vi DISEASES OF THE COW 109 



was the variety which they called Streptococcus anginosus, 

 while the other was identical with Streptococcus pyogenes. 

 Comparing the two types most commonly met with in the 

 bovine and human conditions the Streptococcus mastitidis 

 and Streptococcus anginosus it was found that, morphologic- 

 ally and culturally, they were quite indistinguishable even 

 when the different sugar-alcohol tests were employed. In 

 addition, the commonest cultural deviations from the type 

 were- the same in both cases. As regards their pathogenicity 

 towards the lower animals, however, they show distinct 

 differences. Streptococcus mastitidis possesses low virulence ; 

 occasionally a local abscess is produced, but, as a rule, no 

 pathogenic action is manifested towards mice or guinea-pigs. 

 The Streptococcus anginosus type, on the other hand, is possessed 

 of considerable pathogenic action, subcutaneous inoculation 

 into mice frequently causing the death of the animal. The 

 distinction is one of degree rather than kind, and otherwise- 

 the close similarity is very interesting. Further comparison 

 is only possible along the lines of their specific properties. 



Can the mastitis streptococci, by inoculation upon the 

 human throat, set up inflammatory action ? Will the udders 

 of cows when inoculated with streptococci from cases of human 

 disease become infected and mastitis result ? Both problems 

 were experimentally investigated. The second question was 

 studied in a series of experiments upon goats. Twenty-two 

 separate experiments were carried out in which the teats were 

 infected with pure cultures of different organisms. The results 

 in the twenty experiments in which pure cultures of recently 

 isolated streptococci were used were as follows : The three 

 streptococci from mastitis cases in cows all set up mastitis in 

 goats. Of two streptococci from sore teats one set up a very 

 severe mastitis, but the other was without effect. A strepto- 

 coccus very common in, and isolated from, cow dung also pro- 

 duced no visible effect. Thirteen streptococci of human 

 origin, one from a healthy throat, six from cases of sore throat 

 .(2 being scarlet fever cases, and 4 ordinary tonsillitis 

 cases), and four isolated from other human diseases, all failed 

 to produce mastitis in the goat. In the remaining two cases, 

 both streptococci not obtained from sore throats, distinct 

 inflammatory reaction and some degree of mastitis resulted. 



