24 



GENERA L MO HP HO LOG Y 



or when stained by appropriate dyes, especially those 

 derived from coal tar, methylene blue and fuchsin. 



FIG. 1. Microscope: A, ocular or eye-piece; B, objective; 

 C, stage; D, "iris" diaphragm; E, reflector; F, coarse adjustment; 

 G, line adjustment; H, substage condensing apparatus; /, nose-piece. 



Bacteria are exceedingly small single cells, in their 

 natural state transparent, colorless, and apparently 



