114 ASYMMETRIC ANALYSIS 



TABLE 18 



Coefficients of Relative Toxicity of Dextbokotatory Tartaric Acid 



AND Significance of Differences in Relative Toxicity in 



Different Groups of Animals. 



(From Gause and Smaragdova, 1938.) 



(M is the coefficient of toxicity; P.E. is the probable error.) 



(1) Protozoa 



M±P.E. 0.981±0.019 



(2) Worms (3) Crustacea (4) Pisces 



1.048±0.010 



1.064±0.010 1.305±0.011 



The figures represent the mean vahie (M) of the data for 

 all the animals of a given phylmn. The probable error 

 (P.E.) from the mean is also given. 



The coefficient of relative toxicity in Protozoa is close 

 to unity, which means that the dextrorotatory and laevo- 

 rotatory tartaric acids are equally effective. On the con- 

 trary, in fishes, the optical isomers of tartaric acid dif- 

 fer strongly in their killing power, the stereo coef- 

 ficient being 1.305. The other groups of invertebrates 

 investigated occupy an intermediate position between the 

 protozoa and the fishes in their differential sensitivity to 

 the two isomers, the coefficient of relative toxicity reach- 

 ing 1.0-1-8 in the worms and 1.064 in the Crustacea. 



Similar results were obtained also with the optical 

 isomers of malic acid. 



According to the assumptions made, these data would 

 show that, in the killing of lower animals by tartaric 

 and malic acids, there predominates some electro-chem- 

 ical surface injury, while in higher animals internal chem- 

 ical injuries caused by non-dissociated molecules would 

 occur. 



Cushny (1903, 1926) called into question the obser- 

 vations on the differences in the killing power of the dex- 

 trorotatory and the laevorotatory isomers of tartaric acid 

 in vertebrates, because the weak specific action of tar- 

 taric acids might, according to his opinion, be totally 

 concealed by the more powerful effect of the hydrogen ion 



