PROTOZOA 207 



blood of infected animals contains the organism, and can, if 

 injected, produce the disease without the agency of the fly. 

 So far the tsetse-fly alone is responsible for the spread of the 

 infection. 



Sleeping Sickness. Trypanosoma Ugandense Gam- 

 biense (Button, 1904). (T. Castellani, T. Hominis, T. 

 Neprevi.) Sleeping sickness, or human trypanosomiasis, is a 

 disease peculiar to some parts of Africa. It is accompanied 

 by periods of fever, anemia, and, finally, a lethargy deepening 



Fig. 105. Trypanosome from blood of gray rat; stained with a 2 per 

 cent, aqueous solution of methylene-blue (Boston). 



into coma and death. The disease may be rapid, and it 

 may last with recurrences for many years. Trypanosomes 

 identical with those found in nagana disease have been 

 found in the blood of infected persons, and described by 

 various observers, and given different names. 



Monkeys, when inoculated with cerebrospinal fluid from 

 affected persons, develop a similar disease, and the parasites 

 are found in the blood. So far the organism has not been 

 cultivated. 



