268 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE. 



in number. The groups are not usually arranged symmetrically like in the 

 rosettes of Trypanosoma Lewisi, but the effect is that of a Avrithing mass 

 with the flagella directed outward, being very suggestive of the snakes on a 

 Medusa head. However, at times symmetrical arrangement results and be- 

 cause of the presence of one or more highly refractive globules and the di- 

 rection of the flagella presents the picture of a jeweler's '"sunburst." There- 

 fore, Trypanosoma Lewisi and Brueei are easily and readily distinguished 

 from each other in-vitro. Again, since the former onlj^ infects rats and the 

 latter causes nagana in all the laboratory animals they may be easily separ- 

 ated w^hen occurring simultaneously in cultures or in the blood of a rat. 



The presence of the highly refractive globules in the cultures in-vitro 

 pre\aously referred to and their entire absence in the blood type seems to 

 indicate an unfavorable medium. It is then probable that with an improved 

 medium cultures may be obtained which would more nearly resemble the 

 blood type. 



Figure IV — The Novy carodit artery pipette used in bleeding ral>bits. One-half Size. 



The best results obtained in this direction were by employing a 1 to 8 

 nutrient veal extract agar. This was made as follows: 125 gms of chopped 

 veal and 1000 cc. of distilled water were thoroughly mixed and allowed to 

 digest over night in the ice-box. The mixture was then strained thru mus- 

 lin, 2 per cent peptone; 0.5 per cent sodium chloride; 0.5 per cent normal 

 sodium carbonate; and 2 per cent agar was added. This nutrient veal agar 

 was then boiled and filtered thru cotton, one cc. placed in each tube and 

 sterilized in an autoclave by heating to 105°C. for twenty minutes. 



The blood used in this cultural medium was drawn from the carotid 

 artery of a rabbit under aseptic conditions by means of a special Novy 

 pipette (fig. IV) and immediately defibrinated. It was then drawn up into 

 a Pasteur bulb pipette and transferred to sterile large special centrifuge 

 tubes (fig V) and centrifugated for 5 minutes at 8000 revolutions per minute. 

 This divides the blood into three lavers .serum, white, and red blood cell layers. 



