PLEURO-PNEUMONIA CONTAGIOSA. 55 



the disease three months afterwards. The incubatory stage 

 of pleuro-pneumonia is from fifty to sixty days in duration. 

 The loss by death among affected animals varies from thirty 

 to eighty per cent., and those animals recovering are con- 

 siderably depreciated in value. The use of the flesh of an 

 infected animal as human food does not appear to exert any 

 prejudicial effect whatever ; at the same time, its use as 

 human food is not to be recommended. The disease is 

 ypread in various ways, as by trains, boats, etc. In England 

 large numbers of cattle have died of pleuro-pneumonia 

 during the last ten years, the same disease causing in 

 Holland a yearly loss of about fifty thousand cattle. 

 Animals that have suffered and recovered are free from a 

 second attack, according to all the recorded observations on 

 this point. This is strong evidence that the disease is a fever. 



Treatment. — As treatment is not advisable, prophylactic 

 measures alone will be referred to. As soon as the presence 

 of pleuro-pneumonia is detected, the diseased animal, or 

 herd of animals, should be strictly isolated from all other 

 cattle. The only proper method of dealing with pleuro- 

 pneumonia consists in stamping out the disease by a system 

 of extermination. It has been estimated by an eminent 

 authority that the American Government could effect this 

 object in the United States in the course of a year at a cost 

 of about fifteen million dollars, the chief difficulty being 

 that the various State laws interfere with this object, as 

 they conflict with each other; and the eradication of 

 pleuro-pneumonia can never be effected until the importance 

 of such an object is recognised by the national Govern- 

 ment and is made a national affair. 



Inoculation. — This has been practised for a number of 

 years, some experiments being practised twenty-five or thirty 

 years ago, but not with much success. The subject of 

 inoculation has, however, been revived and recently placed 



