Tuberculosis. 543 



"has opened through the walls of the vessels (capillaries), so that 

 the infecting bacilli can pass into the blood in a continuous 

 stream. The pus and other microbes, in complex infections, 

 hasten this degeneration and contribute to generalization of 'the 

 tubercle and emaciation. The transient infection of the blood 

 -with the pure tubercle bacillus does not, however, lead to emacia- 

 tion and marasmus, and hence the frequency of high condition in 

 spite of extensive tuberculosis. 



Ostertag gives the following as indicating blood infection : 

 ' ' When with emaciation there is evidence of recent blood infec- 

 tion, enlargement of spleen and all lymph glands, miliary 

 tubercles of the lungs, liver, spleen and kidneys." In the 

 absence of these indications, though there may be numerous old- 

 standing tubercles, caseated, calcified or sclerosed, he considers 

 that there is no reason to dread infection of the blood and carcass. 

 Even a tuberculous intermuscular gland does not, in his opinion, 

 condemn the adjacent muscle. When vomicae (caverns) are 

 present in the lungs and internal organs the flesh may still be 

 used ' ' if embolic tubercles of different ages, indicating repeated 

 eruptions of tubercle bacilli into the blood stream, are absent from 

 the spleen and kidneys. ' ' This meat is, however, to be sterilized 

 before marketing (Ostertag). 



The United States Bureau of Animal Industry orders the de- 

 struction of all cases of ' ' extensive or generalized tuberculosis ; ' ' 

 ' ' any disease or injury causing elevation of temperature or affect- 

 ing the system of the [animal to a degree which would make the 

 flesh unfit for human food ; ' ' also ' ' any organ or part of a car- 

 cass which is * * * affected by tuberculosis * *. " 



In most countries of Europe even emaciated animals are used 

 for food for animals or even man, provided the wasting is not too 

 extreme. The carcass must, however, first be subjected to a 

 temperature of 230° F. for a period of three hours. This is sold 

 in a special market as low priced meat and labelled as such. 

 Ordinary cooking does not always sterilize, as Martin and Wood- 

 head, like Vilemin, found living bacilli in the centre of a cooked 

 six-pound roast. 



Immujiization. Attempts have been made to immunize the 

 system against tuberculosis. The most notorious is that of Von 

 Behring who claims that in three months, by three successive 



