ENDOSMOSE AND EXOSMOSE. 265 



and plants are mere aggregations of capillary 

 tubes and pores, through which many hundred 

 million tons of sap are forced up by the power of 

 vital attraction, under the immediate agency of 

 solar heat, and that all the phenomena of life, 

 (which result from an attraction between liquids 

 and solids,) are arrested by cold. The principal 

 difference between ordinary capillary attraction, 

 and the capillary circulation of plants and ani- 

 mals, is, that the vessels or tubes of the latter 

 are almost inconceivably small, while the force 

 of all attraction is inversely as the distance ; 

 hence the force with which a moistened rope 

 contracts, and raises immense weights ; or the 

 force and velocity with which blood and sap are 

 drawn through their minute vessels. 



The mutual interchange of two different li- 

 quids, separated by a membrane or other porous 

 body, which has been referred by Dutrochet to 

 the operation of a peculiar force, termed by him 

 endosmose, and exosmose, according to their direc- 

 tion, is doubtless a modification of capillary at- 

 traction, or of the force which causes all che- 

 mical combinations. 



There is another general fact which connects 

 the theory of capillary attraction with that of 

 heat. 



Those bodies which have the least attraction 

 for caloric, have the least power of absorbing 

 water, such as furs, silks, woollens, cottons, 

 resins, sulphur, phosphorus, and other non-con- 



