14 



Anatomy, Pathology and Histology of the Mammary Gland. 



commencing at the base of the gland, and finally during the end of 

 lactation in the entire udder. Epithelial cells are thrown off, the 

 alveoli become fewer, smaller, and irregularly distended, the con- 

 nective tissue increases, and cellular infiltration starts under and 

 between the epithelial layers. The epithelium contains no fat 

 globules, it is sharply bordered towards the alveoli and the pro- 

 toplasm becomes pale. Finally the last remains of the secretions 



Fig. 9. 



b. 



a. 



b. 



a. 



Acute streptococcic mastitis of sheep. 1 X 1000. 



(a-1) Blood capillaries. 2. Thrombosis by disseminated streptococci, (b) Glandular 



alveoli, with clumps of streptococci. (c) Migration of leucocytes into 



the infected alveoli. 



disappear, the plasma cells and leucocytes taking care of the 

 resorption. 



At the end of this process the gland is at rest, and the cow is 

 dry. 



Of course these processes are not always so schematically uni- 

 form as they have been described. During the entire lactation 

 period, colostrum-forming, and retrogressing lobules may be ob- 



