THE MICROSCOPE AND MICROSCOPIC METHODS 2Q 



croscopical principle will at once suggest the importance of differ- 

 ential staining methods in microscopy. 



The Bacteriological Microscope. The bacteriological micro^ 

 scope consists of a tubular body which carries the optical parts, and 



FIG. 1 8. Microscope. 



which can be raised or lowered for focusing. The objectives should 

 be three in number, and should be attached to the body by means 

 of a triple nose-piece, which permits any objective to be turned into 

 the optical axis at will. The eye-piece slips into the upper and 

 opposite end of the body or tube. The arrangements for focus- 



