195 



VviJ 



On the Critical Employment of the Microscope for 

 Ordinary Working Purposes. 



By a. a. Merlin, F.R.M.S. 



{Read Noiiemher loth, 1901.) 



As a microscopist of over twenty years' experience, I trust 

 that it may not be considered presumptuous on my part to offer 

 a few remarks on the subject of " critical " microscopy, in the 

 hope that they may be of some interest to the younger members of 

 our Club. An apology is perhaps the more necessary in view 

 of the fact that the opening chapters of the last two editions of 

 " Carpenter " contain a most lucid and admirable exposition 

 of the whole principles of microscopical manipulation, and explain 

 at length the conditions under which the best results are alone 

 attainable. Now, as this work is in the hands of the great 

 majority of British microscopists, by whom its authoritative 

 character is generally admitted, one would naturally infer that 

 its students would endeavour to carry out its clearly-explained 

 precepts by applying them to their own several branches of 

 inquiry, and that once having done so, they would not fail to 

 appreciate the enormous advantage of such critical methods 

 of research as compared with the happy-go-lucky, rough- 

 and-ready systems still so zealously inculcated in many medical 

 schools. 



But whatever the reason may be, it is sufficiently evident to 

 the observant visitor at microscopical exhibitions and soirees that 

 a large number of the specimens there shown, although most 

 beautifully and carefully prepared and mounted by their 

 exhibitors, are optically arranged with a total disregard of the 



