IVOR CORNMAN 



139 



affects cellular processes. One could resort to other means to justify the 

 ends. Suppose, for instance, that the molecule hydrolyses and reacts at 

 the carboxyl group, so the ester group is irrelevant. But the higher esters 

 are more potent narcotics and division-inhibitors than the lower esters. 

 Potency is increased by adding carbons at either end, at least up to ten 

 carbons (1). This point needs no elaboration, inasmuch as the carbamates 

 so neatly fit the pattern of non-specific hypnotics. Accordingly, this presen- 

 tation is based on the supposition that the molecule works as an intact unit, 

 and the argument will be developed that the simple carbamates act alike. 

 Temperature entered the picture as a result of comparison of responses 



Fig. 2. Arbacia cleavage time 

 in 55 mM urethan. First cleavage 

 retarded 6% at 20.6° and 20% 

 at 16.6°C. 



20.6*C 

 CONTROL 



O O 



URETHAN 



Zy — -.A 



MIN AFTER PERT 

 170 200 



^ 



I r 



of subtropical urchins such as Tripneiisfes and Lijtechinus with those of 

 Arbacia and the sand dollar, Echinarachnius. Temperature was a logical 

 point of difference, so we set up water baths at an intermediate temperature 

 that could be used at Woods Hole or Bermuda. These experiments were in 

 part a screening project, and it would be convenient to refer all data to a 

 common standard. Still the carbamates would not conform in different 

 species, even at identical temperatures. The relationship between tempera- 

 ture and concentration of several carbamates in the two northern species, 

 Arbacia and Echinarachnius, was subjected to more detailed analysis. 

 Three concentrations were run simultaneously at three temperatures 

 spaced at 4° intervals. The eggs were fertilized and at 10 minutes were 

 placed in the carbamate solutions. 



In figure 2 the effect of 4° differences in temperature is distinct in abso- 



