MASTITIS 93 



changes in milk secretion during this disease, nor have 

 the actinomyses or ray fungi yet been found in milk, 

 in which they probably occur. Man may be infected 

 through the digestive canal (the mouth and intestines), 

 just as cattle are, and on this account the possibility of 

 contagion through milk should not be disregarded. 

 Therefore, milk from cows affected with udder actino- 

 mycosis (which, however, is not often diagnosed in liv- 

 ing cows) should not be used as food for man. 



h. Inflammation of the udder (mastitis). The forms 

 of inflammation of the udder occurring in the cow may 

 be divided into the following principal classes, which 

 differ chiefly according to the grade of inflammation, 

 the extent to which the milk secretion is checked and the 

 character of the exudate : 



1. Mucous catarrh; 



2. Purulent catarrh; 



3. Parenchymatous, purulent mastitis, ultimately 

 accompanied by abscesses ; 



4. Gangrenous mastitis. 



These forms cannot always be distinctly separated. 

 The changes caused through inflammation of the udder, 

 in the chemical composition of milk were described 

 above. 



The various forms of mastitis are of microbic origin. 

 There are many kinds of bacteria which, if admitted 

 to the milk cistern, may cause inflammation of the glands 

 and, upon examination of the spontaneous cases, quite a 

 large number of mastitis bacteria have been found, 

 chiefly such as cause inflammation elsewhere in the 

 organism. By far the most cases of udder inflammation 

 arise from bacteria which belong to one of the following 

 groups : 



1. Streptococci, which usually cause chronic mucous 

 (slimy) or purulent catarrh, ending with atrophy of the 



