236 Proceedings of Indiana Academy of Science 



the maximum 74 hours, while the minimum duration of the disease was 

 20 hours and the maximum about 140 hours. The average period of 

 incubation was about 23 hours and the average duration 80 hours. 



During the course of the disease these animals seem to be normal 

 except possibly during the last day when they may be more or less drowsy. 

 There are no morbid s>Tnptoms or lesions and both rats and mice 

 may or may not die with convulsions. They are, however, excitable and 

 if excessively annoyed convulsions usually occur just previous to death. 



Experiments with dogs. — Probably the dog is the most susceptible 

 animal, excepting the rat and mouse. If the duration of trypanosomiasis 

 is short, only a week or two, the development of the parasites is rapid 

 and regular. On the other hand, if the disease runs along for three or 

 more weeks there may be an increase in the number of trypanosomes 

 at first, followed by an abrupt decrease, but at no time does the parasite 

 entirely disappear from the blood stream. In this respect it is unlike 

 the subacute or chronic variety of the disease. There may be several 

 such relapses followed usually by a marked increase before death. 



In the four dogs used in the experiment (table II) the minimum 

 period of incubation was two to four days, the maximum 

 seven to nine days; the minimum duration of the disease 

 six days and the maximum duration 26 days. The average period 

 of incubation was 4.3 to 6.3 days while the average duration was 16.3 

 days. The animals seem to become extremely weak and there is a loss 

 in weight. There is marked hypertrophy of the inguinal glands, the 

 vision appears to be disturbed and there is a rise in temperature. 



luocnhition with Culti(res Grown in vitro. 



The medium employed to obtain this strain of Trijpanosoma bnicei 

 was a modification of the original Novy and MacNeal blood agar. The 

 isolation was obtained by using a pea and bean blood agar or a serum 

 agar as described by the author in 1916.' The parasite aftei- becoming 

 well established outside of the animal was perpetuated upon blood agar 

 medium. 



TABLE II. Inoculation of Dogs witli Cultures CJrown in vivo. 



* Proceedings of the Ind. Acad, of Sci. 1916. pp. 264-271. 



