270 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE. 



of rats which were in the early stages of the infection, having about twenty- 

 five organisms per field (4 mm. objective). Trypanosomal blood from 

 guinea-pigs is not suitable for isolation work. A white rat showing the de- 

 sired number of organisms in its blood was etherized, after which its blood 

 was drawn from the heart by means of a sterile special Novy heart pip- 

 ette^ (fig. VI). A droplet of this defibrinated nagana blood was smeared 

 over the surface of the medium by means of a capillarj- pipette and incubated 

 at the usual temperature of 25° C. after the tubes had been rubber capped 

 to prevent dessication. 



Cultural forms were observed as early as the fourth to the sixth day. It 

 is advisable, however, not to disturb the tubes until after a period of 14 days 



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7^c> 



Figure VI Tlu' Novy licait pipette used for bleeding rats. Fidl Size. 



has elai)sed when all the cultural tubes may be examined and transplants 

 made. Transfers should be made by means of the capillary pipette instead 

 of with a platinum loop and to perpetuate the cultural type transplants 

 should be made weekly. This medium gave 100 per cent positive growth. 

 These cultural forms are practically devoid of large globules, altho small 

 ones were i)resent. and in that respect more nearly resemble the blood type 

 which is free from globules. They differ from the latter type in that the cen- 

 trosome is near and usually situated anterior to the nucleus. Also the un- 

 dulating membrane is not nearly so conspicuous as in the blood form. 



Intraperitoneal and subcutaneous injections of these cultural forms after 

 several successive growths (generation seven) in vitro will infect rats and 

 guinea-pigs and the organisms which develop in the blood of the animal 

 after an injection of the cultural form are identical with those of the blood 

 type. 



SUM.MARY 



One part of a veal nutrient agar, plus two parts of defibrinated rabbit 

 blood devoid the white blood cell layer yields constant results and seems to 

 indicate that the conditions are more nearly ideal for the cultivation of 

 trjpanosoma Brucei in rilrn. 



6. .lour. Infect. Dis. V^ol. 20. 1917, p. rtO'Z. 



