514 BIOLOGY OF PNEUMOCOCCUS 



tween therapeutic dose and toxic dose was narrower than in the 

 case of the other derivatives studied, appeared to be less injurious 

 to the natural defenses of the body. 



EFFECT ON VARIOUS PNEUMOCOCCAL TYPES 



Felton and Dougherty noted variability in the bactericidal ac- 

 tion in vivo of the compounds on different strains of pneumococci, 

 since the virulence of the culture contributed to fluctuations in the 

 effect of the drug. The observation was contrary to those of 

 Kleinschmidt, 722 of Moore, and also of Solis-Cohen, Kolmer, and 

 Heist, whose results indicated that the germicidal power of the 

 cinchona derivatives which they studied, possibly with the excep- 

 tion of some Type III strains, was apparently the same for all the 

 types of pneumococci tested. Schiemann, and Schiemann and Ishi- 

 wara, however, had earlier reported that virulent strains were 

 more susceptible to the effect of optochin than were attenuated 

 strains, and that the source of the culture was also concerned in 

 sensitivity to drug action. 



According to Wright, Morgan, Colebrook, and Dodgson, and to 

 Schiemann and Ishiwara, optochin, unlike some metallic salts, loses 

 little of its germicidal power in the presence respectively of human 

 serum or rabbit serum, but Solis-Cohen and his associates re- 

 ported that the agent lost from one-fiftieth to one-tenth of its ac- 

 tivity in a menstruum of serum as compared with that exhibited in 

 isotonic salt solution. 



Wright and his co-workers had early found (1912) that three 

 hours subsequent to the administration of optochin to adults the 

 serum of the treated subjects would kill pneumococci in vitro. 

 Moore and Chesny 910 later made the same observation but stated 

 that the effect depended upon the administration of a sufficient 

 amount of the drug and the spacing of the doses. Similarly, Bald- 

 win and Rhoades 69 concluded that the ethylhydrocupreine base, as 

 employed by them, is absorbed from the gastro-intestinal tract in 



