ROBERT S. BREED 387 



No. 19" which is described so clearly and his gelatin-stab culture figured so accurately 

 that there can be little question but that he also had the sour-milk streptococcus. 

 Freudenreich/ working in the same field, early found an organism for which he used 

 the descriptive name of "der ovaler coccus." In 1899 and 1902 he recognized this or- 

 ganism as identical with Leichmann's Bacterium lactis acidi, though he confused the 

 names badly. 



Certain things about the souring of milk still puzzled bacteriologists, for, as 

 Leichmann had shown, the sour-milk organism produced dextro-rotary lactic acid 

 while the acid in sour milk was generally reported as inactive. Kozai' was the first to 

 show the explanation of this phenomenon when he found that the acid in milk soured 

 at room temperatures was of the dextro-rotary type while that found in milk soured at 

 body temperature was of the inactive type. He likewise showed that Leichmann's or- 

 ganism grew better at room temperature, while Hueppe's organism grew better at 

 body temperature. Not satisfied with the abundance of names already proposed for 

 the sour-milk organism, he changed its name to Bacillus acidi paralactici. 



Because this name is similar to Micrococcus acidi paralactici Nencki and Sieber^ 

 given to a very similar organism, which the latter authors state is possibly identical 

 with Grotenfelt's Streptococcus acidi lactici, Nencki and Sieber's name is sometimes 

 given in the list of synonyms of Streptococcus lactis. While it is described as a strepto- 

 coccus occurring in twos, threes, and fours that produces dextro-rotary lactic acid, 

 their description of its habitat in guinea-pig lesions, presence of capsules, pathoge- 

 nicity for guinea pigs, and other characters place it in the group of indefinitely 

 described streptococci doubtfully identified as Streptococcus lactis. 



The generic relationships of the organism not yet being clear, the period following 

 1896 saw several changes in the names already proposed. Thus Chester-i in 1897 

 changed Kruse's name to Bacterium lacticus, and Migula^ in 1900 used the more cor- 

 rect form Bacterium lacticum. The latter likewise gave the name Bacterium truncatum 

 to Adametz's "Bacillus No. 19." This binomial should be regarded as a synonym of 

 Streptococcus lactis. 



Beijerinck*" meanwhile introduced the name Lactococcus lactis as a more accurate- 

 ly descriptive name, apparently without any reference to the fact that lactis was the 

 specific name used by Lister. If the sour-milk streptococcus is ever placed in a genus 

 separate from the pyogenic streptococci, it should be noted that the generic term 

 Lactococcus has priority. 



Kruse^ in 1903, with a clearer insight into the matter, caught the resemblance be- 

 tween the sour-milk organism and Streptococcus lanceolatus (pneumococcus), and 

 other related streptococci and changed the name he had previously given to Strepto- 



' von Freudenreich, E.: Cenlralbl. f. BaklerioL, Abt. II, i, 168. 1895; 5, 241. 1899; 8, 674. 1902. 



* Kozai, Y.: Ztschr.f. Hyg. u. Infcklionskrankh., 31, 337. 1899. 



J Nencki, M., and Sieber, N.: Monatschr. f. Chem., 10, 532. 18S9. 



''Chester, F. D.: Delaivare Agric. Exper. Sta. (Neimrk) gth Ann. Rep., pp. 53-145. 1897. 



5 Migula, W.: op. ciL, 2, 405. Jena, 1900. 



^Beijerinck, M. W.: Arch, neerl. d.sc. exact, et nat., Harlem (2d ser.), 7, 212. 1901. 



' Kruse, W.: Cenlralbl. f. BaklerioL, Abt. I, 34, 737. 1903. 



