APPLICATION OF PHYSICAL LAWS TO ABSORPTION. 503 



which it must be confessed that there exists very little defi- 

 nite information in explanation of this phenomenon. The 

 penetration of membranes by fatty particles must be re- 

 garded as one of the points which cannot be fully explained 

 by the laws of endosmosis. 



There are certain experiments on absorption, in the living 

 body, to which a great deal of importance was attached by 

 Longet, which are seemingly in opposition to physical laws. 

 This author states that when solutions of sugar of different 

 densities are secured in isolated portions of the intestine of a 

 living animal, the denser solutions are absorbed with as 

 much rapidity as those which are less concentrated. He also 

 shows that saline solutions of greater density than the blood 

 are absorbed in the living animal, when, according to physi- 

 cal laws, the current should take place in the opposite 

 direction. 1 The view that these facts are in opposition to 

 physical laws is very successfully controverted by Milne- 

 Edwards. This author, referring to some experiments by 

 Von Becker in support of his position, asserts that there is 

 first an exosmosis of the watery portions of the blood to these 

 dense solutions, with a feeble penetration of the solutions into 

 the blood-vessels, until, by the laws of diffusion, the solutions 

 become so diluted as to be taken into the circulation. 2 Such 

 an action as this could not take place between two saline solu- 

 tions in an endosmometer, for both currents would cease when 

 the liquids became of equal density ; but it has been shown 

 that after endosmosis in an endosmometer has ceased, it may 

 be again induced by simply agitating the liquids. In phys- 

 iological absorption, the motion is constant and very rapid, 

 and solutions in their passage along the alimentary canal are 

 continually exposed to fresh absorbing surfaces. Further- 

 more, the albumen of the blood, which is very slightly ex- 

 osmotic, will attract an endosmotic current from liquids 

 even when they are of the same density. The kind of ac- 



1 See page 464. 



3 MILNE-EDWARDS, Lemons sur la Physiologic, Paris, 1859, tome v., p. 192. 



