SCIENTIFIC PROCEEDINGS. 



Abstracts of the Communications. 



Forty seventh meeting. 



The Laboratory of Natural History, College of the City of New York. 

 February 21, IQ12. President Morgan in the chair. 



24 (633) 



The fermentation of carbohydrates and other organic media 



by streptococci. 

 By 0. E. A. WINSLOW. 



[From the Department of Public Health, American Museum of 

 Natural History, New York.] 



The study of the fermentative powers of the streptococci has 

 been carried out in England by merely noting the change of 

 color in litmus media. In this country, Palmer and the writer, 

 Broadhurst and Hilliard have used the more exact methods of 

 titrating inoculated tubes and uninoculated controls, using 

 phenolphthalein as an indicator and plotting the quantitative 

 results obtained. The line of demarcation between fermenting 

 and non-fermenting forms is drawn at the intermodal point 

 between the peaks of the curve. A comparison of several hun- 

 dred results obtained by English and American methods shows 

 that the English method gives a uniformly higher proportion 

 of fermenters, suggesting that a number of strains producing a 

 very slight amount of acid and properly classed as non-fermenters, 

 are recorded as positive by the English method. 



A study of the correlations between action on different organic 

 media shows that those substances tested may be arranged in a 

 definite order of availability, such that a positive reaction in one 

 medium usually implies that all those earlier in the series will be 

 fermented, while failure to act on a given substance almost always 

 implies that substances later in the series will not be fermented 

 either. Among the streptococci dextrose comes first in order of 

 availability, then the disaccharides, lactose and saccharose, and 

 the glucoside, salicin (which easily yields a simple sugar). The 



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