518 BIOLOGY OF PNEUMOCOCCUS 



constitutes a disadvantage in its use. A precaution to be observed 

 in this class of substances is to keep the compound from coming in 

 contact with free hydrochloric acid in the stomach. 



ADJUVANT ACTION OF CINCHONA COMPOUNDS WITH SPECIFIC 

 SERUM 



The first report on the combined action of optochin and im- 

 mune serum on pneumococci was that of Neufeld and Engwer 982 in 

 1912 and of Engwer 365 in 1913, who found in guinea pigs an aug- 

 mented action of the two agents when employed together. Another 

 observation reported by Boehncke 132 in 1913 suggested that opto- 

 chin may exert an auxiliary or possibly a synergistic action when 

 administered along with specific immune serum. In tests on white 

 mice, Boehncke 133 claimed better curative effects with a mixture of 

 ethylhydrocupreine and immune serum than with either agent 

 alone and that this favorable therapeutic action could be produced 

 by the combined use of both agents in less than the curative dose of 

 either. The observation was confirmed by Moore, 909 who concluded 

 that a single small dose of optochin base, which by itself exerted no 

 protective action against pneumococcal infection in mice, was ca- 

 pable of increasing by at least fifty times the threshold value of 

 antipneumococcic serum. The effect occurred only when the serum 

 and the infecting organism were of the same serological type and 

 proportionally was many times greater than a simple summation 

 of the protective action of the two single components of the mix- 

 ture. 



The phenomenon finds an analogy in the adjuvant action of so- 

 dium oleate with immune serum already quoted from Lamar 775 and 

 that of gold as reported by Gelarie and Sabin. 510 The use of cin- 

 chona derivatives, especially ethylhydrocupreine, in combination 

 with specific serum therapy would appear to possess the advantage 

 of making it possible to reduce the dose of the drug well below the 

 toxic limit as well as to enhance the curative action of the immune 



