MALARIAL PARASITES 17 1 



DIFFERENTIAL CHARACTERS OF THE HUMAN MALARIAL PARASITES. 



Essentially the method of cultivation, as used by Thomson, 

 is as follows : 10 c.c. of infected blood are drawn from a vein and 

 transferred to a sterile test tube, in which is a thick wire leading to 

 the bottom of the tube. One-tenth of a cubic centimetre of a 

 50 per cent, aqueous solution of glucose or dextrose is placed 

 in the test tube, preferably before adding the blood. The blood 

 is defibrinated by stirring gently with the wire. When defibrination 

 is complete the wire and the clot are removed, and the glucose-blood 

 is transferred, in portions, to several smaller sterile tubes, each con- 

 taining a column of blood about one inch in height. The tubes 

 are plugged and capped and then transferred, standing upright, to an 



