26 MASTITIS OF THE COW 



Not infrequently, however, the infection is progressive 

 in spite of the inflammation. The infection spreads fur- 

 ther to the healthy lobuli and induces a new primary lesion 

 with its subsequent inflammatory reaction. 



The course therefore is more protracted. The condition 

 may last from a month to a year and the terminal result 

 is a diffuse sclerosis and atrophy of the parenchyma. 



The functional capacity of the udder becomes more or 

 less reduced following the inflammatory process induced 

 by the milk-infection. This deficiency may be overcome, 

 however, through vicarious hypertrophy of the unaltered 

 parts of the udder. 



STROMA-iNFECTioN llnterstiticd Mastitis^ 



Definition. — Stroma-infection or interstitial mastitis 

 is that infection of the udder in which the infectious or- 

 ganisms are only found in the stroma or interstitial con- 

 nective tissue. 



The pathogenic organisms invade the lymph spaces of 

 the intralobular connective tissue. 



Since the connective-tissue system binds the different 

 quarters of the udder together, the stroma-infection can 

 spread from one place to the neighboring tissue, while the 

 milk-infection, on the other hand, is confined to the infected 

 quarter. 



The stroma-infection may be divided into two principal 

 groups : 



1. Stroma-infection of an acute character. 



2. Stroma-infection of a chronic character. 

 Stroma-infection of an Acute Character [Acute 



Interstitial Mastitis]. — These cases depend upon quickly 

 acting infectious organisms, which in their active way may 

 produce an acute, never typically chronic, process. 



The point of infection is one or more wounds. The 

 blood is seldom the source of infection and this infection 



