causing Disease in Man in Nyasaland. 221 



Experiment 4, Monkey 2164, Naturally Infected Dog Strain. 



Date. 



Expt. 



Source of virus. 



Strain of 

 trypanosome. 



Period of 

 incubation, 

 in days. 



Duration of 

 disease, in 

 days, or 

 recovery. 



1913. 













May 14 ... 



2164 



From Eat 2091 



Naturally infected 











Dog 2033 







June 14 ... 



2164 



From Dog 2157 



Naturally infected 











Dog 2033 







July 31 ... 



2164 



From Eat 2285 



Naturally infected 











Dog 48 







Dec. 17 ... 



2164 



From Eat 2437 



Human 



7 



Alive 1.3.14 1 









Remarks. — Monkey 2164, which was proved to be immune against the Naturally Infected 

 Dog Strains 2033 and 48, reacts readily to the Human strain. 



Conclusion. — Immunity to the Naturally Infected Dog strain does not imply immunity to the 

 Human strain, Dongolosi. 



Experiment 5, Dog 690, Naturally Infected Dog Strain. 



Date. 



Expt. 



Source of virus. 



Strain of 

 trypanosome. 



Period of 

 incubation, 

 in days. 



Duration of 

 disease, in 

 days, or 

 recovery. 



1912. 













July 17 ... 



690 



Naturally infected 



Naturally infected 



? 



E. 







Dog 690 







Nov. 22 ... 



690 



From Eat 1492 



Naturally infected 













Dog 48 







Dec. 20 ... 



690 



From Dog 1675 



Wild G. morsitans 



10 



43 



Remarks.- — Dog 690, which had recovered from Naturally Infected Dog Strain 690, and proved 

 immune to Naturally Infected Dog Strain 48, succumbs in 43 days to the Wild G. morsitans strain. 



Conclusion. — The Naturally Infected Dog strain does not protect against the Wild G. morsitans 

 strain. 



Experiment 6, Dog 1530, Naturally Infected Dog Strain. 



Date. 



Expt. 



Source of virus. 



Strain of 

 trypanosome. 



Period of 

 incubation, 

 in days. 



Duration of 

 disease, in 

 days, or 

 recovery. 



1912. 













Oct. 29... 



1530 



From Eat 1491 



Naturally infected 



16 



E. 









Dog 48 







1913. 













March 21... 



1530 



From Eat 1991 



Naturally infected 













Dog 48 







April 11... 



1530 



From Guinea-pig 2034 



Wild G. morsitans 



10 



23 



Remarks. — Dog 1530, after having recovered from Naturally Infected Dog Strain 48, and shown 

 to be immune on reinjection, readily succumbs to one injection of the Wild G. morsitans strain. 



Conclusion. — The Naturally Infected Dog strain does not protect against the Wild G. morsitans 

 strain. 



VOL. LXXXVIII. — B. S 



