The history of the microscope, like that of many other useful human inventions, has been a chequered one. When first brought into use at the end of the seventeenth and the beginning of the eighteenth century extravagant expectations were formed of its value—expectations which were almost justified by the discoveries of Swammerdam, Hooke, Leeuwenhoek, and others. It failed, however, to realise these brilliant hopes, and we find the science of observation progressing rapidly from the middle of the eighteenth to the beginning of the nineteenth century without the aid of the microscope. Linnaeus, the great presiding genius of natural history at this period, had put his ban upon this instrument, and publicly announced bis opinion of its worthlessness in the pursuits of the naturalist. It, however, maintained its position in the toy-shops, and though disregarded by the man of science, it was a successful means of exciting the wonder of the ignorant in the hands of the mountebank. Even after the improvements of the microscope in the present century by Brewster, Lister, and others, which made it once more an instrument of observation, and the discoveries of Brown, Ehrenberg, Müller, and their contemporaries, it has not lost its hold on the public mind as a source of wonder, and a toy with which to pass away hours that would otherwise be found wearisome enough. We would not on this account propose a classification of those who possess microscopes into those who use them as toys and those who use them as philosophical instruments. It is certain, however, that the two classes exist and they probably run one into the other at many points, and we only allude to the subject here by way of warning to those who use or write upon the microscope to avoid the tendency to regard it as a mere instrument of amusement. The simplest combination of lenses that can be bought at a toy-shop may be made a means of instruction to the children for whom they are made. The microscope is, in fact, but an instrument or tool, and in this respect is like all others by the use of which certain ends can be attained and objects effected which could not be without its employment. As cutting with a sharp instrument is better than tearing with the nails, so vision with the microscope is better than with the naked eye. Its use is, therefore, as extensive as that of the organ which it assists, and it cannot be regarded as the property of one branch of science more than another. It is true that in revealing the intricate structure of organized beings it has been more extensively employed by the physiologist and naturalist than by other scientific inquirers, but it cannot be claimed exclusively for histology or any other branch of science. But whatever may be the department of inquiry in which this important instrument is employed, the general principle of its construction and use are the same, hence the demand for books treating of its structure, and explaining the manner of its use and application. Of the various treatises that have been devoted to this subject in the European languages, we have no hesitation in pronouncing that by Professor Quekett as far the best, and we hope in our next number to have an opportunity of noticing the second edition of this excellent work. Still we have always regarded Mr. Quekett’s work as too minute and extended, as well as too expensive, to serve the purposes of those who only want an explanation of the instrument and a few plain directions for its use. The little work published in America by Dr. Wythes in size and price is evidently more adapted for general use. Its plan and contents are so evidently-founded upon the work of Mr. Quekett that we wonder the author did not at once acknowledge how largely he is indebted to that gentleman’s labours. It is one of the grievances that literary men have to complain of in this country, that their works are reprinted in America without their obtaining any profit from the wide sale they meet with in that country, and the least they have to expect is, when their works are reprinted or extensively drawn upon, that the debt be acknowledged.
As an instance of how much Dr. Wythes is indebted to the English professor, we would quote the chapter on Test-objects, which is scarcely more than an abstract of the chapter on the same subject in Mr. Quekett’s book, and in which no pains have been taken by an alteration of expression to conceal the source of the information. The plates illustrative of this subject are also copied from Mr. Quekett’s work, as well as many others.
Although Dr. Wythes’ work is intended for all who use the microscope, it is very evident that his own acquaintance with this instrument has been almost exclusively confined to animal tissues. Thus, speaking of the “circulation in plants termed cyclosis,” he says, “It can be observed in all plants in which the circulating fluid contains particles of a different refractive power or intensity, and the cellules are of sufficient size and transparency. Hence all lactescent plants, or those having a milky juice, with the other conditions, exhibit this phenomenon.” He has here confounded the general movement of the sap witnessed in lactescent plants with cyclosis. Again, in a chapter somewhat singularly called the “celldoctrine of physiology,” in speaking of the development of cells within other cells, he says, “each granule of the nucleus has the power of developing a cell and without any allusion to this as a controverted opinion, or to any other form of celldevelopment, he leaves the subject. It would perhaps be better in works of this kind that all physiological views and general principles arising out of the investigation of particular structures should be omitted. All that is required is a reference to the various classes of objects in which the microscope is found of advantage, and directions as to the best methods of examining such objects. In the present instance we find no directions given as to the best way of exhibiting the cyto-blast or the objects best fitted for showing it. Another omission in this book of more importance is the entire absence of any allusion to the use of re-agents in the examination of animal and vegetable tissues. The aid of chemistry has become so important in distinguishing certain tissues under the microscope, that too much stress can hardly be laid upon it in any directions for its use.
The work is illustrated with a great number of wood-cuts ; some of those of microscopic objects are very coarsely done. This is a pity, as too great pains cannot be taken in making evident in drawing those distinctions which are evident with the microscope. The wood-cuts, for instance, of the caudate cells, in figs. 36, 40, 41, and 42, are not sufficiently different to lead a young microscopist to the belief that by their means a distinction may be made out between an innocuous and a malignant tumour. We are sorry to have to find so much fault with this book, but it contains the elements of a useful volume, and, if we may judge from its sale in this country, the present edition is likely soon to be sold off, and to afford Dr. Wythes an opportunity of correcting its errors, acknowledging his debts, and extending his work in those directions in which it is most deficient.
