518 I'he Philippine Journal of Science 1913 



blood. In the following experiments guinea pigs were used 

 since they are susceptible to surra. 



On April 21, 1913, four leeches were fed for fifteen minutes 

 on a guinea pig whose blood was heavily infected with the try- 

 panosomes of surra, after which the leeches were placed in 

 water and kept in a cool place. The infectivity of these leeches 

 with regard to surra was tested in experiments 31 and 32. 



Experiment 31. — On April 23, 1913, two days after the leeches 

 had fed, 2 of them were allowed to feed on 2 healthy guinea 

 pigs. These animals were kept under observation for one month, 

 during which time they were not found to be infected. 



Experiment 32. — On April 23, 1913, two days after the leeches 

 had fed, 1 leech was placed in a small amount of physiological 

 salt solution and thoroughly disintegrated in a mortar. The in- 

 gested bood was examined microscopically for trypanosomes, but 

 none were found. The remaining blood was injected into a 

 guinea pig, which was kept under observation for one month, but 

 did not develop the disease. 



Experiment 33. — On April 27, 1913, two leeches were allowed 

 to feed for seven minutes on a guinea pig heavily infected with 

 surra, after which time they were removed, kept out of water, 

 and placed on a healthy guinea pig. They commenced feeding 

 on the healthy guinea pig in seven and in seven and one-half 

 minutes, respectively, after having been taken from the infected 

 animal, and were allowed to feed upon the healthy animal for 

 ten minutes. This guinea pig was kept under observation one 

 month, but remained negative for surra. 



Experiment SJt. — On April 27, 1913, two leeches were allowed 

 to feed for ten minutes on a guinea pig heavily infected with 

 surra, after which they were placed on a healthy guinea pig. 

 They began feeding on the healthy animal in one hour and two 

 minutes and one hour and five minutes, respectively, after being 

 removed from the infected animal. This guinea pig was kept 

 under observation for one month, but remained negative for 

 surra. 



During the early part of May, 1913, I visited the Province 

 of Ilocos Sur to study some mild cases of rinderpest. On May 

 3, 1913, one leech was allowed to feed on a carabao which had 

 shown no symptoms of rinderpest except ulcers in the mouth. 

 The temperature of this animal had not been observed. It has 

 been my experience to find no ulcers forming in the mouth in the 

 virulent type of the disease until three or four days, and some- 

 times longer, after the initial rise in temperature. In a mild 

 type of rinderpest, undoubtedly, a longer period than this would 



