CHEMOTHERAPY 513 



concentrations of about one to one million and somewhat less in- 

 hibited the growth of pneumococci, while its bacteriostatic and 

 pneumococcidal action was exerted in solutions of high protein 

 content. The fact is of importance in relation to the effect of opto- 

 chin on pneumococci in the blood stream — an effect demonstrated 

 by Wright, Morgan, Colebrook, and Dodgson, as well as by Kol- 

 mer and Borrow. 742 The experiments of Moore 908 showed the highly 

 specific action of ethylhydrocupreine hydrochloride on pneumo- 

 cocci and, moreover, disclosed the fact that the phenomenon took 

 place with pneumococci of all the four groups tested. So specific 

 was the effect that Moore saw in it a means for the identification of 

 pneumococci. 



The preeminence of ethylhydrocupreine among the quinine de- 

 rivatives was established by Tugendreich and Russo, 1429 an obser- 

 vation confirmed by Solis-Cohen, Kolmer, and Heist 1304 among 

 others. Felton and Dougherty 422 made a comparative study of four 

 closely related synthetic cinchona derivatives. The first prepara- 

 tion was hydroquinine chloracetanilide, and the remaining three 

 were substitution products of the first compound. The effect of the 

 preparations was tested in vitro and in vivo against a young cul- 

 ture of Type I Pneumococcus. The in vitro tests were carried out 

 by holding the dose of the drug constant in mixtures with varying 

 amounts of culture, and then by injecting uniform amounts of the 

 organism and increasing doses of the drug. In the in vivo experi- 

 ments, a fatal dose of the culture was injected and the medicament 

 administered in the maximal tolerated dose. All four compounds 

 tested were found to display rapid pneumococcidal activity both in 

 the test tube and in the peritoneal cavity of mice and to a lesser 

 extent in rabbits. Optochin appeared to be the slowest in action, 

 but its action was not so easily inhibited either in vitro or in vivo. 

 The meta substitution product (hydroquinine ra-chloracetylamino- 

 phenol) exerted the strongest killing action on pneumococci when 

 injected simultaneously with the culture into the peritoneal cavity. 

 However, optochin, notwithstanding the fact that the zone be- 



