56 THE ANIMAL PARASITES OF MAN 



consider that this case either is convincing. As a matter of course 

 the appearance of cercomonades in the urine of man cannot be dis- 

 puted, but hitherto no proof has been adduced to show that they 

 live in man. 



4. Trypanosoma, Gruby, 1843. 



Since the 'forties we have- known through Valentin, Gluge, 

 Remak, &c., of flagellates in the blood of fishes and amphibia, and 

 soon afterwards these parasites were found in the blood of rats 

 and marmots. The species living in European frogs was called 

 Trypanosoma sanguinis by Gruby. 1 



At the present date we distinguish a larger number of species 

 which live, some of them, in the blood of various vertebrates, 

 and some of them in the intestine of vertebrate and invertebrate 

 animals. A few forms have acquired great importance from the 



(a) '(b) 



FIG. 17. Trypanosoma Lewisi, Kent. 

 From the blood of a rat ; O'OoS-o'Oio mm. 

 in length ; (a) fresh ; (b) preserved ; the 

 nucleus is at the flagellated end. (After 

 Kempner and Rabinowitch.) 



fact that they cause more or less serious diseases in domestic 

 animals, and that their presence not only endangers the lives of 

 the latter, but frequently decimates them. Thus Trypanosoma 

 brucei, Plimm and Bradf., is known to be the cause of the dreaded 

 Tsetse fly disease (nagana), occurring in various parts of Africa ; 

 T. evansi (Steel) induces the disease known as surra, which 

 occurs in Southern Asia ; while T. equiperdum, Dofl., plays a 

 part in dourine, a disease observed in N. Africa, the south of 

 France, and Spain. 



According to a report from Nepveu, 2 trypanosomes also occur 

 in the blood of man, but this seemed doubtful, as the observa- 

 tions were made in Algiers in patients suffering from malaria, and 

 it was not unreasonable to surmise that developmental stages of 



1 Gruby, " Sur une nouv. esp. d'hematoz." (C. R. Ac., Paris, 1843, xvii., p. 1134;' 

 Ann. sc. nat. zool., 1844, i-> P- 104). 



3 Nepveu, C. R., soc. bioL, Paris, 1898 (10), p. 1172. 



