286 Dutrochet on the 



alternately to transmit two opposite currents : all the capillary 

 canals of the partition of the endosmometer would be occupied 

 by currents flowing in the same direction. 



Since the capillary action perfectly accounts for all the con- 

 ditions of the phenomenon of the endosmosis, it is evident 

 that the affinity of mixture of the liquids has no share in the 

 production of this phenomenon ; it exists, it is true, as an 

 accessory phenomenon, but has no dynamic effect. If the 

 miscible quality of the liquids be necessary to the existence 

 of the endosmosis, it by no means follows that their mixture 

 acts as a dynamic cause of the effect produced. Endosmosis 

 results from the opposed association of two unequal capillary 

 actions. Now the capillary actions of oil and of water mu- 

 tually destroy each other ; a tube, which has its interior sides 

 rubbed over with oil, will not occasion the capillary ascension 

 of water, so that there is not in this case any opposition of two 

 unequal capillary actions ; there is but one, and therefore 

 there is no endosmosis, 



The simple capillary action, which alone has been hitherto 

 known, is a force which never impels liquids beyond the sphere 

 of capillary action ; the double capillary action, which I have 

 discovered, impels the two opposing liquids in opposite direc- 

 tions across the capillary sphere of action, and tends to drive 

 them out in unequal quantities on each side. All the organic 

 animal or vegetable membranes, which may be used in closing 

 endosmometers, are eminently adapted to produce endosmosis. 

 Among the mineral substances, which may be used in very 

 thin plates for the same purpose, baked clay is the best adapted 

 to produce this phenomenon ; plates of carbonate of lime 

 scarcely produce it at all ; I was, indeed, disposed to believe 

 that the latter substance was totally incapable of' producing- it, 

 but, on repeating my experiments, I succeeded in obtaining 

 a very feeble, but still perceptible endosmosis with a plate of 

 white marble of the thickness of one millimetre. 



All the liquids which are susceptible of a chemical combi- 

 nation, with the permeable partition of an endosmometer, sus- 

 pend the endosmosis, after having produced it for a longer or 

 shorter period. Thus, when an acid, alkaline, or saline solu- 

 tion is placed in an endosmometer, an endosmosis is at first 



