520 BIOLOGY OF PNEUMOCOCCUS 



the chemical. Drug-fastness was retained for some time during 

 cultivation in optochin-free media as well as during animal pas- 

 sage. Lewy noted that during the treatment just described vari- 

 ants of the original strain appeared (Modification B) which 

 lacked sensitivity to optochin. The resistance or tolerance was 

 general in nature and was not to be confused with specific opto- 

 chin-fastness. In an analysis of the specificity of optochin-fastness 

 in pneumococci, Lewy 808 found that there was a slight, specific ac- 

 tion of quinine as well as of hydroquinine. With more marked 

 chemical variations in the side-chain, as in the case of the higher 

 homologues, or in the nucleus of the optochin molecule, the spe- 

 cific action of optochin on Pneumococcus disappears. The sus- 

 ceptibility of the optochin-fast strain to other compounds quite 

 foreign to this class of substances suggested to Lewy the presence 

 of other sensitive groups — chemoceptors — in the pneumococcal 

 cell. 



Heightened susceptibility. That the reverse of acquired toler- 

 ance by Pneumococcus may take place was shown by the experi- 

 ments of Schnabel 1241 and of Schnabel and Kasarnowsky. 1242 Cul- 

 tures of pneumococci injected into mice with subsequent adminis- 

 tration to the infected animals of dilute optochin solutions caused 

 the organisms after a twenty-four-hour sojourn in the body of the 

 treated animals to develop a heightened susceptibility to the drug. 

 In addition to the influence of lesser concentrations of optochin, 

 the length of exposure of the organisms in the treated animals was 

 a factor in increasing the sensitivity of the cocci. 



Summary 



In reviewing the data which have been accumulated from experi- 

 ments in the test tube and in the animal body, the conviction is 

 gained that not yet has the ideal drug been found that lends itself 

 to the chemotherapy of pneumococcal infection. The action of cin- 

 chona derivatives in affecting the vital characters of Pneumococ- 



