Cattle as a Reservoir of the Virus of Sleeping Sickness. 481 



I. Arc Cattle capable of being Infected with Sleeping Sickness by the Sub- 

 cutaneous Injection of Blood containing Trypanosoma gambiense ? 



Experiment 869. Bull. 



September 10, 1909. — A bull was inoculated with 5 c.c. of blood containing large 

 numbers of Trypanosoma gamhieiisc from an infected monkey. 



Its blood was examined daily, and 18 days after injection the bull was found to be 

 infected with Trypanosoma gamhiense. The identity of the trypanosome was established 

 by injecting a monkey with some blood from the ox. This monkey showed T rypanosoma 

 gamhiense on the sixth day. 



Conchision. — From this experiment it is seen that oxen are capable of being infected 

 with Sleeping Sickness by the injection of blood containing Trypanosoma gambiense. The 

 trypanosome appears in small numbers in the blood, and the blood, when injected inta 

 susceptible animals such as monkeys, gives rise to a fatal form of the disease. 



II. Can Cattle be Infected with Sleeping Sickness hg the Bites of 

 Artificially -infected Glo^ina palpalis ? 



The two following experiments were carried out by feeding Glossim 

 palpalis first on an infected monkey and immediately afterwards on a 

 healthy ox. Wild flies from the Lake-shore were used. 



Experiment 890. Ox. 



May 20, 1909. — The ox was thrown and a monkey heavily infected with Sleeping 

 Sickness was laid aci'oss its flank. Two cages of Glossina palpalis, containing 100 and 

 150 flies respectively, were allowed to feed for a few seconds on the monkey and then on 

 the ox. The flies were allowed from 30 to 35 interrupted feeds on each animal every day. 

 This was continued for 38 days, during which time 561 flies were estimated to have fed 

 on one or other animal. 



July 17. — Fifty-eight days after the first infected feed, Trypiunosoraa gamhiense appeared 

 in the blood of the ox. 



The identity of the trypanosome was established by injection of the ox's blood into two 

 monkeys. The first monkey was injected with blood from the ox 7G days and the second 

 monkey 181 days after the flies had first fed on the ox. Both monkeys developed 

 Sleeping Sickness, the first 7 days and the second 11 days after injection of the blood. 



Experiment 891. Calf. 



The details of this experi&ent were similar to those of the last. Trypanosoma, 

 gamhiense appeared in the blood of the calf 57 days after the flies had been first fed 

 upon it. 



Three cubic centimetres of the blood of the calf were injected into a monkey, and the 

 monkey developed Sleeping Sickness after an incubation period of 8 days. 



Conclusion. — These two experiments show that when artificially infected Glossina 

 palpalis are allowed to feed on healthy cattle, these animals develop Sleeping Sickness, 

 and that the blood of the cattle is capable of giving rise to infection of Trypanosoma, 

 gambiense in monkeys when injected into them. 



