48 MILK HYGIENE 



an exudate having a greater or less admixture of pus 

 cells. 



e. Udder tuberculosis. In many cases, the secretion 

 remains almost imperceptibly changed for a long period, 

 as only very small flakes are intermixed with it. Later 

 on, it decreases in quantity, grows thinner and contains 

 more flakes, and, finally, it is yellowish or reddish, se- 

 rous, contains clumps and flakes and becomes more like 

 pus. Chemically, the milk gradually undergoes the same 

 change as in cases of other forms of mastitis (Storch). 



f. Actinomycosis and tumors of the udder no doubt 

 cause changes in the appearance and the composition of 

 the secretion, but no investigations have been made on 

 these subjects. 



In mastitis, tuberculosis and actinom3'cosis of the 

 udder pathogenic bacteria are found in the milk; these 

 will be discussed later. 



VI EXCRETION OF FOREIGN MATTER 

 WITH THE MILK 



The milk glands may serve to excrete foreign mat- 

 ter which, in some waj', has found entrance into the 

 organ, just as the kidneys and other glands do. Such 

 an excretion does not take place to as great an extent as 

 was formerly believed, which, considered from a biologi- 

 cal standpoint, seems most natural, for the excretion of 

 foreign matter would prove a great danger to the young 

 animal dependent on its mother's milk for food. Yet 

 there are not a few, and sometimes veiy harmful, sub- 

 stances that are excreted from the organism through the 

 udder and, therefore, it is one of the problems of milk 

 hygiene to prevent the milk of such cows as are affected 

 in this way, from being used, just as the physician must 

 always consider, in the treatment of mothers and wet 

 nurses, what influence medicines to be given may have 

 on the nursing child. 



