SECRETIONS AND EXCRETIONS. 



239 



in the diagram, and as soon as the blood-drop has 

 spread along the line of contact, draw the upper slide 

 gently along the surface of the lower, thus spreading 

 the blood in a thin film. Dry this by waving in the air. 

 Do not heat. Repeat the process, using the edge of 

 the prepared slide to spread the blood upon the other 

 slide. The blood should be taken before quinine has 

 been administered, as quinine quickly expels most of the 

 malarial parasites of this latitude from the capillary 

 blood. Under such circumstances negative reports 



Fig. 30. 



count for little or nothing. The blood should be drawn 

 just hejore, during^ or just after the supposed malarial 

 paroxysm, as the parasite is present in the capillaries 

 in much greater numbers at those times." 



When cover-glasses are preferred, two or more cover- 

 glasses are cleansed in precisely the same way as 

 described for slides. A small drop of blood is caught in 

 the center of one cover-glass by bringing the latter in 

 contact with the former. Then the second cover-glass 

 is allowed to fall gently upon the other. If the glasses 

 have been well cleansed, the blood will immediately 



