20 PHOTO-MICROGRAPHS. 
microscopic object is suited for photography ; and 
those who imagine that it will be a very simple 
matter to make photographs of all the objects in 
their collection when they have provided them- 
selves with the necessary apparatus and have 
learned to develop a dry plate, are doomed to dis- 
appointment. Candor compels the admission that 
very many objects which seen under the micro- 
scope are very beautiful, cannot be successfully 
photographed. This is true of a majority of the 
histological and pathological preparations not 
mounted especially for this purpose. It is true as 
regards opaque objects, and objects of a deep red, 
yellow, orange, or brown color, as these are prac- 
tically opaque for the actinic rays. In short, 
success in photo-micrography depends to a con- 
siderable extent upon the selection of suitable 
objects, and upon mounting these in the best 
manner for the purpose in view. Some hints and 
directions will be given in regard to this important 
matter in the portion of this volume devoted to 
technology. 
The critics should remember in judging of the 
merits of a photo-micrograph, that it should not 
be compared with hand-work, which, intentionally 
or otherwise, is usually more or less diagrammatic 
or “conventionalized.” On the other hand, it 
should be compared with the picture seen under 
the microscope. Those who are not familiar with 
the views from nature obtained in this way, and 
who are familiar with the woodcuts commonly 
employed for the illustration of works relating to 
