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Trypanosomiasis in monkeys (Macacus rhesus) in captivity. 

 By B. T. TERRY. 



[From the Laboratories of the Rockefeller Institute for Medical 

 Research, New York City.] 



In the blood of an experimental monkey (Macacus rhesus), 

 Dr. Richard Lamar found on October 28, 191 1, an actively motile 

 trypanosome. This discovery led to my examining the blood of 

 all of the monkeys at the Rockefeller Institute. 



In examining 130 monkeys, 28 were found infected with 

 trypanosomes. The infected monkeys had been used for experi- 

 ments between July 17 and October 6. Six monkeys used on or 

 before July 17 were negative, and 80 others, some normal, the 

 rest used after October 6, were also negative. 



With but one exception, all of the monkeys examined belonged 

 to the Macacus rhesus species. 



The trypanosomes found in the 28 monkeys were apparently 

 of the same kind. They have been successfully inoculated into 

 one monkey (Macacus rhesus), six mice, two rats, one guinea pig, 

 and one young rabbit. In none of these animals has a rich infec- 

 tion been seen. The two rats were infected on the 8th day, the 

 six mice between the 9th and the 52d day, the guinea pig and 

 rabbit on the 16th day, and the monkey between the 16th and the 

 24th day. The trypanosomes do not appear to be very patho- 

 genic. 



The micronucleus is usually at the extreme posterior end of 

 the parasite, is strikingly large, measures \\i or more in diameter, 

 and often projects on either side of the parasite. The nucleus is 

 oval, measures 1% to 2%m in its long diameter, and is situated 

 near the juncture of the anterior ^5 and the posterior of the 

 body. The flagellum is very long, the free part measuring 10 to 

 i2j^M- The entire length of the parasites thus far measured has 

 varied between 25 and 28//, the breadth between 2 and 2 x /\y.. 



If the future shows that the trypanosomes here described 



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