84 THE THEORY OF IONS 



into the liquid, and it is these particles or metallic 

 ions in the fluid which contain the positive electric 

 charge. If we imagine the metal plate to be 

 divided under the water into very fine particles of 

 metallic dust, they will, by virtue of their minute- 

 ness and the electro-static condition induced in 

 them, remain suspended for an indefinite length of 

 time. Such is a colloidal solution. It is a sus- 

 pension of electrically charged particles, each of 

 which is an electrode. It is an example of colloids 

 in general. The chief laws and the differences 

 between colloids are all referable to the number, 

 size and electrical charge of the particles. Although 

 such particles appear to be unaffected by gravity, 

 they are affected by electrical changes, and clumping 

 or precipitation can be produced. 



It is to such particles in particular that I have 

 ventured to apply the name of Meres. They are 

 not exactly inert particles ; they possess energy, 

 part of which is potential, and part is already 

 kinetic as shown by their electrical charge, by their 

 chemical combinations, and in other ways. In col- 

 loidal bodies such combinations appear to be always 

 between ions and meres, and the influence exerted 

 by one upon the other is among the facts demon- 

 strated by a study of the chemistry of the colloids ; 

 and it is to such combinations that many physio- 

 logical processes are due. 



The chemistry of the colloids is therefore exceed- 

 ingly important both for biology and therapeutics, 

 for " there exists no life process that is not accom- 

 panied by changes in the colloidal and crystalloidal 

 substances. ' ' Some of the laws of general physiology 



