ENDOSMOSIS. 



99 



cending branch containing a column of mer- 

 cury, which was raised by the interior fluid 

 of the endosmometer in proportion as the en- 

 dosmosis increased the volume of this fluid.* 

 By means of these two instruments I have 

 found that the velocity and strength of endos- 

 mosis follow exactly the same law. Both are 

 in relation to the quantities which express, in 

 two comparative experiments, the excess of 

 density of two dense fluids contained in the 

 endosmometerj above the density of water, 

 which in these two experiments is exterior to 

 the instrument. Thus, for example, in putting 

 successively into the same endosmometer, syrup 

 of which the density is 1.1, and syrup of which 

 the density is 1.2, and in plunging in both 

 cases the reservoir of the endosmometer into 

 pure water, you obtain in the first case an en- 

 dosmosis, of which the strength and velocity 

 are represented by 1 , and in the second case an 

 endosmosis, of which the strength and velocity 

 are represented by 2 ; that is to say, by the 

 numbers relative to the fractionals 0.1 and 0.2, 

 which express the excesses of density of the 

 two solutions of sugar above the density of 

 water, which is 1 . I have ascertained by ex- 

 periment that the strength of endosmosis is 

 such that, with syrup of which the density is 

 1.11, and an endosmometer, the opening of 

 which is closed by three pieces of bladder, one 

 over the other, you obtain an endosmosis which 

 raises the mercury to 1 metre 238 millimetres, 

 or 4.5 inches 9 lines, which is equivalent to an 

 elevation of water of 16 metres 77 centimetres, 

 or 51 feet 8 inches. It follows from this, that 

 in employing syrup, of which the density was 

 1.33, (its ordinary density,) you would obtain 

 an endosmosis, the strength of which would be 

 capable of raising water more than 150 feet. 



Fluids of a different nature have, with refer- 

 ence to endosmosis, properties which are in no 

 way in proportion to their respective densities. 

 Thus sugar- water and gum- water of the same 

 density, being put successively into the same 

 endosmometer, which is plunged into pure 

 water, the former produces the endosmosis 

 with a velocity as 17, and the latter with a 

 velocity as 8 only. I have seen, in the same 

 manner, a solution of hydrochlorate of soda 

 and a solution of sulphate of soda of the same 

 density, put successively in the same endosmo- 

 meter surrounded with pure water ; the velo- 

 city of the endosmosis produced by the solu- 

 tion of sulphate of soda is exactly double that 

 of the endosmosis produced by the solution of 

 hydrochlorate of soda. These results are inva- 

 riable, and I am persuaded that if 1 have ever 

 obtained a different result, the experiment has 

 been defective. 



I have made several experiments since with 

 gelatinous and albuminous waters placed suc- 

 cessively in the same endosmometer, surround- 

 ed with pure water, which produced endos- 

 mosis severally in the proportion of 1 to 4 ; 

 so that the albumen had four times more power 

 of endosmosis than the gelatine. I have seen 



* See my work entitled, Nouvelles Recherches sur 

 I'endosmose et 1'exosmose, &c. 8vo. Paris, 1828. 



by another experiment that the power of eii- 

 dosmosis of syrup is to the power of endos- 

 mosis of albuminous water of the same den- 

 sity, as 11 is to 12. 



All alkalies and soluble salts produce en- 

 dosmosis; so do all acids, but each with spe- 

 cial phenomena, which will be noticed by and 

 by. These chemical agents in general occasion 

 an endosmosis of short duration only, when the 

 endosmometer is closed with a portion of an 

 animal membrane. Organic fluids alone, which 

 are not very sensibly either acid or alkaline, or 

 salt, produce lasting endosmosis, which, in- 

 deed, does not stop until the fluids are altered 

 by putrefaction, when they become charged 

 with sulphuretted hydrogen. I have shown that 

 when an endosmometer is closed with a thin 

 plate of baked clay instead of the animal mem- 

 brane, the endosmosis which a saline solution 

 produces, and which would have stopped in a 

 few hours with the animal membrane, continues 

 to go on indefinitely with the baked clay. 



The property of destroying endosmosis may 

 be considered as belonging to all chemical re- 

 agents, but merely on account of their sus- 

 ceptibility to enter into combination with the 

 permeable partition of the endosmometer. Thus 

 all acids, alkalies, soluble salts, alcohol, &c. 

 being disposed to combine with the elements of 

 organic membranes, destroy endosmosis, al- 

 though they had induced it before their complete 

 combination with the elements of the membrane 

 had taken place ; and it is not until this combi- 

 nation is complete that endosmosis ceases. Or- 

 ganic fluids, which have no chemical action upon 

 the elements of the membrane of the endosmo- 

 meter, ought not, consequently, to tend to the 

 destruction of endosmosis, unless some change 

 should take place which should give them a 

 chemical action, such as they usually acquire 

 by decomposition, when they usually become 

 charged with sulphuretted hydrogen. 



My earlier experiments tended to show that 

 carbonate of lime (chaux carbonatee) reduced 

 to thin laminae, and employed to close an en- 

 dosmometer, is totally without the power of 

 producing endosmosis ; my latter experiments 

 have somewhat modified this conclusion. After 

 having vainly employed laminae of carbonate 

 of lime of greater or less thickness, I finished 

 by making use of one of white marble, two 

 millimetres in thickness, but with no better 

 success. Without carrying my experiments 

 further, I concluded that porous carbonate of 

 lime was totally unapt to excite endosmosis. 

 This conclusion having, notwithstanding, left 

 some doubts in my mind, I again took the same 

 plate of marble with the intention of measuring 

 its permeability to water, compared with the 

 various degrees of thickness which I could give 

 it, and of renewing, at the same time, my at- 

 tempts to make it produce endosmosis. Having 

 closed an endosmometer with this plate of mar- 

 ble, I filled the reservoir and the tube of the 

 instrument with pure water, and suspended it 

 over a vessel filled with water, in which the plate 

 of marble only was immersed. If the marble 

 had been permeable to water, the fluid con- 

 tained in the endosmometcr would have flowed 



H 2 



