80 THE ANIMAL PARASITES OF MAN 



parasite usually found in man and in animals sub-inoculated from 

 cases of sleeping sickness in Nyasaland. It has since been found in 

 German East Africa and Portuguese East Africa, while Ellacombe 

 has described a case from North-western Rhodesia. 



(3) Serum Reactions. Interesting experiments on this subject were 

 performed during 1911 and 1912 by various French investigators. 



(a) Action of Immune Serum (Mesnil and Ringenbach) 1 : (i) A goat 

 was infected with T. rhodesiense. Twenty-two clays later its serum 

 mixed with T. rhodesiense was injected into a mouse. Result: Pro- 

 tection. (2) The serum mixed with T. gambiense was injected into 

 a mouse. Result : Infection. 



(b) Action of Baboon Serum. Contrary to T. gambiense, T. rhode- 

 siense is very susceptible to human and baboon sera. Mesnil and 

 Ringenbach 2 showed that a dose of i c.c. of baboon (Papio anubis) 

 serum cured mice infected with T. rhodesiense. In the same dose it 

 acted very feebly on T. gambiense. 



(c) Action of Human Serum. i c.c. of human serum cured T. 

 rhodesiense mice in three out of four cases ; on T. gambiense mice 

 there was no appreciable effect. 



Laveran and Nattan-Larrier 3 have shown the same, namely, that 

 human sera act on T. rhodesiense, but are quite without action on 

 T. gambiense. 



(d) Trypanolytic Reactions. Mesnil and Ringenbach 4 have also 

 shown that the sera of animals (man, monkey and guinea-pig) 

 infected with T. gambiense are trypanolytic for the homologous 

 trypanosome, that is, T. gambiense, but have no action on the hetero- 

 logous trypanosome, that is, T. rhodesiense. 



(4) Cross Immunity Experiments. (a) Mesnil and Ringenbach 5 

 immunized a monkey (Macacus rhesus) against T. gambiense. It was 

 inoculated with T. rhodesiense on June 7, 1911 ; on June 27 trypano- 

 somes appeared, the infection being slight ; on July 4 it died. A 

 control died in ten and a half days. 



(b) Laveran 6 immunized a goat and mice against T. gambiense. 

 When they had acquired a solid immunity, they were inoculated with 

 T. rhodesiense. They became infected like the controls. 



(c) Laveran and Nattan-Larrier 7 immunized a ram against T. brucei, 

 it subsequently became infected with T. rhodesiense. 



(d) Laveran 8 immunized a ram and a sheep against different strains 

 of T. brucei. Inoculated with T. rhodesiense they both acquired acute 

 infections and died. Conclusion : T. rhodesiense is not T. brucei. 



1 C.R. Soc.BioL, Ixxii, p. 58. 2 C.A\ Acad. Sti., 153, p. 1,097. 



3 C.R. Acad. Sci., 154, p. 18. 4 C.R. Soc. Biol., Ixxi, p. 609. 



5 C.R. Soc. Biol., Ixxi, p. 271. 6 Bull. Soc. Path. Exot., v, pp. 26, 241. 



7 C.R. Acad. Set., 154, p. 18. 8 Bull. Soc. Path. Exot., v, p. 101. 



