1918] 
BONNS—ETHERIZATION AND ENZYME ACTIVITY 255 
Saccharomyces cerevisiae. Coagulation temperature limits 
of the membranes were noted and compared with those of 
proteins. A determination of albumin coagulation concen- 
trations for lipoid solvents, as ether, chloroform, etc., showed 
that they were much greater than those acting on the plasma 
membrane. The concentrations appeared to correlate with 
the partition coefficients in water and oil. The general con- 
clusion was reached that proteins or loose protein combina- 
tions are important constituents of the plasma membrane, and 
that bodies of a lipoid nature are also present; whether the 
latter are lecithin or cholesterin compounds, as Overton has 
suggested, or merely fat bodies, was not concluded. Data 
harmonizing with the Overton hypothesis have been pub- 
lished by Zehl (708), who studied the action of varying tem- 
peratures in relation to the toxic action of a diversity of 
poisons upon two fungi. The noteworthy results with respect 
to the present discussion were the marked reductions in 
toxicity of the common anaesthetics for both Aspergillus and 
Penicillium with rise in temperature, the limiting toxic concen- 
trations of both chloroform and ether being notably increased. 
Such action, Zehl has pointed out, accords with reduction of 
the partition coefficients and threshold concentrations of nar- 
coties with increase of temperature, as shown by Overton. 
Choquard (713), from a study of muscular response of 
tissues with scant and abundant lipoid content to treatment 
with narcotics, found the Overton theory insufficient explana- 
tion for the results obtained. Rapidity of narcotic penetra- 
tion appeared to be an important factor involved. Another 
type of experimental data is that of Alexander and Cserna 
(13) who studied the gas exchange of the brain in ether 
narcosis as compared with the nareosis produced by non-lipoid 
solvents. The values of the carbon dioxide production and 
oxygen evolution associated with the respective kind of an- 
aesthesia are the grounds on which these workers take ex- 
ception to the Overton theory as an explanation. They in- 
cline to a view more in harmony with that of Mansfeld (’09). 
Osterhout (2132) also opposes the Overton view with the 
results of his experiments on plasmolysis of Spirogyra with 
