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on Osmosis, Solubility, and Narcosis. 709 
theory of diffusion, the salt particles or the ions, in virtue 
of their ‘‘ osmotic pressure,” migrate into the pure solvent. 
According to the conception of osmotic phenomena set forth 
here, it is not the particles of the salt solution that migrate 
into the pure solvent; but, on the contrary, it is the pure 
solvent which, by virtue of its low surface-tension, migrates 
into the salt solution. This conception of the phenomena of 
diffusion leads to significant physiological consequences *. 
Further, if two different liquids, capable of mutual dissolu- 
tion, be brought into contact, or if a solid substance be in 
contact with a solvent, the “ solution-tension ” will depend chiefly 
on the difference between the surface-tensions. 
It is now clear why a much greater quantity of ether or 
amyl alcohol dissolves in water, than of water in ether or amyl 
alcohol. Further, as Hulet’s t experiments have demonstrated, 
a coarse powder does not act in the same way as a fine powder 
when treated with solvent. 
On the basis of this theory of solubility, it is to be antici- 
pated that when a liquid ora solid substance dissolves in a 
solvent, the surface-tension of the solution will never fall 
below that of the dissolving substance. Tor if, through the 
increasing concentration of the solution, the surface-tension 
of the solution should approach nearer and nearer to that of 
the pure solvent, a point will finally be reached at which the 
surface-tensions of solution and dissolving substance are equal. 
And then the solution will be saturated. 
If, for instance, methyl and ethyl alcohol, in whatever 
proportion, are not “ miscible”? with water, but are soluble in 
it, it must be concluded that the constants of capillarity of all 
the solutions should be without exception greater than those 
of the pure alcohols: this is actually the case. On the other 
hand, the fact that amyl alcohol is only sparingly soluble in 
water must be attributed to the amyl alcohol lowering the 
capillary height of water to such an extent, that the saturated 
solution has very nearly the capillary height of pure amyl 
alcohoi. 
The following Table illustrates these contentions. ¢ is the 
temperature of observation, h, the capillary height of the 
saturated aqueous solution, h, that of the organic substance 
saturated with water. The capillary height of water in the 
tubes used was 92°5 mm. at 18°C. From these data may be 
calculated the absolute constant, which does not concern us 
here. 
* Compare Pfluger’s Aree d. Physiol. Nov. or Dec. 1904. 
+ Hulet, Zeitschr. physik, Chem, xzxvii. p. 885 (1901). 
