STATE HYGIENE 611 



allowing them to be bitten by a blood-sucking fly. The 

 disease cannot be produced by inoculating with the blood, 

 and is the sole exception in this respect to the group to 

 which it belongs. 



Gambian horse disease, due to a trypanosome, has recently 

 been discovered by Dutton and Todd in Gambia. It is 

 attended by anaemia and slight paresis. 



SOUTH AFEICAN ' HOESE SICKNESS.' 



This disease, to which no name has been given excepting 

 the above, is the scourge of equines in South Africa. 

 During certain years it causes immense losses, and invades 

 parts of the country which are usually free ; in other years 

 it is comparatively mild. There are certain places where 

 it is enzootic, and the disease may be looked for with great 

 regularity. Such places are low lying, and are frequently 

 associated with malarial attacks in man. 



Altitude is a great protection, so much so that it is a 

 common custom for farmers to send their horses away to 

 higher ground from unhealthy places before the season 

 begins. At the same time there are low-lying places in 

 Cape Colony, for instance, where the disease is seldom seen. 



The organism which produces this affection has never 

 been seen owing to its extreme minuteness, nor has it been 

 possible even with the closest grain of porcelain filter to 

 separate it from the blood. 



Yet the blood contains it and is highly infective, one 

 drop being sufficient, as a rule, to produce the disease. 

 There is also another remarkable feature about the infecting 

 agent, and that is it may be kept for years in blood without 

 losing its virulence, in spite of the fact that the blood is 

 putrid and swarming with bacteria. In this respect it is in 

 great contrast to all known poisons of infective diseases, 

 which generally die when kept any time apart from the 

 body, or in decomposing fluids. The blood may be kept in 

 an ice chamber or exposed to a temperature of 140° P. 

 without losing its virulence, but drying easily kills it. 



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