68 BIOLOGY OF PNEUMOCOCCUS 



There appeared to be marked and characteristic divergences in the 

 behavior of different types of pneumococci toward this sugar, the 

 variant RIII being first and SI second in order of glycolytic ac- 

 tivity. It was Hewitt's belief that inorganic phosphorus played an 

 essential part in the fermentation of glucose and that this part 

 was independent of its buffering action. The full benefit to Pneu- 

 mocQecus from phosphates was only obtained when media contain- 

 ing these salts were sterilized by filtration and not by autoclaving. 



The cleavage of maltose and lactose, unlike that of glucose, is 

 due respectively to a maltase and a lactase in the pneumococcal 

 cell (Fleming and Neill 402 ), while Neill and Avery 954 have demon- 

 strated a raffinase. 



A significant and distinctive enzymatic property of Pneumococ- 

 cus is its ability to ferment inulin, a polyose from dahlia bulbs. It 

 was Hiss 649 who first in 1902 discovered that, by means of this 

 property, it was possible to differentiate pneumococci from the 

 closely related members of the tribe Streptococcaceae. Serum- 

 water containing one per cent inulin supported growth of Pneumo- 

 coccus, resulting in the development of acidity and coagulation, 

 while streptococci, although growing, failed to form appreciable 

 acid or to coagulate the medium. It was the use of this method 

 which, with other biological characters, indicated that the so-called 

 Streptococcus mucosus was in reality a pneumococcus. 



Duval and Lewis 342 overcame the variations encountered in va- 

 rious batches of serum-water by using inulin broth. They found 

 that in its fermentative ability Streptococcus mucosus closely re- 

 sembled Pneumococcus, but decided that the inability to ferment 

 inulin did not necessarily exclude an organism from the species, 

 since some pneumococci failed to show this character. Dochez and 

 Gillespie 822 described a strain of Pneumococcus mucosus that did 

 not ferment inulin. Berry 106 also observed the pneumococcal char- 

 acters of S. mucosus, and her results agreed with those of Duval 

 and Lewis in that she encountered other strains of pneumococci 

 that failed to attack inulin, as well as variations in this respect 



