INFECTIOUS DISEASES. 75 



modification insoluble: 1-Tartaric acid; d-Methoxylsuccinic acid; 

 d-Mandelic acid. Penicillium glaucum destroys: d-Tartaric acid; 

 1-iEthoxysuccinic acid; 1-Mandelic acid. Lewkowitch's schizomycetes 

 destroy: 1-Tartaric acid; d-Mandelic acid. Strychnine separates: 

 1-Lactic acid; 1-^Ethoxysuccinic acid. Many other examples can be 

 cited, the principal difference being that the alkaloids separate the 

 insoluble optical isomer and the micro-organisms make use of one of the 

 optical isomers to build up their own structure. 



The bi-partic powers of the alkaloids are as limited as those of the 

 micro-organisms; thus strychnine can bi-part lactic acid, cinchonine 

 malic but not lactic acid, etc., and most likely two acids bi-parted by 

 the same base have analogous configuration. 



From these arguments, I take it that predisposition and immunity 

 are intimately connected with stereo-chemical changes, i. e., where the 

 configuration, according to Fischer, of the nutrient, on the one hand, 

 and the ferments, enzymes, sporozoa, etc., on the other, must be to each 

 other as lock and key. Moreover, I believe that infectious diseases are 

 not caused by any one class of ferments, but by many acting syner- 

 getically. In line with these results it strikes me that predisposition is 

 a condition well suited to act synergetically when the missing ferment 

 presents itself. Immunity, on the other hand, betokens the absence of 

 a number of active synergetic ferments, owing to lack of requisite 

 configurations. 



While this suggestion may seem to offer one hazy hypothesis for 

 another equally hazy, it opens a broader field for investigation, it admits 

 of better explanations of observed results, and it agrees with our ideas 

 that the demolition of complex organic materials, such as blood and 

 the tissues, takes place step-like and not abruptly. 



Surely some day physiological chemistry will be sufficiently powerful 

 to shed its light through the mist now surrounding the so-called vital 

 processes — clearly define the differences between the healthy and the 

 disease-disturbed systems — teach us how to preserve the former and 

 counteract the latter, by other than merely empirical methods. 



When that day comes, infectious diseases like tuberculosis will no 

 longer rob the stricken patient of all hope and cause him to be a 

 constant menace, dreaded even by those who love him most dearly. 

 When that day comes, parents no longer need be haunted by the fear 

 that predisposition be transmitted to their children born and unborn. 



