526 REPORT—1904. 
determines the velocity of the osmosis. He assumes that in the first instance a 
dissolution takes place in the fatty substance of the membrane at a velocity pro- 
portional to this coefficient, and that thereupon the substance passes on from the 
membrane to the interior of the cell. Moreover, Overton, and independently 
Hans Meyer, point out that all the reliable narcotics, anaesthetics, and antipyretics 
belong to the class of rapidly diffusing substances, and hence they deduce the 
theory that the efficacy of a narcotic depends principally on its lipoid solubility. 
These theories, however, in so far as they concern osmotic velocity, are erroneous, 
The author's investigations on the constants of capillarity of substances, especially 
solutions, have led to the result that the greater the osmotic velocity of a substance 
soluble in water, the more this substance reduces the constant of capillarity of 
water, whilst substances which cannot penetrate membranes (with regard to which 
the membranes are semipermeable) raise this constant. Among hundreds of com- 
pounds examined plasmolytically by Overton, and asto capillarity by the author, 
there is not one case in which capillary and osmotic phenomena do not correspond. 
It is evident that osmotic velocity and surface tension run parallel. Hence the 
difference of the surface tensions—or of the internal pressures—is the motive force 
in osmotic phenomena ; it is to this difference that osmotic pressure is due. 
The theory here stated leads to a new conception of the phenomena of diffusion 
and solution. Suppose that an aqueous solution of a salt is brought into contact 
with pure water. According to the prevalent theory the salt particles or the ions, 
in virtue of their ‘ osmotic pressure,’ migrate into the pure solvent, but according 
to the author’s view it is the pure solvent which, in virtue of its low surface ten- 
sion, migrates into the salt solution. Again, let two liquids capable of dissolving 
in each other be brought in contact, or let a solid be in contact with a pure sol- 
vent, then the solution tension will depend chiefly on the difference between the 
surface tensions. Irom this we may expect that when a liquid or solid substance 
dissolves in a solvent the surface tension of the solution will never fall below that 
of the dissolving substance, and if the surface tensions of solution and dissolving 
substance be equa), the solution will be saturated. The surface tension of a saturated 
solution is i maximo as low as that of the dissolved substance, consequently the 
latter value determines the shape of the curve of the surface tension of solutions. 
From the author’s former investigations he deduced the law that equal equiva- 
lents of substances belonging to homologous series, which exercise a strong influ- 
ence on capillarity (ordinary alcohols, fatty acids, esters, &c.), lower the capillary 
height of water in the proportion 1:3:37:3° . . . If three mols. of methyl alcohol 
reduce the surface tension of water as much as one mol. of ethyl alcohol, the con- 
clusion is justified that the tendency to increase the surface tension of water is 
three times less in the case of methyl alcohol than in the case of its nearest homo- 
logue. Hence the tendency of methyl alcohol to separate from the solution may be 
considered as three times less than the corresponding tendency of ethyl alcohol, 
or, in other words, the solution tension of substances belonging to homologous 
series, which exercise a strong influence on capillarity, increases with increasing 
molecular weight in the proportion 1:3:3?: 3°... Ifa layer of a liquid insoluble 
in water, say benzene, he placed upon an aqueous solution of different alcohols, 
esters, &c., the amount of dissolved substance of which this liquid will deprive the 
water will be greater in exact proportion as the solution tension is less, Dis- 
tribution coefficients and solution tension—and hence also surface tension and 
osmotic velocity—are therefore proportional magnitudes in first approximation. 
Thus Overton’s theory is erroneous in as far as it represents penetration into 
the cell as depending on the degree of lipoid solubility, for dissolution of the dis- 
solved substance in the lipoids certainly does not take place. The motive force is 
the surface tension. Overton and Meyer have pointed cut that the efficacious 
narcotics, anaesthetics, and antipyretics all belong to those compounds which pene- 
trate their membranes rapidly, Rapid penetration into the cell seems to be the 
most essential condition for enabling a narcotic to exercise its effect on the interior 
of certain cells. Thus narcotics which differ materially in their chemical compo- 
sition may possibly exercise their action in different cells, and this action may 
vary considerably even when exerted on one and the same species of cell, But if 
