196 Methods of Observing Micro-organisms 



i. Cover-glasses. The glasses should be perfectly clean and freed 

 from fat, either by washing in alcohol and ether and wiping with 

 a clean soft cotton cloth or Chinese rice paper, or by flaming. 

 The drop of blood should be small and should be placed 

 upon the center of one glass and immediately covered by 

 another, so held that the corners do not coincide. As soon 

 as the drop is fairly well distributed the glasses are gently 

 slid apart. 



Fig. 



36. Method of making dry film with two cover-glasses (from 

 Daniels' " Laboratory Studies in Tropical Medicine"). 



Slides. The slides, like the cover-glasses, must be perfectly 

 clean. The drop of blood is placed upon one slide at about 

 one-fourth the length of the slide from its end, touched with 

 the end (it must have ground edges) of the second slide, and 

 then gently pushed along until the fluid is exhausted. 



Fig. 37- Method of making dry films with two slides (from Daniels' 

 " Laboratory Studies in Tropical Medicine "). 



