510 The Philippine Journal of Science mz 



Elsewhere they state, in discussing a trypanosome disease of 

 horses in Annam, that Vassal (3) found that — 



The blood of leeches which had fed on infected animals was infective, 

 on injection into rats, immediately after the meal of blood, but not four 

 hours later. The trypanosomes are killed off very readily in the stomach 

 of the leech. 



Daniels and Alcock state (4) : 



Many parasites maintain their virulence for a considerable period in the 

 stomach of leeches, but leeches are not known to act as carriers of disease. 



Nencki, Sieber, and Wijnikewitch (5) allowed leeches to feed 

 upon animals infected with rinderpest. Later they ■examined 

 the blood in these leeches for the presence of the organism re- 

 garded by them as the causative agent of rinderpest, but without 

 success. 



The leech employed in these experiments is a new species, 

 Hirudo hoyntoni.^ 



The leeches used in the first of the following experiments 

 were procured from La Carlota, Occidental Negros, a locality 

 which for several years has not been known to be infected with 

 rinderpest. It was thought best to select leeches from such an 

 uninfected region when beginning the study. 



On July 13, 1912, ten leeches were allowed to feed on bull 

 3397, in the second day of febrile temperature of an attack of 

 rinderpest. As soon as the leeches had become engorged, they 

 were placed in water and kept in a cool place. The virulence 

 of the blood in these leeches was tested upon cattle after various 

 intervals, as described in experiments 1 and 2. 



Experiment 1. — At 10.00 a. m., July 14, twenty-four hours 

 after the leeches had fed on the sick animal, 2 leeches were 

 placed in 50 cubic centimeters of physiological salt solution, 

 which caused them to disgorge the blood. The mixture of dis- 

 gorged blood and salt solution was injected subcutaneously into 

 bull 3396, which was placed in a screened stall. This animal 

 did not contract the disease, but at a later date proved to be 

 susceptible. 



Experiment 2. — On July 15, two of the leeches which had fed 

 on July 13, were placed in 50 cubic centimeters of physiological 

 salt solution which caused them to disgorge the blood which 

 they had held for forty-eight hours. This mixture of blood and 

 salt solution was injected subcutaneously into bull 3390. The 



Wharton, L. D., This Journal, Sec. D (1913), 8, 369. 



