |
| The Mineral and Geological Kingdoms | 670 |
| [APPENDIX]. | |
| Dr. Mercer on Illumination, and Abbé’s Theory—Micro-Spectroscope—Formulæ, Methods, Cementing, Clearing, Hardening, and Mounting—Tables, Metric and Thermometric | 672 |
| [INDEX] | 691 |