Osmosis, Solubihty, and Narcosis. 705 
theories, have very justly met with general notice and 
attention ; and indeed these theories shed light on a number 
of extremely important physiological, biological, pharmaco- 
logical, and medico-therapeutic problems, so that it is scarcely 
surprising that even certain weak points in the theory have 
been hitherto overlooked. 
And yet, interesting as are Overton’s experiments, and 
ingenious as his theories appear, they are nevertheless erro- 
neous in so far as they concern osmotic velocity, as I shall now 
proceed to prove. 
The weightiest objections to Overton’s theory are as 
follows * :— 
The fact that osmotic velocity goes parallel with lipoid- 
solubility is doubtless worthy of notice. But if—as Overton 
assumes—there must be dissolution into the lipoid substance 
of the cell-wall before the substance can pass on further, 
then even the most rapid osmosis would be a slow procedure. 
But even admitting dissolution into the lipoid substance as 
comprehensible, it is impossible to understand why the 
lipoid substance should not hold this dissolved substance all 
the more firmly, the more forcibly it has attracted it; 2. ¢,, 
why the substance should be passed on to the interior of the 
cell in direct proportion to the degree of its solubility. It is 
above all impossible to understand how water can penetrate 
membranes more rapidly than any other substance, since in 
its case there can be no question of great solubility in lipoid 
substances. It is even demonstrable in the case of kidney 
secretions and other secretory phenomena, that among other 
substances salts penetrate into the interior of the cell, a fact 
irreconcilable with Overton’s theory ; further, the experi- 
ments which have been made with diaphragms point to the 
conclusion that it is not the content of lipoid which determines 
the sequence of osmotic velocity. | 
Though these negative objections are weighty enough, the 
observations that now follow establish still more conclusively 
the fallacy of Overton’s and H. Meyer’s theories, in so far as 
they concern the causes of osmotic velocity. 
My own long-continued researches on the constants of capil- 
larity of substances—especially solutions t—have led to the 
following simple result:— The greater the osmotic velocity of a 
substance soluble in water, the more this substance reduces the 
capillarity constant of water. Substances that cannot penetrate 
* Note during the time of correction: My ideas concerning these 
objections need a certain restriction; compare my papers in Pfliiger’s 
Archiv d. Physiologie, Novy. or Dec. 1904. 
+ Compare especially Ler, d. d.chem. Ges. xvii. p. 2294 (1884) ; Journ. 
prakt. Chem, xxxi. p. 177 (1885), and Ann. Chem. Pharm. celxy. p. 27. 
