PATHOLOGIC LESIONS 207 



Streptococcus pyogenes bovis. 



Staphylococcus pyogenes bovis. 



Bacillus pyogenes bovis. 



Bacillus liquefaciens pyogenes bovis. 



Bacillus crassus pyogenes bovis. 



Streptococcus Pyogenes Bovis. This organism appears as small cocci 

 arranged in long chains; they grow particularly long in nutrient 

 bouillon. It does not liquefy gelatin, nor grow on potatoes. Bouillon 

 first becomes cloudy, later a scanty sediment forms on the bottom and 

 the fluid again becomes clear. It is not pathogenic to guinea-pigs 

 and rabbits. 



FIG. 115 



Streptococcus pyogenes bovis, pure culture obtained from the uterus of a cow. X 1000. 

 (From preparation of Dr. L. E. Day.) 



The Staphylococcus Pyogenes Bovis. The organism is smaller than 

 the Staphylococcus pyogenes aureus of man and the horse. It 

 does not grow well in artificial cultures, and soon dies out. It does 

 not liquefy gelatin, while the Staphylococcus pyogenes aureus does. 

 Cultures on artificial media show a very low degree of virulency. 



BACILLUS PYELONEPHRITIDIS BOVIS. 



This bacillus is an important pus producer in cattle, frequently 

 causing a pyelonephritis, known as pyelonephritis bacillosa bovum. 

 The disease is generally observed in cows shortly after parturition, 

 particularly in cases of retention of the placenta. Occasionally pyelo- 

 nephritis in cows is also caused by the common Staphylococcus and 

 by the Bacillus pyocyaneus. 



Pathologic Lesions. Pyelonephritis bacillosa bovum is an inflam- 

 matory, purulent, or diphtheritic necrotic process, characterized by 

 great enlargement of one or both kidneys, with enlargement of the 



