CHANGES IN THE SECEETION 47 



and fibrin. The milk secretion decreases more or less 

 quickly while the pus cells and fibrin increase in number 

 and, finally, the secretion is replaced by a viscid, whitish 

 or yellowish purulent exudate or by a quantity of yel- 

 lowish serous exudate which contains clumps of pus and 

 fibrin. In many cases, the udder shrinks and the exuda- 

 tion ceases without the return of the milk secretion; in 

 other cases, milk secretion returns either during the 

 same period of lactation or after the birth of the next 

 calf. In catarrh of the udder, lactose decreases in quan- 

 tity while the other ingredients — except ash — undergo 

 no quantitative change in the mildest cases. Among the 

 ash ingredients, phosphoric acid, lime, magnesia and 

 potash decrease materially in quantity, while sodium 

 chloride occurs in more than normal quantity. In cases 

 when the secretion is mixed largely with exudate, the 

 quantity of lactose still further decreases and the casein 

 content drops, while albumin and globulin (also fibrin) 

 increase. 



c. Parenchymatous mastitis. The changes in the 

 secretion correspond essentially with the changes in 

 purulent catarrh, but they occur very suddenly and may 

 disappear as rapidly. The chemical analysis shows 

 changes similar to those in catarrh ; the lactose often dis- 

 appears entirely, while the albumin and globulin in- 

 crease greatly in quantity. The fats may increase or 

 decrease, the salts change as in catarrh. 



d. Gangrenous mastitis. The real milk secretion 

 ceases while a bloody-serous liquid is secreted which, on 

 account of the existence of bacteria of putrefaction, is 

 frequently mixed with gas and has the odor of putre- 

 faction. 



The chemical changes that take place in mastitis 

 are mainly traced to partial or entire cessation of the 

 real milk secretion and to a simultaneous elimination of 



