312 proceedings of the indiana academy of science. 

 The Cultivation of Tkypanosomes in Vivo. 



H. C. Travelbee. 



Practically all of the common laboratory animals are susceptible to try- 

 panosomal infection. For the following reasons white rats and guinea pigs 

 are the ones most frequently used; (a) they require but little space, (b) they 

 are easil\' kept, and (c) in them the infection runs an acute or sub-chronic 

 course. It is essential to know at all times the status of the infection and 

 the condition of the animal, and there are certain routine procedures which 

 are followed in making the observations on the culture. These routine pro- 

 cedures as carried out in the laboratories at Purdue University will be 

 described more or less in detail. 



The infection is transferred from animal to animal by the hypodermatic 

 injection of infected blood. The injections may be made subcutaneoush' 

 or intraperitoneally. The former method is usually used when it is desired 

 to have the course of the infection proceed slowly; and only small quantities 

 of blood are injected for that reason. The intraperitoneal method is used 

 when it is desired that the climax of the infection come quickly. In this 

 ease larger quantities of the virulent blood are injected. 



To transfer the infected blood a small hypodermatic needle is used, which 

 has been boiled for ten minutes in a saturated solution of borax, and then 

 rinsed thoroly with a sterile physiological salt solution. About 0.5 ec. of the 

 sterile salt solution is then drawn up into the syringe. A drop of the virulent 

 blood is then drawn up and mi.xed with the salt solution in the barrel of the 

 springe, and all or any fraction of it is injected into the animal, as it has been 

 shown that a single trypanosome when injected will cause a typical infection. 



Method.'^ of Obt.\ining tfie Virulent Blood. 



Rats are bled from the tip of the tail and Guinea pigs from the ear. The 

 rats are kept in large battery jars which have weighted Avire covers. Tl^e 

 cover is held slightly to one side and the rat's tail is drawn thru the opening 

 thus made until the rump is snugly against the edge of the jar and the rim 

 of the cover. The tail is taken in the left hand, the left forearm holding the 

 cover in place, and with a sharp pair of sterile scissors a bit is cut cleanly 

 from the end of the tail. It is important that this cut be made cleanly, for 

 if the tail is lacerated or if any shreds of tissue remain, the blood will run 

 back among the stubby hairs which cover the tail and will not form a drop 

 on the end of it. This drop which collects is drawn into the syringe, mixed 

 with the salt solution and injected. In the case of the guinea pig the ear is 

 held between the thimib and forefinger of the left hand. A clean cut is made 

 in the edge of the ear and the drop of blood which forms is taken into the 

 syringe in the same manner as the drop from the rat's tail. 



