Structure of the Tissue. 



served; likewise certain parts of the udder may remain in secre- 

 tion during retrogression until storing of the secretion, leucocytic 

 resorption activity and connective tissue proliferation cause them 

 to cease their activity. 



(b) Pathological Appearance. 



Any kind of irritation of the gland, such as stasis of the milk, 

 especially in chronic catarrhs and inflammations, may result in the 

 most varied kind of pathological conditions, either in mixed form 

 or individually. The manifestations vary, depending upon 

 whether degeneration and destruction of the tissue, or reparation 

 and recovery gain the predominance. 



Sometimes desquamation of epithelium, with or without fatty 

 degeneration, occurs together with cellular infiltration of the in- 

 terstitial connective tissue and capillary engorgement as the only 

 indications of inflammation ; or, on the other hand, the changes in 

 the interstitial parts may be very pronounced, while the changes 

 of the parenchyma may be less prominent. The inter- and intra- 

 lobular connective tissue extends forming thick indurations, from 

 which the separated epithelium is compressed to small necrotic 

 nests. In other stages of inflammation the cellular infiltration of 

 the tissue predominates. The alveoli and the milk ducts are 

 plugged up thickly with leucocytes, and dilated with the pus. In 

 highly acute inflammations the rapid breaking down of cells, de- 

 struction of epithelium, serous and cellular infiltration of the 

 tissues even to their dissolution, are the principal manifestations. 

 The ducts and the alveoli are inundated with serous, bloody co- 

 agulated masses. 



In stasis of the milk, and in all inflammatory manifestations, 

 especially of the acute form, the alveoli contain hyalin and con- 

 crement arranged in layers, in addition to inflammatory cells and 

 broken down cellular products. 



