and Laboratory Methods. 



1401 



high-power work, which for depth of focus, magnification, and extent of field, 

 cannot be reproduced with cheap or improvised apparatus. 



If, for instance, an ordinary microscope is used with an ordinary camera, 

 none of the figures here shown can be duplicated, no matter how good the lenses 

 may be, for to produce any power here given a higher objective, with a narrower 

 field and less deep focus, would be indispensable, and this would sacrifice part 

 of the field entirely, and the focus over the part retained. 



One reason why photomicrography has not hitherto succeeded better, is that 

 cheap apparatus, scraped together from a microscopic and a photographic outfit, 

 has been recommended. This cheap apparatus was always the most expensive 



Fig. 3. — Cells from onion rootlet ; iron-haematoxylin stain, x 1500. 



to be had, for the reason that the time consumed in getting ready for and making 

 a successful exposure costs, in the end, more than the investment for a correct 

 outfit. 



In the second place, the results, for reasons above given, were never valuable 

 except in the case of slides so perfectly prepared that they had to be the best of 

 an expert microscopist's work. I again and again concluded, while using these 

 makeshifts, that histological slides could not be successfully photographed. I 

 thought photomicrography was an art, the usefulness of which was confined to 

 the resolving of lines on diatoms, and reproducing the silhouettes of bacteria so 

 prepared that the contrast was sharp and the field flat. 



The cheap way to make successful photomicrographs is to have a complete 



