^^rih'AL T\\ IHT AND OPT. ACTIVITY 89 



better on iiahiral d-arginiiie than on the racemic dl-ar- 

 giuine. Therefore, the dextrally and the sinistrally twist- 

 ed organisms are alike in the optical properties of their 

 basic protoplasmic constituents, since nutritive sub- 

 stances of the natural configuration are more favorable 

 for both of them. 



d. E e s p i r a t i o n. The oxidation of glucose by the 

 dextral and sinistral strains of Bacillus mycoides was 

 determined by the Warburg technique at three tempera- 

 tures : 22°, 25° and 28°C. As is characteristic of biolog- 

 ical processes generally, the velocity of respiration rose 

 exponentially with the rise of temperature, and practi- 

 cally at the same rate in the sinistral and in the dextral 

 strains of the bacillus. Consequently the phenomenon of 

 heat injury, which was characteristic of the growth of 

 the dextral strain, was not observed in respiration on 

 glucose. 



The general conclusions to draw from these investiga- 

 tions is that the inverse, dextral strains of Bacillus my- 

 coides are weaker than the typical, sinistral ones. This 

 was observed in the rate of growth at 24° to 28° and in 

 the deficiency of an enzymatic action. 



5. Some Physiological Properties of the Dextral and of 

 the Sinistral Strains of the Snail, Fniticicola lantzi. 

 Anabolic gain, I'esistance to starva- 

 tion, mortality rate. The results of the in- 

 vestigations on Bacillus mycoides are paralleled by the 

 data obtained with Fruticicola lantzi. 



Gause and Smaragdova (1940) made a comparative 

 study, under well controlled laboratory conditions, of the 

 physiological behavior of the dextral and sinistral indi- 

 viduals of this snail. They investigated (1) the velocity 

 of anabolic assimilation as judged by the change in weight 

 w^hen the snails were fed for a long time on carrots; (2) 

 the velocity of the catabolic loss as determined by the 

 decrease in weight when the animals were kept in a moist 

 chamber without food; (3) the mortality rate in the sec- 

 ond group of experiments. 



