EXAMINATION FOR STREPTOCOCCI 



155 



finose, mannite, lactose, and salicin broths for deterinination of 

 acidity, in milk for coagulation, and to blood agar plates for 

 haemolysis. A virulence test is also desirable, but in considering 

 the results obtained due regard must be given to the dosage and 

 method of inoculation. A quantity of broth that is sufficient to 

 kill the test animal in three days when injected intravenously 

 might not produce more than local symptoms when given sub- 

 cutaneously, and similar conditions apply to the dosage. For 

 guinea pigs 1 c.cm. of a forty-eight hour broth cultm-e and for 

 mice 0.5 c.cm. of a twenty-four hour culture have been found 

 to give satisfactory results when injected into the peritoneal 

 cavity. 



The biochemical characteristics should be determined 

 quantitatively by Winslow's method ^^ if the best results are to 

 be seciu'ed. 



Table LIX 

 BIOCHEMICAL CHARACTERS OF PRINCIPAL TYPES OF 



STREPTOCOCCI. (BBOADHt7BST) 



X indicates that test substance is fermented with production of acid and without 

 gas formation. 



® indicates that test substance is occasionally feimented. 



