46 Dialysis. 



Saturday, July 4th, 1868. 



The Forty-seventh Meeting of the Society was held at Mr. 

 Griffith's House. 



The Exhibitions were : 



Some rare Birds . . . . . . . . . . By Evans. 



Some Birds, kindly presented to the Society, by Mr. Bevan, in addition 

 to the former collection . . . . By Mr. Holmes. 



Nodal lines in glass plates when in a state of vibration ; a monochord. 



By Mb. Griffith. 



The President mentioned that Professor Huxley had bracketed 

 Evans and Balfour first, Everard being third, for the prizes offered 

 by Mr. Leaf, for Essays written during the holidays. 



Clarke then read a Paper on 



DIALYSIS. 

 Of which the following is an abstract. 



In this paper an account was given of Graham's investigations 

 of liquid diffusion, or the passage of substances like sugar, salt, &c., 

 through membranes of a gelatinous nature. The term dialysis is 

 applied by Graham to such phenomena. The membranes or 

 jellies permeated are called by him "Colloid" {k6\\t) glue), and the 

 substances which penetrate them are termed crystalloids ; sugar, 

 salt, alcohol are examples of the latter, starch, gelatine, albumen, 

 parchment paper, mucous membrane, of the former. 



A minute account of Graham's experiments was given, and a 

 few examples of dialysis were exhibited. 



Graham's explanation of the phenomena, described is, that 

 the colloids contain water in a state of weak chemical union, 

 and that a soluble crystalloid can separate this water from the 

 colloids, and thus obtain a liquid medium for its diffusion. 



The application of this discovery to the explanation of the 

 absorption of food from the digestive system, and the secretion of 

 glands and other functions of organic life was mentioned. 



Graham has also suggested the important aid of dialysis to 

 toxicologists in separating arsenic and other crystalloids from the 

 colloidal substances of the stomach in medico-legal cases. 



