3/6 AGRICULTURAL BACTERIOLOGY. 



knife will be on its surface, cooking will almost always render 

 it harmless, unless the infection is deep-seated. For these 

 reasons the flesh of animals slightly infected with this dis- 

 ease need not be condemned as food. A method of dealing 

 with this question, adopted in Germany, is an excellent one, 

 though it would hardly be satisfactory in all countries. All 

 meat is inspected. Carcasses which are very badly infected 

 with tuberculosis are destroyed. Those which are only slightly 

 infected have all the infected portions removed and the flesh is 

 sold freely. Those which are moderately infected have their 

 flesh sold upon what is called the " Friebank," a special part 

 of the market where infected meat is sold, and the purchaser 

 is given to understand that it is suspicious and not safe to eat 

 without thorough cooking. In the United States flesh of 

 slightly infected animals is passed by the inspectors and sold 

 freely in the market. Whether such meat is a source of dan- 

 ger is very doubtful. At all events no evidence is at hand to 

 indicate that human tuberculosis is caused by the eating of 

 such flesh, although the lack of evidence means little, since 

 evidence, from the nature of the case, would be very difficult 

 to obtain, even if such infection did occur. It is universally 

 admitted that the actual danger from this source is very small 

 and perhaps does not exist at all. 



Milk. The problem of the use of milk from tuberculous 

 animals is a more difficult one to settle, at least for the United 

 States, where the people will not adopt the habit of pasteur- 

 izing milk. The milk of tuberculous cattle does not always 

 contain the bacilli and it is an unsettled question whether it 

 will ever contain them unless the disease be located in the 

 udder. At all events, cows having tuberculous udders (some- 

 thing less than one per cent.) will produce milk infected with 

 tuberculosis bacilli. That these bacilli are active and vigorous 

 is proved by thousands of experiments which have shown that 

 such milk is capable of producing tuberculosis in guinea-pigs. 



