544 Intelligence and Miscellaneous Articles. 



is very commonly met with in the South Pacific, and has almost an 

 indefinite range. As regards hoth animal and shell, it in many 

 points resembles a miniature Natica. The shell is few-whorled, with 

 small compressed spire and ventricose mouth ; the operculum pauci- 

 spiral and well-marked with the lines of growth. The foot is not 

 unlike a broad and square-toed shoe in form, receiving or bearing 

 the remainder of the animal and the shell. The shoe-upper, as it 

 were, presents two rounded lateral lobes which lie over the anterior 

 part of the shell, like the mentum of Natica. The little animal 

 creeps on its foot with great rapidity, appearing rather to slide along 

 than progress by a vermicular movement, and by spreading out and 

 hollowing this organ at the surface of the water, as a freshwater 

 Lymnsead forms a boat of its foot, it buoys up its tiny body and is 

 cast abroad on the face of the ocean. 



LXXVI. Intelligence and Miscellaneous Articles. 



EXPERIMENTS RELATING TO ENDOSMOSE. BY M. LHERMITE. 



THE term endosmose has been applied by Dutrochet to the pas- 

 sage of one liquid towards another through a septum affording 

 less resistance to the passage of one liquid than to that of the other. 



From analogies which were erroneously supposed to exist between 

 this phamomenon and the experiment made by Porret, endosmose 

 was attributed to electrical action. 



Poisson explained the phsenomenon as a result of capillarity, but 

 he did not ascribe to the attraction of solids for liquids any other 

 function than that of determining the occupation of the numerous 

 small channels, of which the septum may be regarded as constituted, 

 by one liquid in preference to another, and of preventing the inter- 

 ruption of the liquid threads. He referred the ulterior action to the 

 mutual attraction of the two liquids. 



Dutrochet attributed, in his later memoirs on this subject, much 

 to the reciprocal chemical action of the liquids, but he never attempted 

 to explain the mode in which the membrane acted, always being 

 inclined towards the electrical theory. 



Mr. Graham has recently been led to the conclusion, that the 

 alteration of the septum appears to be a condition indispensable for 

 the manifestation of the osmotic force. According to him, one of 

 the surfaces of the membrane is acid, the other basic, and this state 

 is connected with the progressive decomposition of its substance. 



M. Lhermite considers that he has demonstrated, by means of his 

 own observations and those of his predecessors, that endosmose is 

 not produced by any peculiar force, but that it is a result of affinity 

 (chemical action), taking the widest signification of that term, and 

 including capillary attraction. 



Poisson, who treated the question as a mathematician, and not 

 experimentally, admits that when the movement has once commenced, 

 the septum has no further share in the action ; but if the action 

 takes place solely between the liquid A, which is actually absorbed 



