44 MASTITIS OF THE COW 



Cows. — No. 1 : Fourteen days after parturition a milch 

 cow was injected in one teat with 10 c.c. of a very virulent 

 bouillon culture of streptococci which had been isolated 

 from a case of mastitis. The culture was controlled for 

 pathogenicity on two mice, one of which died in one day, the 

 other in two days. 



On the day after the infection the body temperature 

 was 41.1° C. (ca. 106° F.) . The cow lay down, sweat, and 

 refused to eat. The infected quarter was greatly swollen 

 and painful to pressure. The skin was tight and doughy 

 to the touch. The milk of the quarter was diminished in 

 quantity and presented a yellowish purulent appearance. 

 Microscopically it was rich in streptococci. 



Two days after the infection the fever had subsided. 

 The appearance of the quarter was the same. The milk 

 of the quarter was still less in quantity and consisted of a 

 yellowish turbid serum plus yellow fibrin clmnps. Numer- 

 ous streptococci were found in the fibrin. Five days after 

 the infection the swelling of the quarter was greatly in- 

 creased, stone hard and somewhat less sensitive. The quan- 

 tity of milk from the quarter was insignificant. The milk 

 was purulent and consisted of yellow turbid serum plus 

 yellow clumps of fibrin which contained few streptococci. 



One month after the infection this quarter and its milk 

 showed the same appearance. The animal was then 

 slaughtered. 



Autopsy. — The infected quarter was firm and very 

 much swollen. The incision was somewhat dry (absence 

 of milk) and the cut surface was smooth, yellowish-gTay 

 and firm. The lobuli were small and showed no milk points 

 (cross sections of fresh tubuli). Upon pressure yellow 

 cylinders of fibrin were expressed. In addition five necrotic 

 nodules were found which were about the size of a walnut, 

 rounded, sharply circumscribed, firm and surrounded by 



