156 



WINSLOW, ROTHBERG AND PARSONS 



with mannitol, raffinose, inulin and salicin (and perhaps with 

 glycerol and erythritol) which as our observations suggest were 

 probably erroneous. 



From our detailed quantitative studies with the new indicators 

 it seems evident that salicin, inulin, raffinose, dulcitol and man- 

 nitol are attacked by the staphylococci so rarely as to be of no 

 serious diagnostic value; that glucose, maltose and sucrose are 

 most readily attacked and with about equal frequency, and that 

 lactose is slightly, though distinctly, less available than glucose, 

 maltose and sucrose. It is of interest to note that the indicated 

 metabolic gradient is different from that which occurs in the 



TABLE 4 



Fermentation results reported by Dudgeon (1908) on basis of change in color of litmus 



colon group or among the streptococci. In both the latter 

 groups lactose is more readily attacked than sucrose and among 

 the colon bacilli, at least, sucrose and raffinose (the two ketonic 

 sugars) are fermented with equal frequency. Among the staph- 

 ylococci the fermentative processes involved must be distinctly 

 different since sucrose is more readily fermented than lactose while 

 raffinose is not attacked at all. 



The action of the staphylococci upon glucose, maltose, sucrose, 

 and lactose would seem to offer a possible basis for classification, 

 although the marked differences due to the effect of the medium 

 indicated in figure 1 would suggest that the use of this property 

 as a differential test might prove of doubtful value. 



