240 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



the nearest biological laboratory, where a positive diagnosis can be 

 made within thirty-six hours by the histological examination of the 

 plexiform nerve ganglia, and within two or three weeks by the intra- 

 cerebral inoculation of rabbits with an emulsion of the brain of the 

 suspected animal. 



Treatment. This is useless after the first appearance of symp- 

 toms. When, however, a wound inflicted by a rabid animal can be 

 discovered, it should be immediately cauterized or even completely 

 extirpated, care being taken to cut entirely around the wound in the 

 healthy tissues. For cauterizing the wound, fuming nitric acid, the 

 hot iron, and 10 per cent solution of zinc chloride are the most effica- 

 cious. To afford an absolute protection, this should be done within 

 a few moments after the bite has been inflicted, although even as late 

 as a few hours it has been known to thwart the development of the 

 disease. 



Pasteur has originated and perfected a system of preventive in- 

 oculation against this disease which has greatly reduced the mortality 

 in human subjects. Its application to animals, however, is more dif- 

 ficult, requiring considerable time and expense, and is therefore only 

 economically applicable in cases where very valuable animals are bit- 

 ten by dogs known to be mad. Sanitary regulations which seek to 

 control effectively the disease by exterminating it among dogs are 

 most likely to prove successful. The measures which are adopted to 

 this end can not be discussed in this place, but it is a striking fact 

 that where the muzzling of all dogs has been rigidly enforced, as in 

 England and in certain German districts, the disease has been prac- 

 tically stamped out. 



TUBERCULOSIS. 



Tuberculosis is a widespread disease affecting animals and also 

 man. Human beings and cattle are its chief victims, but there is no 

 kind of animal that will not take it. Hogs and chickens are quite 

 often affected; horses, sheep, and goats but seldom, while cattle are 

 the most susceptible of all animals. 



Nature of the Disease. Tuberculosis is contagious, or catching. 

 It spreads from cow to cow in a herd until most of them are affected. 

 This may not attract much notice from the owner, as the disease is 

 slow to develop and a cow may be affected with it for several months 

 and sometimes years before any signs of ill health are to be seen. 



This slow development is the chief reason for the great loss it 

 causes to the farmer. He does not suspect its presence in his herd 

 until perhaps a large number are diseased. If the disease developed 

 rapidly and caused death in a few days, the owner would soon take 

 steps to check its progress and protect the rest of his herd. Tuber- 

 culosis is slow and hidden in its course and thus arouses no suspicion 

 until great damage is done. 



History. Where did tuberculosis come from ? We do not know. 

 History records it from the earliest times. Over a century ago its 

 contagious nature was suspected and many facts were recorded to 

 prove that it must be catching. Doctors differed about it and for a 

 long time the question was hotly disputed. Finally it was settled by 



