136 PHYSICAL CHEMISTRY 



many hours. This charcoal was heated to redness and cooled 

 in a C0 2 -free atmosphere. The charcoal adsorbed all of the C0 2 

 produced for a time, but after it had become saturated with this 

 gas, the volume of 2 used up was half the volume of the C0 2 

 given out. No food substance was found that could be burned 

 in this way. Rona and Tosh (1914) found, however, that ure- 

 thane displaces adsorbed dextrose from animal charcoal. 



Meyerhof (1914 b) observed that the catalysis of hydrogen 

 peroxide by colloidal platinum may be inhibited by anesthetics. 

 Since the anesthetic did not reduce the number of particles of 

 platinum seen in the ultramicroscope he concluded that the an- 

 esthetic displaced the H 2 2 from the surface of the platinum. 



Meyerhof .(i9' I 5) showed that solution of invertase from yeast 

 may be inhibited by anesthetics. The following table shows the 

 concentration of anesthetic that reduced the inversion of 3 per 

 cent cane sugar solution 30 per cent: 



Methyl alcohol 3 mol 



Ethyl " 1.3 " 



Propyl " .5 " 



Isobutyl " .27 " 



Isoamyl (fermentation) .21 " 



Methyl urethane .95 " 



Ethyl " .97 " 



Propyl " .48 " 



In this case the Tyndall phenomenon was increased, but this 

 may have been due to an increase in the dispersion of light by 

 particles, due to their rhclosure in films of anesthetic, rather than 

 an increase in the size of the particles. In harmony with the 

 view that the reduction in activity of the enzyme is due to the 

 displacement, by the anesthetic, of the sugar from its surface, 

 is the fact that if the concentration of the anesthetic is varied 

 its effectiveness follows the typical adsorption curve (Fig. 24). 

 The concentration of anesthetic necessary to anesthetize tadpoles 

 reduced the inversion about 20 per cent, but this reduction was 

 increased by dilution of the sugar solution. 



If the anesthetics are added in greater concentrations to 

 enzyme-containing extracts of cells, precipitation may occur. 

 The enzymes are carried down in the precipitates, but it is not 



