THE GENUS STREPTOCOCCUS 143 



been recognized. Staphylococcus mastitidis character- 

 ized by whitish growth, acid production, and liquefying 

 power, is evidently a form of the genus Albococcus prob- 

 ably Alb. pyo genes. The various species of the genus 

 " Galactococcus" of Guillebeau are only well-recognized 

 forms of the genera Aurococcus, Albococcus, and Micro- 

 coccus. 



Staeheli (1904) has recently pointed out the great 

 variability exhibited by the streptococci associated with 

 diseases of the cow's udder (Str. agalactm contagiosce) and 

 their close relation to Str. pyogenes. Baruchello (1905) 

 was unable to distinguish the streptococcus normally 

 found in the intestine of the horse from Str. pyogenes ; 

 and to go still farther afield, recent observers attribute a 

 common silkworm disease to a form differing only in its 

 failure to coagulate milk (Sartirana and Paccarano, 1905). 

 The latter is perhaps the Micrococcus bombycis of Pas- 

 teur (Cohn, 1875). 



A third class of workers, the dairy bacteriologists, 

 approaching the subject from another standpoint, have 

 isolated the same group of organisms. The streptococcus 

 which is now clearly recognized as one of the commonest 

 "lactic acid organisms" in milk, and which was described 

 by Kruse (1903) as Streptococcus lacticus, shows no valid 

 specific differences from Str. pyogenes. Rolling (1905) 

 studied a number of races of streptococci obtained from 

 sour milk and concluded, in spite of slight differences in 

 acid production and other characters, that all were of the 



