CHAPTER XVII. 
MICROSCOPICAL TECHNIQUE. COVER- 
GLASS PREPARATIONS. SECTION - 
CUTTING AND STAINING. 
F OR the production of perfect photo-micrographs, 
two things are required—good preparations and 
good photography. We have tried in the foregoing 
chapters to make clear the way to good photography, 
but as an imperfect preparation will never yield a 
perfect photograph we propose to devote this chapter to 
an outline—it can be no more—of the methods we have 
found the best for the production of good preparations. 
These suggestions must be more or less confined to 
medical microscopical technique, simply because the 
writer has no trustworthy knowledge or experience of 
any other. The preparation of insects, diatoms, botani¬ 
cal specimens, etc., is no less important, but while 
the general principles involved are the same as for 
medical work, we elect to give no suggestions on these 
subjects rather than perfunctory ones which might 
be misleading. 
Whatever system of staining we employ, the stain 
must be discrete and selective . So far as possible, each 
