MICHIGAN ACADEMY OF SCIENCE. 
185 
the Overton theory, while giving’ the most extensive study of 
permeability yet deduced, was developed before the general ap- 
plication of physical chemistry. If, therefore, we hold to the 
belief that the plasma membrane is colloidal or part colloidal in its 
nature, we are not permitted to transfer facts of mere solubility in 
the realm of pure solutions, into this domain of colloidal chemistry. In 
the application of this ingenious theory, chemical facts dealing with 
another class of compounds are carried over to too great an extent to 
make this theory a safe one on which to build. 
As to the “tanning” theory of Loeb, one must l>e cautious. This is 
perhaps the most ingenious of all theories in permeability, but one 
which so far is not of universal application. Until the antitoxic action 
between a wide range of compounds can be given for colloids apart from 
the cell, we shall need to suspect other factors at work besides the mere 
coagulation of the cellular limiting membrane, or at least look upon 
such coagulation only as a result of some other process. 
Explanations based on the third class are as yet too general to enable 
us to advance far. For the special case under consideration, the hypo- 
thesis about to be advanced may properly fall in part under this head. 
In the case of the antitoxic action of chloral hydrate and copper sul- 
phate, the writer would like to call attention to the catalytic power of 
small amounts of copper. It is a well known fact through the work 
of Ostwald, Bigelow and others , 21 that a mere trace of Cu ions 
causes a rapid decomposition of NaHSO s and tlpit substances 
such as glycerine, mannite and a number of others inhibit strongly 
this catalytic action of copper. Experiments performed with a 
dilute solution of copper and a number of organic compounds 
which will be reported more fully later lead to the belief that chloral 
hydrate may affect the action of copper in some anti-catalytic way. Be 
this a mere “poisoning” in the solution, such as carbon monoxide or 
IvCN are known to exert upon catalyzers or not, the inhibition ex- 
hibited by the chloral hydrate must stand in some relation to the plant, 
either to the plasma membrane or to the cell. Experiments are in 
course of preparation in the attempt to answer some of these puzzling 
questions thus brought to light. It has been thought worth while to 
focus attention on this feasible but neglected possibility. 
In summarizing, the author has tried to give more than the mere 
record of an experiment, lie has reviewed very briefly the classic ex- 
periments on antagonism and has arranged these as it were into three 
groups, and has attempted to show that the experiment he performed 
dealt with different conditions from any brought forward so far. The 
relation of this problem to general physiology and to agriculture was 
mentioned. One typical curve from the experiments was chosen for 
this preliminary paper. Before developing a theory for the explanation 
of the results obtained, he has reviewed briefly some of the possible 
causes for antagonistic action. If is conceived that the results may 
come about, from effects within the solution itself, in the plasma mem- 
brane, or within the cell, or there may be combinations of these effects. 
Since the theories suggested were not entirely positive, another theory 
was advanced, namely, that in the particular case studied the action of 
21 Zeitschr. f. Physik. Chem. Bd. 26, 1898, p. 493. 
