CHAPTEK XYI 



I 



IMBIBITION AND ENDOSMOSIS. 



General considerations Imbibition by animal tissues Mechanism of the passage 

 of liquids through membranes Observations anterior to those of Dutro- 

 chet Experiments of Dutrochet Conditions necessary to endosmosis and 

 exosmosis Influence of membranes upon osmotic currents Capillary attrac- 

 tion Imbibition by porous substances Endosmosis through porous septa 

 Endosmosis through animal membranes Endosmosis through liquid septa 

 Electrical theory of endosmosis Influence of different liquids upon osmotic 

 currents Diffusion of liquids Endosmotic equivalents Modifications of en- 

 dosmosis Modifications due to the extent and the thinness of the permeable 

 membrane Modifications due to pressure and the movements of liquids 

 Modifications due to variations in temperature Modifications induced by elec- 

 tricity Application of physical laws to the function of absorption Transu- 

 datron. 



THE ideas of physiologists concerning the mechanism of 

 absorption have become radically changed since the begin- 

 ning of the present century ; and it is now generally admitted 

 that this process takes place chiefly by blood-vessels, and that 

 the absorbents have no orifices endowed with the wonderful 

 elective power which was attributed to them by the older wri- 

 ters. This involves the passage of liquids through the coats 

 of the blood-vessels and lymphatics ; a process which has been 

 the subject of numerous experiments, resulting in the devel- 

 opment of many important physical laws capable of applica- 

 tion to physiological absorption. At the present day, the 

 history of absorption is not complete without a consideration 

 of the laws of imbibition and endosmosis. In accordance 

 with the plan which we have endeavored to follow in the 



