ASYMMETh'W ANALYSIS 113 



The observed lethal action, which is the resultant of the 

 partial lethal action of hydroo^en ions and of that of non- 

 dissociated molecules, would then decrease first and in- 

 crease afterwards as we indicated. Other investigations 

 on the mode of action of organic acids have been sum- 

 marized by Lepeschkin (1937). 



Since optical isomers have all their physical and chem- 

 ical properties identical, except those which are directly 

 related to their structural configuration, one will observe 

 that, if the common properties only are involved in the 

 killing mechanism, the two isomers should produce the 

 same effect, while, if the properties which are ditferent 

 in the two isomers are involved in the killing action, the 

 two isomers will produce a different effect. It is further- 

 more assumed that the properties which are specific to 

 each isomer will be involved in the interaction of these 

 isomers with the protoplasm itself, within the cell, in op- 

 tically active medium, while the properties common to 

 the two isomers, such as the electric charge, the electric 

 conductivity (observed by Ostwald, 1889, to be the same 

 in the isomers of tartaric acid), the osmotic pressure, 

 etc., will be involved in such processes as conduction to- 

 ward the protoplasmic matter itself. Consequently, if 

 our assumptions are correct, when solutions of dextroro- 

 tatory and of laevorotatory acids are equally toxic for a 

 given animal, one may infer that the killing results from 

 physico-chemical injuries concerned with conduction or 

 the like. If, on the other hand, the two optical isomers 

 are not equally toxic, it is natural to think that the sur- 

 face effects just described could not induce death, so that 

 non-dissociated molecules have time to penetrate inside 

 the cells and there carry out their stereo-specific destruc- 

 tive actions. 



With these ideas in mind, Gause and Smaragdova 

 (1938) determined the coefficient of relative toxicity of 

 the optical isomers of tartaric acid on various fresh water 

 animals. Some of their results are given in Table 18. 



