174 CLINICAL BACTERIOLOGY AND 



to the practitioner who may be called upon to diagnose 

 a case of tuberculosis. 



Tuberculosis of the Udder. 



This condition may appear as a single nodule, located in 

 one quarter, giving, when manipulated, a feeling that the 

 surface is irregular, or it may be composed of a collection of 

 nodules, giving the mass considerable dimensions and surface 

 irregularity. These growths are hard, firm, and not painful 

 when pressed upon. 



When the growth is confined to one quarter, the adjacent 

 healthy parenchyma of the gland often atrophies, the nodule 

 thereby assuming a more or less pendulous condition. 



Where the udder is extensively involved, the lymphatic 

 glands on the supero-posterior aspect are enlarged so much 

 that they can often be seen and invariably felt. The pro- 

 gress of the disease is usually slow, and in some cases a 

 kind of parenchymatous mammitis develops, due perhaps 

 to some form of secondary infection taking place. 



The udder may show the nodules for months, and yet to 

 all appearances the milk may be quite normal, and upon 

 careful examination no bacilli may be detected. They 

 may, however, be present, and failure to detect them may 

 be due to the fact that they are eliminated in limited 

 numbers. On the other hand, the organ may appear to be 

 quite healthy, and yet tubercle bacilli will be found in the 

 milk, evidently coming from some infective centre in the 

 system. Also it may be well to note that the udder in these 

 cases perhaps harbours the disease in an invisible form, there- 

 by accounting for the milk contamination. At some period, 

 however, an alteration in the quality of the milk will take 

 place. As time goes on it will become thin and watery, 

 and blue in colour ; later it will curdle, and then a mixture 

 of clot and dirty light red water is all that can be milked 

 off, and finally nothing more than a dirty grey or greyish- 

 red watery fluid appears. 



