IV. THE MICROSCOPE. 



THE essentials of a microscope for bacteriological 

 work may be briefly summed up as follows : 



The instrument, of the monocular type, must be of 



FIG. 40. Microscope stand. 



good workmanship and well finished, rigid, firm, and 

 free from vibration, not only when upright, but also 

 when inclined to an angle or in the horizontal position. 

 The vari9us joints and movements must work smoothly 

 and precisely, equally free from the defects of "loss 

 of time" and "slipping." All screws, etc., should con- 

 4 49 



