852 



15. EFFECTS OF VARIOUS FACTORS ON INHIBITION 



that the antagonism of the ethanol inhibition by high pressure is reduced 

 or abolished at higher temperatures. 



Examination of a series of carbamates showed that only the lower mem- 

 bers of the series are made more ineffective inhibitors by high pressures, 



2000 

 PRESSURE 



Fig. 15-25. Effects of pressure on several inhibitions 

 of luminescence in P. phosphoreum. A, ethyl ether 

 (140 mM); B. procaine (6.4 mM); C, ethanol (500 

 mM); D, phenylcarbamate (4 rail); E, ethylcarba- 

 mate (780 mM); F, chloroform (50 mM); G, chloral 

 hydrate (16 mM); H, barbital; I, sulfanilamide (3.8 

 mM); and J, /j-aminobenzoate (10 m3I). (From 

 Johnson et al., 1942 a.) 



the inhibitions by the hexyl and octyl carbamates actually increasing with 

 rise in the pressure (Johnson et al., 1951) (Fig. 15-27). The inhibition 

 by methyl carbamate is characterized by a volume increase of around GO- 

 TO ml/mole up to pressures of 3000 psi,* but at higher pressures the cal- 

 culated volume increase becomes much greater (between 279 and 438 ml/ 

 mole). These values are remarkably large and it was suggested were partly 



One atm = 14.696 pounds/inch- (psi) = 1.0.33 kg/cm- (bars) 



