IMBIBITION AND ENDOSMOSIS. 471 



other circumstances which have a marked influence upon 

 imbibition, is temperature. It is a familiar fact that dried 

 animal membranes may be more rapidly softened in warm 

 than in cold water ; and with regard, to the imbibition of 

 liquids by sand, the researches of Matteucei and Cima have 

 shown an immense increase at a moderately elevated tem- 

 perature. 1 While nearly all the structures of the body 

 will imbibe liquids, after desiccation, the membranes through 

 which the processes of absorption are most active are, as a 

 rule, most easily permeated; and we shall see when we 

 come to study the mechanism of the passage of liquids 

 through these membranes, that the character of the liquid, 

 the temperature, etc., have a great influence upon the activ- 

 ity of this process. For example, all liquids which have a 

 tendency to harden the tissues, such as saline solutions, alco- 

 hol, etc., pass through with much less rapidity than pure 

 water. These facts will be found particularly interesting in 

 connection with experiments on the passage of liquids 

 through membranes, in experiments on endosmosis with arti- 

 ficial apparatus. 



Mechanism of the Passage of Liquids through Membranes. 



The attention of physiologists was first directed to this- 

 subject by the researches of Dutrochet, in 1826. 2 Though 

 not by any means the first to observe the phenomena which 

 he described under the name of endosmosis, to Dutrochet is 

 generally ascribed the honor of having first indicated the 

 applications of the laws of endosmosis to the nutrition of 

 plants and animals. Undoubtedly, Dutrochet was the first 



1 MATTEUCCI, Lemons sur les Phenomenes Physiques des Corps. Vivants, Paris, 

 1847, p. 23. 



2 The most complete account of these experiments is contained in a collection 

 of memoirs published by Dutrochet, in 1837, entitled Memoires pour servir d 

 VHisloire Anatomique et Physiologique des Vegetaux et des Animaux, tome i., pp. 

 1-99. A pretty full account is also given by Dutrochet in the Cyclopaedia of 

 Anatomy and Physiology, article Endosmosis, London, 1836-1839, vol. ii., p. 98. 



