46 



not protect against the other, hence the conclusion of the duahty of the 

 two trypanosomes. 



Conclusion. 



(1) Recovery of a goat from Trypanosoma sudanense gave immunity 

 against this strain. 



(2) The hlood of the immune animal was sterile. 



(3) The immunity did not protect against mbori strain, nor did mbori 



immunity protect against Sudanense strain. 



Morphologically identical with the Trypanosoma bnicei of Zululand 

 were also found to be two strains of trypanosomes found in Togo. Their 

 identity or otherwise formed the subject of investigations by Lavern 

 and Mesnil.* 



They experimented with a Nagana from Togo obtained from Prof. 

 Schilling, which they injected into a goat (this goat had recovered from 

 an infection due to the Zululand strain and its blood proved to be sterile) 

 together with a control ; thev both contracted the disease and died 

 respectively on the 34th and 35th days. Here the immunity of the 

 Zululand Nagana did not protect against Schilling's Togo strain ; hence 

 the conclusion that this latter one is not Nagana. 



Conclusion. 



(1) Immunity of Trypanosoma hrucei of Nagana strain of Zululand 



did not protect against Schilling's Nagana strain of Togo. 



(2) The blood of the goat which had recovered from a Nagana infection 



proved to be sterile. 



Observations recorded by Kochf concerning a Togo strain of 

 Trypanosoma brucei are of utmost interest to us. 



Two horses, a mare and a stallion, were imported from the Hinterland 

 of Togo to Berlin. En route they had to pass a tsetse belt. They con- 

 tracted a trypanosomiasis (called the Togo-Martini strain of Nagana). 

 The stallion died about four months after infection, and its blood proved 

 to be highly virulent for any experimental animals which were injected. 

 The mare remained in good condition ; microscopical examination did 

 not reveal the presence of trypanosomes, which were only demonstrated 

 after large doses of blood had been injected into dogs. Contrary to the 

 experience with the stalhon, the mare's trypanosomes were but slightly 

 virulent for smaller animals and these recovered to a great extent. Finally 

 the mare, which remained over a year in perfect health, was inoculated 

 with the trypanosome originating from the stallion, and now she developed 

 an acute tsetse disease from which she died. Koch interpretes this to a 

 different virulency of the two strains, although the horses had become 

 infected in all likelihood at the same time and at the same place. 



* Comptes Rendus, 25/6/06. 

 t Deutsche Med., Woch., 1901, 



