DR. LE(TEAR'S STOCK BOOK. 317 



been inherited, but it is a fact nevertheless, and one of almost 

 daily occurence, that the disease reaps its harvest among the off- 

 spring of consumptive parents. A weakly, consumptive parent 

 generally transmits a similar constitution, which is extremely 

 liable to the disease; and when it appears at an early age those 

 who believe in heredity think that there has been an "hereditary 

 infection" instead of an early "direct infection." Among the 

 wild herds of the plains consumption is practically unknown, 

 while among the cows of closely confined dairy herds it is quite 

 common. 



Prevalence, etc. Consumption, whether in man or the lower 

 animals, is a disease prevalent in *all civilized countries. In some 

 countries, such as the northern part of Norway and Sweden, on 

 the steppes of eastern Europe and Russia, in Sicily and Iceland 

 it is said to be quite rare. 



Where cattle are few, or absent, consumption is relatively less 

 in man. Dr. Burich pointed out the fact in countries like Aus- 

 tralia and the Sandwich Islands consumption among the people 

 did not exist until after dairy cattle were introduced. He also 

 called attention to the fact that consumption prevails in all coun- 

 tries where the dairy products are derived from cattle. He fur- 

 ther says: Morocco, where there are no European dairy cows, 

 is exempt from consumption, while in Spain and Portugal, where 

 dairying is carried on in European style, the disease exists. 



In most countries an effort is now being made to determine 

 more accurately the prevalence of the disease. Statistics show 

 that 75 per cent of old dairy cows in Germany have tuberculosis. 

 In Denmark nearly 40 per cent of the cattle have been found to 

 he consumptive. Some herds tested in the United States showed 

 that 32 per cent were affected. Some herds tested proved to be 

 entirely free from the disease. Of all the cattle killed in Ger- 

 many at the slaughter houses from 16 to 25 per cent have been 

 found affected. 



