516 BOARD OF AGRICULTURE. [Pub. Doc. 



cases comes on in the later stages, when the virus is distributed by 

 the blood from some disintegrated earlier focus of disease. Primary 

 tuberculosis of the udder, that is, infection from without, has not yet 

 been established definitely, and is probably of very rare occurrence. 

 When the disease has started in the udder itself, tubercle bacilli may 

 be discharged in the milk in large numbers and for long periods of 

 time. The smaller the herd, in such a case, the more dangerous the 

 eutire milk becomes, because of the concentration of the virus. 



Udder tuberculosis is thus a most serious danger, the importance 

 of which canuot be too strongly urged. Fortunately, it is rare. The 

 writer has encountered, among two hundred infected animals, only 

 one case of udder disease, and sixteen others which, according to the 

 post-mortem studies, may have shed at one time or another tubercle 

 bacilli into the milk in small numbers, but which had no recog- 

 nizable disease of the udder itself. The large percentage of udder 

 tuberculosis reported by several writers lately is incompatible with 

 all former statistics, and indicates either an unprecedented condition 

 in certain localities or else an error in diagnosis. The stock owner, 

 in the absence of proper dairy or other official inspection, is under 

 serious moral responsibilities to remove from his herd those animals 

 in which there is even a suspicion of udder tuberculosis. Any udder 

 which is found to increase slowly in size without any indication of 

 inflammatory processes, recognizable by the presence of heat, pain 

 and redness, and which becomes very firm without showing at first 

 any alteration in the appearance of the milk, should be regarded as 

 infected, the cow promptly segregated, and the entire milk rejected 

 until a diagnosis can be made by a veterinarian. 



In view of the fact that tuberculin does not discriminate between 

 dangerous and harmless cases, the public health problem as it pre- 

 sents itself in practice is simply this : what shall be done with all the 

 cattle which give the tuberculin reaction, in order that we may catch 

 and destroy the ten per cent, of slightly and temporarily dangerous 

 cases among them, or the one per cent, of serious cases? Some of 

 the dangerous cases are so far along in the disease that they are easily 

 detected without the aid of tuberculin, but this is by no means true 

 of the majority. The situation certainly demands a most rigid peri- 

 odical inspection of all animals furnishing milk to consumers, the 

 prompt removal of all suspicious cases, and, above all, a more 

 thorough control of the dairy in the interest of public sanitation. 



In 1890 a Royal Commission was appointed by the govern- 

 ment of Great Britain, "to inquire and report what is tke 

 effect, if any, of food derived from tuberculous animals on 



