54 Sir D. Bruce and others. Trypanosomes of 



Six goats were also infected from goats; of these, three died and three 

 recovered. This variation in virulence may also be expressed, for the sake 

 of clearness, in the following table : — 



Table II. — Mortality among Goats infected in Various Ways by T. simice. 





Mode of Infection. 



Wild 

 Q-. morsitans 

 feeding. 



Wartliog blood, 

 injection of. 



Monkey blood, 

 injection of. 



Goat blood, 

 injection of. 



Percentage of deaths 



No. of goats employed 



86 -7 

 15 



o-o 



3 



16-7 

 6 



50 -0 

 6 



What does this table show ? It is meant to show that if goats are infected 



O 



with T. simice directly by the bite of the " fly," most of them will die, whereas 

 if the parasite is passed for a generation or two through goats, monkeys, or 

 the warthog, the rate of mortality for the goat will fall. But it may be 

 objected that the six goats which were infected with goat's blood have a 

 mortality of 50 per cent., which is almost as large as the wild G. morsitans 

 feeding experiments. But if Table I be referred to, it will be found that the 

 three fatal cases were inoculated with blood from a goat which had only 

 recently — some 10 days — been infected by the bite of the " fly," and ought, 

 on account of the shortness of the time, to be included in the first, or " fly "- 

 feeding, column ; the other three, non-fatal cases, from goats infected by the 

 injection of warthog's blood, should be included in the second column. If 

 this were done, then the table would appear as follows : — 



Table III. 





Mode of infection. 





Wild G. morsitans 



Warthog blood, 



Monkey blood, 





feeding. 



injection of. 



injection of. 



Percentage of deaths 



90 -0 



o-o 



16-7 



No. of goats employed 



18 



6 



G 



It must be confessed, however, that the numbers are small and subject to 

 a large margin of error, but the figures seem sufficiently remarkable to 

 merit record. It may also be remarked that the matter is of little practical 



