142 STUDIES IN ELECTRO-PHYSIOLOGY: 



in the following statement, which does but repeat exactly 

 the ideas of Faraday : Bodies are composed of elements 

 or ions charged, some with positive, others with negative 

 electricity, and united at first in the neutral state. Under 

 the influence of the battery current, the neutral molecule 

 dissociates into positive and negative elements, which go to 

 the poles of contrary names. The decomposition of a 

 neutral salt may be represented by such an equation as : 



" When an ion leaves a solution in order to precipitate 

 itself at an electrode charged with electricity of contrary 

 sign by reason of the attraction exercised between two 

 opposite electric charges it then becomes neutralised, 

 which means that it receives from the electrode a charge 

 exactly equal but of contrary sign to that which it before 



" Adopting the theoretical ideas put forward by 

 Clausius, Arrhenius recognised that an electric current was 

 in no way necessary to produce the dissociation of com- 

 pounds into ions. In dilute solutions the bodies dissolved 

 must be separated into ions by the mere fact of solution. 

 When the electrodes of a battery are plunged into such 

 solution, the ions must simply be attracted by them 

 the positive ions by the negative pole, and the negative ion 

 by the positive pole." (Le Bon.) 



According to Czapec, in any solution the degree of this 

 dissociation depends on the nature of the salt, the tempera- 

 ture of the solution and its strength. Acids and alkalies 

 when diluted to one milligramme in one litre of water are 

 entirely broken up into ions and cease to exist as acids and 

 salts. Halliburton tells us that the proportion of inorganic 

 salts in the blood plasma is 8-55 in 1,000, or approximately 

 0-9 per cent. ; but that is the sum total of all the salts. 



