ASYMMETRIC ANALYSIS 115 



concentration which is known to be identical in tlie solu- 

 tions of both optic isomers. But the objections of Cushny 

 must be considered in the light of the following recent 

 observations : 1. It is at present doubtful that the ef- 

 fect of hydrogen ions is always dominant over the spe- 

 cific action of non-dissociated molecules of organic acids 

 (cf. Gause, 1936), 2. Furthermore, Sizer (1937), in a 

 work on the stimulative effect of organic acids on various 

 animals has shown that Balanus halanoides is more sus- 

 ceptible to the action of hydrogen ions, while in Fimdulus 

 heteroclitus the effect of these ions does not predom- 

 inate over the specific action of nondissociated mole- 

 cules. 



There is another essential point in the investigations 

 of Gause and Smaragdova. If the animals studied are 

 arranged in the order of increasing difference in the 

 toxic jDOwer of the two optical isomers : Protozoa 

 < Worms < Crustacea < Pisces, one obtains the phylo- 

 genetic series of gradually increasing differentiation. 

 This is not surprising if one considers the fact of the 

 progressively diminishing relative vital importance of 

 the physico-chemical injury of integuments when one 

 ascends the animal series. The nature of susceptible 

 integuments, the injury of which, according to our as- 

 sumptions, brings about death in lower animals, is not 

 known. It is possible that the respiratory surfaces are 

 among the most susceptible. In Protozoa the whole sur- 

 face of the cell is the respiratory surface. When one 

 ascends the animal series, respiratory surfaces become 

 more localized and more differentiated and the physico- 

 chemical injury of these surfaces progressively dimin- 

 ishes in magnitude as a cause of death. The results of fur- 

 ther investigations along this line have recently been pub- 

 lished by Gause and Smaragdova (1939). 



