MEMOIR XXVI.] CAPILLARY ATTRACTION, ETC. 



353 



the alcohol simultaneously passes outward to mix with 

 the water, it is said to exhibit exosmosis. 



In Fig. 78 is represented the endosmometer of Dutro- 

 chet. It consists of a small blad- 

 der, #, tightly tied to a tube, d, 

 open at both ends, and bent as 

 seen in the figure at c; the blad- 

 der being completely filled with 

 alcohol, and the tube to some 

 such point as d, the arrangement 

 is placed in a vessel of water, ee j 

 almost immediately the level of 

 the liquid will be seen to be ris- 

 ing, the bend of the tube is 

 reached, and one drop after an- Fig - 78 - 



other falls from the open end into the receiver, b. And 

 this continues until the liquids inside and outside of the 

 bladder are uniformly commingled. 



In these results there is nothing more than should 

 take place on the ordinary principles of capillary action. 

 The pores of a bladder are only short capillary tubes, 

 into which water readily finds its way, because it can 

 wet the substance surrounding the pores. If the blad- 

 der be distended with air and sunk under water, al- 

 though the water will fill the pores, it will not exude 

 from them and accumulate in the interior of the blad- 

 der; for, as we have seen, a capillary tube cannot estab- 

 lish a continued current or flow. But the case becomes 

 totally different when the bladder is filled with alcohol ; 

 for then as fast as the water presents itself on the inner 

 end of each pore it is dissolved away by the alcohol, and 

 the necessary condition for a continuous flow is complied 

 with. Meantime through the pore itself a little alcohol 

 passes in the opposite w r ay by infiltrating through the 

 incoming water, provided that the current be not too 



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