1919] VETERINARY MEDICINE. 87 



Studies in bovine mastitis. — II-IV, V. S. JONES (■four. Expt. Med., 28 

 (1918), Noa. 5, pp. ■■',.; iff} .• 6, pp. 721-755, 755-748).— In continuation of studies 

 i revloualy aoted (E. s. EL, 39. p. 800), the author first takes up the relation of 

 hemolytic Btreptococci to odder Infections. Ho finds that "hemolytic strep- 

 tococci produce more »>r less severe inflammations of the udders of cows. Fre- 

 quently Infected quarters arc swollen, firm, hot. and tender. In a number of 

 instances it has not been possible to detect gross changes In the mammary gland. 

 The streptoccoei isolated from the invaded quarters have produced clear zones 

 of hemolysis immediately surrounding the colonies when cultivated in ho 

 blood agar plate cultures. The hemolytic zone has varied from a clear, narrow 

 band up to zones 1.7 to 2 nun. wide. 



"When the streptococci are classified according to their action upon carbo- 

 hydrates, they fall Into two broad groups; the larger consists of i!> strains 

 fermenting dextrose, lactose, saccharose, maltose, and salicin, and a smaller 

 number, comprising 10 species, produces acid in dextrose, lactose, saccharose, 

 I ad maltose and fails to ferment salicin. One of the nonsalicin fermenting 

 strains did not attack saccharose. In no instance was acid production noted in 

 raffinose, Inulin, or mannite. 



"All streptococci except three were agglutinated by an antiserum obtained 

 from a rabbit immunized with a single strain. 



" Freshly isolated cultures when injected intravenously into rabbits possess 

 but slight pathogenicity. Localizations in the joints occurred in two instances. 

 The others either failed to affect the general condition of the animals or pro- 

 duced only a slight febrile reaction." 



Discussing infection of the udder with micrococci and other microorganisms, the 

 author finds that " aside from the streptococci, micrococci have been the next most 

 frequent group of organisms isolated from inflamed udders. They produce va- 

 rious types of disease. Some give rise to only a mild catarrh of the larger milk 

 ducts and cistern, while others produce more or less severe parenchymatous in- 

 flammation. On the whole, the prognosis is more favorable with micrococci in- 

 fection than with that associated with streptococci. Cases of considerable se- 

 verity have, however, been attributed to staphylococci. 



" Micrococci similar in many respects to those associated with mastitis have 

 I een found to occur in the normal udder. This has led Savage to question their 

 true etiological significance. In many instances micrococci may gain access 

 to the udder and produce slight disturbances that are entirely overlooked. Even 

 more severe changes may follow infection. After recovery the organisms still 

 remain in the milk. This was observed in the case of cow 60 infected with 

 staphylococci. 



"One frequently observes the elimination of streptococci from the udder 

 even after apparent recovery from an attack of streptococci mastitis. Doubtli s- 

 streptococci and micrococci observed in these udders would be classed as belong- 

 ing to the normal flora. Even though micrococci do occur in supposedly normal 

 udders, Evans has shown that many are pathogenic for rabbits. The introduc- 

 tion of these organisms into the udders of nonresistant individuals might well 

 give rise to more or less Intense Inflammation. The multiplication would doubt- 

 less be rapid until resistance had been established. 



"In addition to the micrococci two other groups of rod-shaped organisms have 

 been found associated with udder inflammation. In two instances Bacillus coli 

 has been isolated from cases of mastitis and in another B. lactis oerogenes. In 

 four, tiny motile Gram-staining microorganisms have been obtained in pure 

 culture. Two of these strains . . . have been identified as B. pyogenes." 



104028°— 19 7 



