96 THE MILK QUESTION 



bacilli appear in the milk when this condition is present. 

 It is estimated that about one to two per cent of all cows 

 with tuberculosis have udder tuberculosis. It is usually the 

 left hind quarter of the udder that is involved. Sometimes 

 the cow has tuberculosis of the udder, while no other part 

 or organ is involved. As a rule tuberculosis of the udder is 

 secondary to tuberculosis of some other gland or tissue. 

 The disease, when it is fully developed in the udder, may 

 usually be recognized by feeling the hard inflammatory 

 nodules and by noticing the abnormal appearance of the 

 secretion from the diseased quarter. In udder tuberculosis 

 the appearance of the milk remains unaltered for a long 

 period, although it contains tubercle bacilli. Only very 

 small flakes are intermixed with it. Later on it decreases in 

 quantity, grows thinner, and contains more flakes. When 

 fully developed, the secretion obtained from the diseased 

 quarter no longer resembles milk, but is a slimy, muco- 

 purulent, creamy, or cheesy substance. A minute fraction 

 of a drop of this secretion may be sufficient to cause fatal 

 tuberculosis in a guinea-pig. The other three quarters of 

 the udder may not be involved at all. 



The milk from a tuberculous udder of one cow may be 

 sufficient to contaminate seriously the milk from a herd of 

 twenty-five or thirty cows. In a certain instance Ostertag 

 found that one millionth of a cubic centimetre of the se- 

 cretion from a tuberculous udder was sufficient to cause 

 tuberculosis in a guinea-pig. A child would drink in six 

 ounces an enormous dose in such a case. The tubercle 

 bacilli in the secretion of many a case of tuberculosis of the 

 udder are quite as numerous, under the microscope, as they 

 are in tuberculous sputum. 



Schroeder has pointed out the danger of infecting milk, 

 from cows having pulmonary tuberculosis, through the 

 faeces. Milk obtained by the ordinary methods contains an 

 appreciable quantity of cow faeces; sometimes excessively 

 large amounts. This is one of the ways in which tuber- 



