68 Proceedings. 
microscope have tried to employ photographs as a means of 
recording their observations. The advantages of doing so would 
clearly be very great. The question for the worker in science 
was, and still is, whether those advantages are worth the time 
and trouble necessary to obtain results good enough to be 
useful. : 
Twenty years ago this question was by common consent 
answered in the negative. Very beautiful photomicrographs 
were produced in those days, but they represented an expendi- 
ture of time and labour quite out of proportion to their scientific 
value. But since that date photography has been revolutionized 
by the general adoption of the dry-plate process. Great strides 
have also been made in the manufacture of microscopic lenses, 
and in the art of preparing and staining objects for microscopic 
observation. Apochromatic lenses have been constructed by 
the firm of Carl Zeiss in Jena, and by other opticians on their 
model. The microtome is generally used in botanical as well as 
in zoological laboratories. Photomicrography is now a com- 
paratively simple art, and the whole question of its use to the 
professional biologist is again open. 
In Bacteriology, indeed, photomicrographs are generally used. 
A few zoologists and botanists have photographed their prepara- 
tions, generally for class demonstration by means of the lantern. 
But the method is not yet naturalized in the biological 
laboratory. 
The advantages of the method are briefly these :—(1) the 
absence of personal bias in the picture produced by the camera; 
(2) the easy multiplication of prints; (3) the great ease with 
which photographs of two preparations can be compared with 
each other. These points are worth considering separately. 
Everyone who has worked with the microscope knows how 
difficult it is to keep an unprejudiced mind. It is possible to 
be perfectly honest in intention and yet to consistently mis- 
represent the facts, first to oneself and then to others. For 
this reason it is often of the greatest service to get an unbiassed 
opinion on a preparation—a “fresh eye” as is sometimes said. 
And for similar reasons the photograph of a familiar section is 
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