VIT^UIINES AND GROWTH OF STREPTOCOCCUS 



451 



The flasks containing each of (he three media described were 

 inoculated with a twenty-four hour culture of the streptococcus 

 and incubated at 37°C. Examinations for growth were made 

 after seventeen, twenty-four and forty-eight hours. Assuming 

 that the water-soluble B can be extracted by hot 95 per cent 

 alcohol, the medium made up with the alcohol extract should 



TABLE 1 

 Growth of a streptococcus in various media 



95 per cent alcoholic yeast ex- 

 tract -H peptone 



Extract from yeast residue -1- 

 peptone 



Extract of regular yeast -f 

 peptone 



Fraction I + peptone 



Fraction II + peptone 



Filtrate A -f- peptone 



Yeast extract treated with 

 Lloyd's Reagent + peptone 



Regular j'east extract + pep- 

 tone 



REMARKS 



Should contain water-soluble B 



Should not contain water-solu- 

 ble B 



Contains water-soluble B 



Should contain some water-solu- 

 ble B 



Should contain most water-solu- 

 ble B 



Should contain little if any water- 

 soluble B 



Should not contain water-soluble 

 B from yeast 



Should contain water-soluble B 

 from yeast 



* Slight. 



contain this vitamine. The medium prepared from the alcohol- 

 extracted yeast should not contain the water-soluble B, or at 

 least the amount should be greatly reduced. Further, the me- 

 dium made from the regular yeast should of course contain the 

 vitamine. 



The results shown in table 1 were of considerable interest to 

 us. The growth was recorded by -f signs which were increased 



