Acute Maniniitis 953 



septicsemia, which may emanate from the disease processes in 

 the glands. 



An incision through a milk gland recently attacked by mam- 

 mitis, reveals engorgement, injection and hemorrhages in the 

 parenchyma. The milk canals contain abnormal secretions, usu- 

 ally flocculent in character, due to clots of casein. The groups 

 of acini upon the cut surface appear as small yellow clumps. 

 Serous or sero-sanguineous fluid may be pressed from the cut 

 surface. 



If the disease assumes the catarrhal type, and limits its rav- 

 ages chiefly to the epithelium of the gland, the milk cistern and 

 milk ducts usually contain muco-purulent or purulent secre- 

 tions. The accumulated secretions may be thin and watery v\nth 

 caseous clots floating in them, stringy and tenacious, or purulent 

 and fetid. 



Sometimes the disea.se may be limited to the milk cistern, and a 

 catarrhal inflammation ensue with discharge of the pus through 

 the teat orifice ; or the teat orifice may become blocked, con- 

 verting the cistern temporaril}^ into an abscess cavity, which 

 eventually ruptures by re-opening of the milk orifice, and the dis- 

 charge of the accumulated pus follows. Such an abscess tends to 

 cause permanent atresia of the larger milk ducts and, preventing 

 the escape of milk into the cistern, produces engorgement of 

 that portion of the gland from which the affected duct normally 

 serves as an outlet. Later the engorgement destroys the secre- 

 tory power of the part, and there may remain for a time an im- 

 prisoned volume of milk — a " milk cj'st." Catarrhal inflamma- 

 tion of the milk cistern may lead to atresia or adhesions in any 

 part of the cavity. Sometimes the entire milk cistern becomes 

 occluded, the cistern walls adhere from the base to the apex of 

 the teat, and even though the gland itself may escape destruc- 

 tive inflammation, it is later doomed to pressure atrophy from 

 the compression of the imprisoned milk. Such adhesions occur 

 most readily in the dry cow or heifer, when the changes named 

 are not interrupted by a constant flow of milk into the cistern. 



When the catarrhal inflammation extends to the smaller milk 

 ducts and acini, the secretory epithelium is more or less injured 

 or wholly destroyed, while the cavities of the acini become oc- 

 cluded with exudate. Later the glandular tissue may undergo 



