MODIFICATIONS OF END03MO3IS. 495 



solution of 1*035 density, charging his tube, which was bent 

 in the form of a V, with a column of mercury one inch in 

 height. At the end of twenty-eight hours, the ascent of the 

 column of mercury was arrested at ten inches and seven 

 lines. Using a saccharine solution of 1*070 density, and 

 charging the tube with ten inches of mercury, in thirty-six 

 hours, the elevation of the mercury had become arrested at 

 twenty-two inches and ten lines. In a third experiment, the 

 density of the saccharine solution was 1*040, and the tube was 

 charged with twenty-two inches of mercury. The experi- 

 ment lasted for three days, and the elevation of the mercury 

 was forty-five inches and nine lines. All these experiments 

 were made at the same temperature (69 Fahr.) 1 



These experiments, which have frequently been repeat- 

 ed in a more or less modified form, illustrate three points : 

 first, the great force of the endosmotic current ; second, the 

 fact that this current may be arrested by a sufficient amount 

 of pressure ; for in the second experiment, after endosmosis 

 had ceased and the mercury had been elevated nearly 

 twenty-three inches, the density of the liquid in the endos- 

 mometer had been reduced from 1*070 to 1*053, when, with- 

 out pressure, the current would undoubtedly have continued ; 

 and finally, these experiments illustrate the fact that, within 

 certain limits, the force of the endosmotic current is in pro- 

 portion to the concentration of the solution in the endos- 

 mometer. 



Even in the large arteries, the pressure of blood seldom 

 exceeds six inches of mercury, and it is much reduced 

 when the blood passes into the capacious system of capillary 

 vessels and thence into the veins. This amount of pressure, 

 then, though capable of exerting a marked influence upon 

 the rapidity of absorption, would not materially oppose the 

 introduction of liquids of low density^ even were its effects 

 not counteracted to a certain extent by other circumstances * 

 for it must be remembered that the blood has a specific 



1 DUTROCHET, op. cit, tome i., p. 38. 



