MICHIGAN ACADEMY OF SCIENCE. 
133 
tively inert and the ion the reverse, the importance of knowing the 
extent of ionization becomes obvious. But in this problem we deal not 
with the single salt, but with a combination, and the effect of t his com- 
bination on restraining or bringing about ionization must be considered. 
Here also the concentration of each is fundamental. There is a great 
opportunity for a review of the work of antagonism in the light of 
ionization and in the light of the effect of combinations on this ioniza- 
tion. 
Not to be omitted here is the relation of adsorption phenomena, and 
whether we should include this discussion here or under a later head, is 
a question. We know that adsorption phenomena are well marked be- 
tween colloids and various other classes of compounds. Moreover, we 
know from the work of Hither R . 15 that tbe effect of a combination 
of substances is very great on the relative adsorption, one substance as 
it were crowding the other away and even crowding it away excessively. 
What role this plays in antitoxic action is as yet in the “suggestion” 
stage. Surely, however, its role is more important in such an experi- 
ment as the one just detailed, than in those where greater concentra- 
tions are employed. Again, in the problem of reactions in the solutions 
and the effects of combined influences we have to deal with molecular 
complexes, the significance of which we are only beginning to observe, 
by thermometer and by spectroscope. What relation one substance has 
in its inhibition role upon another must be carefully considered. 
Secondly, the effect may come about through changes in the plasma 
membrane. It is obvious that these changes must ultimatelv modifv the 
permeability of the limiting layer. In accounting for the phenomenon 
of antagonism, Loeb 16 has postulated the “tanning” theory and has shown 
in certain cases that antagonism depends upon a common cooperative 
action of both salts through which action the membrance becomes com- 
pletely or comparatively impermeable to both salts. He further con- 
cludes that each salt in solution by itself is toxic in view of the fact 
that it diffuses rapidly and comes into direct contact with the protoplasm 
of the germ. The change in the membrane which results in a modifica- 
tion of its permeability is explained by him as a process of coagula- 
tion through the action of the electrolytes in the protein colloids. This 
finds substantiation in the field of pure physical chemistry for col- 
loidals are coagulated by electrolytes if the electrolytes are strongly dis- 
sociated into ions and are present in sufficient quantity. 
It is also a possibility that the antagonistic action comes about 
through the effects of tlie solutions on the lipoids. The various schools 
are divided as to the distribution of the lipoids in the surface layer. 
This brings about a lack of uniformity, in the theories presented, as to 
the role of lipoids. Necessarily, the application of this theory of Over- 
ton has been most elaborate in the study of narcotics and anaesthetics 
since the Overton theory deals primarily with the class of substances 
used in anaesthesia. The theories concerning the effect of a combination 
of solutions on the lipoids conceived this effect to be more than a 
mere solvent action and postulate either an increase in the colloidal 
dispersion or else a 
parts of the plasma membrane. 
direct change of the relation of the constituent 
18 Physik. Chemie der Zelle u. Gewebe. 3. Aufl, p 278. 
,6 Biochem. Ztschr. Bd. 36. 275. 
