The Microscope. Its History, Construction, and Application 15th ed. / Being a familiar introduction to the use of the instrument, and the study of microscopical science

by Jabez Hogg

PREFACE TO THE FIFTEENTH EDITION.

The First Edition of this work appeared in 1854, a time in the history of the Microscope when the instrument, as an aid to original scientific research, may be said to have been in its infancy. Then certainly it was seldom employed in the laboratory or the medical schools. Now, however, as I anticipated, it has asserted its proper position, and has at length become one of the most important auxiliaries to science, and a direct incentive to original work, while it has doubtless exercised considerable influence over the student’s power of observation, and materially assisted in his studies, let his ultimate object and pursuits be what they may.

The greater use made of the Microscope has likewise conferred benefits of untold value upon the arts and industries of the country, thereby adding to the national prosperity in ways as manifold as unique. The Microscope has also proved of immense value in the promotion of the health of the community, and the art and science of healing, since the theory of medicine has become a science, resting on the minute microscopical examination of animal tissues.

The work of research in the sister sciences and by other methods has, during the last decade, received a corresponding impetus, while it has undoubtedly tended towards elaboration and specialisation in all departments. In consequence, the progress of microscopical science has become more dependent upon the specialist for gaining accurate knowledge and for certain important details seen to be branching out in many directions. There never was a time when the instrument was so constantly and generally resorted to and with so much confidence and advantage, as the present. It has shown itself equal to the task imposed—that of teaching the eye to see things that are new, and also, what is perhaps of more importance, to perceive things which had been entirely overlooked. The older defects, perhaps, arose from two causes; the want of more careful training of the organ of vision, and the want of sufficient power and precision in the optical part of the Microscope itself. Both of these obstacles have been to a considerable extent removed, and all educational systems are looked upon as incomplete without a knowledge of the Microscope.

A step has already been taken in another direction, that of furnishing special forms of instruments, better adapted to the uses to which they will hereafter be put, and purposely designed for chemical and analytical processes, for petrological pursuits, the geometrical measurement of crystals, for special work in connection with manufacturing industries, for the dairyman, and the farmer. For the detection of adulterations—that of butter, for example—a newer form of instrument has been devised, namely, a “Butro-refractometer,” by the help of which any adulteration of this universal article of diet will at once be revealed. The form of instrument upon which the optician has expended a greater amount of skill than perhaps on any other is the Bacteriological Microscope, as may be inferred from the larger space I have devoted to this important adjunct, since by original research, there can be no doubt a still greater future is in store for science in this special department of microscopy. But perfect success in this direction remains very much with the practical optician, and the further improvements made in the optical part of the instrument, since it is admitted that the highest theoretical perfection has not yet been reached.

It is a commonplace remark that every question solved is a step towards new problems waiting solution. It is equally obvious that many difficulties must be encountered by every author who uses his best endeavours to supply a standard volume or even a fairly comprehensive text-book on the Microscope, one that will remain a sure guide for any lengthened period. Such a success I regard as scarcely possible. I may, however, notice that my earlier work has met with a great amount of appreciation, and its utility acknowledged in the past by a demand almost unprecedented, edition after edition being called for.

It is hardly necessary to add that my task has been accomplished with an earnest desire to assist in diffusing a love for an instrument which has been my constant companion for upwards of sixty years.[1] Moreover, I have a firm conviction of the real utility of the Microscope in the work of education, its practical value in many branches of science, art, and manufacturing industries. These are my chief reasons for applying myself once more to the task of revision, rewriting, and rearranging and bringing this book as far as possible into line with the knowledge gained in chemical pathology and bacteriology.

It will be noticed that in the first part, my subjects have as far as possible been treated from a historical point of view. This method has enabled me to affix dates of introduction of special inventions and improvements made in the instrument and its appliances. The enlargement of my pages has enabled me to devote more space to bacteriological processes, and by the further addition of plates and several hundred illustrations to more fully elucidate the subject matter of my text. In an Appendix I have introduced a selection of “Formulæ and Methods” of staining, mounting, etc., also tables of the “Metrical System,” now in general use in the laboratory; together with comparative thermometric values, all of which I trust may prove of service to the student.

Before bringing these few prefatory remarks to a close, a pleasing duty devolves upon me—that of tendering my thanks for cordial aid received from Professor Dr. Edgar Crookshank in dealing with his special subject, Bacteriology. From his valuable “Text-Book on Bacteriology” I have extracted much useful matter. I am equally indebted to Professor Marshall Ward, F.R.S., Cambridge, for much information on “Economic Botany,” and the great advances made in the knowledge of the uses of plants, and the industrial value of bacteria in particular. My acknowledgments are also due to the Messrs. Warne for many illustrations placed at my disposal, and for useful facts derived from their “Royal Natural History.” It will, however, be seen that the results of a large amount of independent observation have been consigned to my pages. As the references show, recourse has been had to original sources for trustworthy, reliable information on many subjects. These are constantly, almost daily, being added to, as is made manifest by the numerous periodical publications of the day devoted to this and kindred sciences; the foremost and most important among which is that almost exclusively given to microscopical science, “The Journal of the Royal Microscopical Society of London,” the perusal of which I commend to my readers.

London, July, 1898.