HISTORY -jpg 



Disappearance after death. Trypanosoma disappear very 

 suddenly after the death of the host. Within two hours signs 

 of degeneration begin ; the parasites shrink, assume irregular 

 shapes and then disappear. Motile forms are rarely found 

 after two hours. 



Distribution in nature. Trypanosoma are not known to 

 exist in nature outside of the bodies of living animals. They 

 have been found in the blood of a large number of species. 

 Novy has found them in the blood of many birds. They 

 have been kept alive in blood or salt solution for a few hours. 

 Novy has succeeded in cultivating them, i. e., getting them to 

 multiply on an artificial culture medium. 



§ 307. Historical sketch. There is a voluminous 

 literature on the trypanosoma from which the following brief 

 summary was taken. In 1841, Valentin discovered hematozoa 

 in trout {Salmo fario) and in 1842, Glugge found them in the 

 blood of frogs. In 1843, Gruby observed a flagellate infusorium 

 in frogs which he named Tr. sangimiis. Gruby has generally 

 been credited with the discovery of these forms. From 1843 

 to 1879 the organisms were found by many observers, not only 

 in frogs but in birds as well. 



In 1879-80, Lewis described trypanosoma found in rats in 

 India. Later he states that they are identical with Tr. Evansi. 



In 1880, G. Evans discovered trypanosoma in the blood 

 of horses suffering with surra, the well known disease of 

 India. He proved their causal relation to the affection. In 

 1885, Steele confirmed Evans' work, and named the parasite 

 Spirocheta Evansi. 



The work of Evans and Steele was followed by many 

 interesting discoveries of trypanosoma especially in fish and in 

 man. 



In 1896, Rouget described Trypanosoma found in the 

 blood of a horse suffering from dourine. Wasilewsky and 

 Senn, in 1899, confirmed Rouget's work and determined the 

 pathogenic action of this parasite for the horse. Laveran and 

 Mesnil proposed the name Tr. rougeti for the parasite of 



Digitized by Microsoft® 



