MODERN REVELATIONS OF THE MICROSCOPE. 41 



to guard against them, the more completely will it be found that 

 an essential agreement exists among them all, in regard to the 

 facts which they record. And although the influence of precon- 

 ceived theories still too greatly modifies, in the minds of some, the 

 descriptions they profess to give of the facts actually presented to 

 their visual sense, yet on the whole it is remarkable to what a 

 unity of doctrine the best Microscopists of all countries are con- 

 verging, in regard to all such subjects of this kind of inquiry, as 

 have been studied by them with adequate care and under simi- 

 lar -conditions. Hence it is neither fair to charge upon the 

 Microscopists of the present day the errors of their predecessors ; 

 nor is it just to lay to the account of the instrument, what 

 entirely proceeds from the fault of the observer, in recording, not 

 what he sees in it, but what he fancies he can see. 



It was at the commencement of the second quarter of the 

 present century, that the principle of Achromatic correction, which 

 had long before been applied to the Telescope, was first brought 

 into efficient operation in the construction of the Microscope ; 

 for although its theoretical possibility was well known, insupera- 

 ble difficulties were believed to exist in its practical application. 

 The nature of this most important improvement will be explained 

 in its proper place (Chap. I) ; and at present it will be sufficient 

 to say, that within eight or ten years from the date of its 

 first introduction, the character of the Microscope had been in 

 effect so completely transformed, that it became an altogether 

 new instrument; and from being considered but little better 

 than a scientific toy, it soon acquired the deserved reputation of 

 being one of the most perfect instruments ever devised by Art 

 for the investigation of l>rature. To this reputation it has a still 

 greater claim at the present time ; and though it would be ha- 

 zardous to deny the possibility of any further improvement, yet 

 the statements of theorists as to what may be accomplished, are 

 so nearly equalled by what has been effected, that little room for 

 improvement can be considered to remain, unless an entirely 

 new theory shall be devised, which shall create a new set of 

 possibilities. 



Neither Botanists or Zoologists, Anatomists or Physiologists,' 

 were slow to avail themselves of the means of perfecting and ex- 

 tending their knowledge, thus unexpectedly put into their hands ; 

 and the records of Scientific Societies, and the pages of Scientific 

 Journals, have ever since teemed, like the early Transactions of 

 the Royal Society, with discoveries made by its instrumentality. 

 All really philosophic inquirers soon came to feel, how vastly 

 the use of the improved Microscope must add to their insight 

 into every department of Organic IJature ; and numbers forth- 

 with applied themselves diligently to the labor of investigation. 

 Old lines of research, which had been abandoned as unlikely to 

 lead to any satisfactory issue, were taken up again with the con- 

 fident expectation of success, which the result has shown to have. 



