.1 .s r .1/ 1/ r/rinc asal vms 



105 



crease in toxicity and the concentration, and ( .'5) tlie same 

 temperature characteristics for the two isomers, have 

 been ol)served by Gaiise and Smarag'dova (ll)o8, ]9o9) 

 with nicotine on vertebrates (natural == laevorotatory), 

 with tartaric acid on fishes (natural = dextrorotatory), 

 and with cinchonine on ])aramecia (natural = laevoro- 

 tatory. Figure 13 shows that the dynamics of toxic action 

 are identical for dextrorotatory and for laevorotatory tar- 

 taric acids on the brood of the fish Lehistes reticulatus. 

 The temperature characteristics of toxic action for dex- 

 trorotatory tartaric acid was found to be 10,200 (cf. 



02 04 06 08 10 12 



Log. of effective concentration i.v-ii) 



Fig. 13. Killing action of the optical isomers of tartaric acid on the 

 fish Lehifites reticulatus. The lower graph represents the toxicity 

 curves in logarithmic coordinates. (From Gause and Smaragdova, 

 1938.) 



