THE GENUS STREPTOCOCCUS 167 



tive agent in Malta fever was thought by him to be a 

 coccus, and in its general cultural relations it resembles 

 Str. pyogenes. Babes (1903) claims that the "M. nieli- 

 tensis" of Bruce is a short bacillus. The biochemical 

 properties "of the organism, and the relations of its serum 

 reactions to those of other forms, are not sufficiently 

 worked out to make its position clear. 



If the pneumococcus is placed in the genus Diplococcus, 

 six of Andrewes and Horder's types remain as species 

 of the genus Streptococcus. It is probable that further 

 study of biochemical properties may reveal other im- 

 portant centers of variation. In a suggestive paper, 

 Sieber-Schoumoff (1892) pointed out two such charac- 

 teristics, which might be of value in the differentiation of 

 streptococci. She found that certain strains, when cul- 

 tivated in sugar broth, formed optically inactive lactic 

 acid, while others produced the levo -rotary compound. 

 Of the latter group, some cultures showed the power of 

 forming salicylic acid in broth containing salol. Hashi- 

 moto (1901) has described a streptococcus and a micro- 

 coccus (apparently a strain of Albococcus pyogenes) 

 both of which formed pure dextro-rotary lactic acid 

 from milk-sugar. From Hashimoto's review of previ- 

 ously described organisms, it appears that the production 

 of dextro-rotary acid has been recorded among the cocci 

 in four cases, and that of levo-rotary acid only once, by 

 Leichmann. 



In our own work we attempted to divide the streptococci 



