212 Piroplasma canis 
18. v. 07. Result negative. No parasites found. The fox was killed and all the 
organs were carefully examined. Ten c.c. of the fox’s heart-blood were 
injected into a dog, but the dog remained well. 
Controls: Two dogs were inoculated with 4 c.c. each of the same samples of blood 
which were injected into the fox (26. xv. and 1. iv. 07). Both con¬ 
tracted fatal piroplasmosis. 
Experiment II .—-Young Fox. 
15. v. 07. Received 3 c.c. of blood from the heart of a dog dead of piroplasmosis. 
20. v. 07. Fox found dead ; autopsy negative. 
Control: A dog inoculated with 3 c.c. of the same blood which was injected into the 
fox, was killed on 20. v. 07 when moribund from piroplasmosis. 
Experiments III, IV, V. Three young Foxes. 
28. vn. 07. The foxes each received 4'5 c.c. of virulent blood. 
The foxes remained well for over a month. 
A dog which received an inoculation with the blood of Fox III on 27. vni. 
remained free from piroplasmosis, but died from other causes a month 
later. 
Control: A dog, inoculated with 2 c.c. of the same blood which was injected into the 
foxes, was killed on 1. vm. when moribund from piroplasmosis. 
Result: The four experiments prove that the fox is immune to 
South African piroplasmosis. 
Experiments on the Jackal, Canis mesomelas Schreb. 
Lounsbury, in his report as Entomologist to the Department of 
Agriculture, Cape of Good Hope (1903, p. 42), briefly states that he 
failed to infect a jackal either by inoculation or the application of ticks. 
Mr Lounsbury has kindly sent us the complete record of this experi¬ 
ment, together with the record of a second (unpublished) experiment, 
which was also negative, carried out in May, 1908. 
The following is a summary of these experiments: 
Experiment I .—Lasting from 30 Jan. to 20 Mar. 1903. 
(30. i. 03.) 
1. The jackal was infested heavily with pathogenic Haemaphysalis leachi. 
(Specimens of the same lot of ticks produced many cases of piro¬ 
plasmosis in dogs without failures.) 
6. Many ticks attached. Animal scratches at them a great deal. 
8. 3 partly gorged female ticks scratched or taken off. 
9. 12 gorged female ticks removed; 1 found loose in box. 
10. about 20 ,, ,, ,, 
11. about 6 ,, ,, ,, 
(Judging from the number of female ticks which were recovered, at 
least 80 males and females must have become attached to the 
jackal.) 
