822 M. Dutrochet's New Researches 



endosmose might be attributed to the plates of the crystallized 

 substance not being permeable. 



I was induced to believe that the negative results which I 

 obtained from all these experiments proceeded from my porous 

 plates being too thick. It was impossible to obtain these plates 

 as thin as the organic membranes ; and it appeared to me pro- 

 bable, that the electricity which produced endosmose was 

 owing to the near approximation of the two heterogeneous 

 fluids. 



In this belief, I endeavoured to procure very thin and po- 

 rous mineral plates. Slate appeared to me the most likely to 

 answer my purpose. By means of a slight calcination slate is 

 capable of being divided into extremely thin leaves. I obtain- 

 ed in this manner a plate of slate which was not more than one- 

 fiftieth of an inch thick. I adapted it to my apparatus, and 

 the experiment having been made as above described, I obtain- 

 ed a very evident, although very feeble, appearance of endos- 

 mose. The slight permeability of the slate to water was the 

 cause of the weakness of the endosmose. Encouraged by this 

 success, I prepared a plate of baked white clay of one twenty- 

 fifth of an inch in thickness, and I adapted it to my appara- 

 tus ; I obtained an endosmose sufficiently powerful, and but 

 little different from that which I should have obtained in the 

 same case with the organic membrane. Hence it is proved 

 that certain inorganic bodies are susceptible of producing en- 

 dosmose by means of heterogeneous fluids, in the same man- 

 ner as the organic membranes. I tried to adapt a plate of 

 white baked clay two-fifths of an inch in thickness to my ap- 

 paratus ; I again obtained an endosmose very quickly, which 

 surprised me greatly. I adapted to my apparatus another 

 plate of clay three-fifths of an inch in thickness; I obtained 

 again the endosmose, but it was very weak or very slow. This 

 ought to be attributed to the thickness of the porous plate 

 having diminished its permeability. These facts entirely 

 changed the opinion I had formed from my preceding expe- 

 riments respecting the necessity of having the porous plates 

 so extremely thin, in order to produce endosmose. They 

 showed me that it did not arise from their being too thick, 

 that the plates of freestone, of carbonate of lime, and sul- 

 phate of lime did not produce endosmose, but that it entirely 



