On Nagana, or Tsetse Fly Disease. 105 



of infected blood, never showed the slightest sign of the disease. 

 Rouget (op. cif.) also failed to infect animals by the mouth. 



Two rabbits, into whose conjunctival sacs several drops of blood 

 containing very abundant hsematozoa, and a third rabbit whose eye 

 was brought into contact with one of these, did not become infected. 

 We presume that Rouget's positive results by this method were due to 

 some accidental lesion. 



A dog suffering from the disease did not infect her puppies during 

 the last fourteen days of her life, nor did these puppies infect their 

 foster mother (she-cat) after they had been inoculated. 



Nor have we observed transmission of the disease through the 

 mother's milk in guinea-pigs. Rouget alludes to a doubtful instance of 

 infection by coitus in rabbits by means of the spermatic fluid. We 

 have not detected hsematozoa in spermatic fluid obtained from the 

 vesiculse seminales, and believe that in Rouget's single positive case 

 there may have been direct infection from the penis, which suffers con- 

 siderably in rabbits and may become excoriated, so that it easily 

 bleeds. 



We therefore do not believe that it is possible to infect an animal by 

 feeding in the absence of superficial lesions, and in this respect we 

 differ from Bruce, who seems to imply that the hsematozoa can pass 

 through the unbroken surface of the alimentary tract. 



IV. Symptoms and Course of the Disease. 



These vary somewhat according to the nature of the animal, but 

 there are certain striking symptoms which commonly occur in different 

 groups of animals. These may therefore be regarded as the most 

 characteristic. 



1. Muscular wasting and loss of power are evident in all but the small 

 animals. In rats, mice, and guinea-pigs they are but little marked or 

 absent altogether. In the horse, dog, cat, and rabbit the wasting is 

 very conspicuous. In the cat, dog, rabbit, and hedgehog there is 

 marked loss of weight, amounting to 20 30 per cent. 



2. Fever. In most animals which have been examined, there is a 

 smart rise of temperature about the time of appearance of hsematozoa 

 in the blood. (Horse, 41-5 C. ; dog, 40 C. ; rabbit, 41 C.; guinea- 

 pig, not constant.) 



Paroxysms of fever are common in the horse, as has already been 

 shown by Bruce. The temperature may rise to a considerable height 

 (41-6 C.); the same is true of the zebra-horse hybrids. In a horse 

 upon which daily observations were made, quick and sudden rises of 

 temperature immediately followed an increase of the hsematozoa in the 

 blood. At the time of death there was marked pyrexia. 



In the single donkey which we examined the temperature was gener- 

 ally raised throughout the course of the disease. 



