62 BIOLOGY OF PNEUMOCOCCUS 



of Lord and Nye, 835 " 7 who found that more rapid dissolution of 

 pneumococci occurred in bile than in standard buffer solutions and 

 that lysis proceeded at a more rapid rate when the reaction of the 

 mixture was slightly alkaline. The authors attributed the effect to 

 the more rapid death of the organisms in bile and, hence, to the 

 liberation of a larger amount of enzyme at the optimal hydrogen 

 ion concentration. 



Whatever may be the facts regarding the exact nature of bile 

 solution of Pneumococcus, it cannot be gainsaid that this phe- 

 nomenon and that of autolysis bear striking similarities. Whether 

 or not they are due to entirely separate mechanisms, bile may be 

 regarded as an accelerator of natural autolysis. 



Sensitiveness to Germicides and Other Chemical Substances 

 Pneumococcus is highly vulnerable to the usual antiseptics and 

 germicides. The problem of killing pneumococci and of rendering 

 infectious material harmless is a simple one, and can be dismissed 

 with scant discussion. As an example of the effective concentra- 

 tions of two common germicides, Schiemann and Ishiwara 1230 gave 

 for the growth-inhibiting strength of phenol and mercuric chloride 

 1 to 600 and 1 to 100,000, respectively. These figures were ob- 

 tained by adding a small quantity of a twenty-four-hour broth 

 culture of pneumococci to 5 per cent ox-serum containing varying 

 dilutions of the two substances.* 



Simon and Wood 1288 " 9 investigated the action of a large number of 

 dyes and concluded that the majority of the basic type, especially 

 those of the triphenylmethane series, in a concentration of 1 : 100,000 in 

 agar were inhibitory for pneumococci as tested by making a stroke cul- 

 ture on the medium. Acriflavine (trypaflavine) acts powerfully both on 

 virulent and non-virulent pneumococci (Schiemann and Baumgarten, 

 1923). Norton and Davis (1923) found that organisms belonging to the 

 S. viridans and Pneumococcus groups were inhibited by dyes to the 

 same extent, so that none could be used for the purpose of differentiat- 

 ing between them. 



* Quoted from Browning.i 5 ^ 



