THE NON-PATHOGENIC MAMMALIAN TRYPANOSOME 405 



rabbit's blood in equal parts, when forms from 1 1 to 60 ^ in length may be 

 found, and also rosettes, but the forms are herpetomoniform, with the kine- 

 to nucleus at the flagellar end. 



Pathogenicity. — Inoculation can only be carried out successfully in rats, in 

 which it is generally non-pathogenic, though some observers have described 

 the rare occurrence of dyspnoea, oedema, and subcutaneous haemorrhages in 

 intense infections. Some strains may become very pathogenic for rats. 

 These strains show morphological and developmental anomalies — e.g., forms 

 without a blepharoplast — and there is a correlation between virulence and 

 these changes. 



Immunity. — Immunity is gained when a rat becomes free from the parasites, 

 and hyperimmunity can be obtained by inoculations. It is thought that the 

 immunity is largely due to phagocytosis, but this is being questioned in many 

 species of trypanosomes. A protective serum is obtainable from hyperimmune 

 rats. Immune serum will agglomerate the trypanosomes. 



Hereditary Infection. — -The parasites cannot be transmitted from the mother 

 to young, as it appears that they cannot traverse the placenta. 



Genus Endotrypanum Mesnil and Brimont, 1908. 



Definition. — Trypocastellanelleae, found in mammals, non-pathogenic, and 

 with endoglobular forms. 



Type Species. — Endotrypanum schaudinni Mesnil and Brimont, 1908. 



Endotrypanum schaudinni Mesnil and Brimont, 1908. 



This trypanosome, 1 3*4 X 3'5 microns, is only known in the endoglobular form 

 in the red blood cells of the sloth, in which it appears as a peg-top-shaped try- 

 panosome with a short fiagellum possessing trophonucleus and kinetonucleus. 

 This must be only one stage in its life-history, and as yet the other stages are 

 unknown; and though a free trypanosome was seen in the same animal as the 

 encysted forms, it was considered to be different from the endoglobular forms. 

 In 1914 Darling confirmed these researches, finding the organism in Cholospus 

 didactylus in Panama. No free trypanosomes were seen in the sloth. Free 

 forms only occur after fresh preparations have stood some time. 



Unclassifiable. 



The following is a list of the unclassified species, divided 

 according to the classification of the host and arranged according 

 to known importance : — 



Trypanosomes found in Monkeys. — America : T . minasense Chagas, 

 1909; T. prowazeki Gossler, 1908. Asia: T. rhesii Terry, 1911; 

 T. vickerscB Brumpt, 1900, Africa : A nmnber of unnamed trypano- 

 somes are reported in chimpanzees and species of Cercopithecus, . 



Trypanosomes of Ungulata. — Trypanosoma theileri Bruce, 1902. 



Trypanosomes of Rodents. — T. duttoni Thiroux, 1905; T. musculi 

 Kendall, 1906; T. grosi Laveran and Pettit, 1909; T. microti 

 Laveran and Pettit, 1909; T. hlanchardi Brumpt, 1905 ( = r. myoxi 

 Blanchard); T. evotomys Hadwen; 7". peromysci Watson; T. criceti 

 Liihe, 1906; T. cuniculi R, Blanchard, 1906; T. bandicottiLingaiTd, 

 1904; T. nabiasi Railliet; T. leporis sylvatici Watson; T. acouchii 

 Brimont; T. indicum Liihe; T. ciielli Watson; T. spermophili 

 Laveran; T. otospermophili Wellman and Wherry; T. petrodromi 

 Bruce, 1915. 



Trypanosomes of Bats. — T. vespertilionis Battaglia, 1904; T. mega- 

 dernta Wenyon, 1908: T. nicolleorum Ed. and Et. Sergent, 1905; 

 T. limeatus Iturbe and Gonzalez, 1916. 



