140 Biochcmical Proceedings, Hygienic Congress [Sept. 



The distribution of soluble salts in living cells and the force^ 



Controlling it 



ARCHIBALD B, MACALLUM 



1. The distribution of salts in living matter is held to be due to 

 the forces that make the distribution of salts uniform in an ordinary 

 Solution. These forces are the same as those which determine the 

 distribution of the molecules of a gas in an enclosed space. Conse- 

 quently, in a living cell the salts are supposed to be uniformly dis- 

 tributed throughout the fluid of the cytoplasm, that is, the osmotic 

 force, or the pressure exercised by the molecules and ions through- 

 out the fluid, is due to this uniform distribution of the solute 

 throughout the System. The quantity of a soluble salt present in 

 living matter is, therefore, a measure of the osmotic pressure therein 

 and hence exchange between the salts within and those without 

 would, in all cases, if the cell membrane were permeable, develop 

 so as to ad just the pressure equally within and without the cells. 



2. This conception leaves wholly out of account the action of 

 surface tension. Every particle of the colloid of which living mat- 

 ter is composed presents to the fluid in which it is suspended an In- 

 terface where the surface tension of the fluid is lower than such 

 a fluid has at its free surface. In consequence the Gibbs-Thomson 

 principle comes into Operation and there results a condensation of 

 the molecules and ions of the solutes on the Interfaces of all par- 

 ticles. As the united interfacial surfaces must, in relation to the 

 total volume of the Solution or fluid, present a very great area, a 

 very large proportion of each of the solutes must be so Condensed, 

 and the general concentration is, accordingly, greatly reduced or 

 brought to the vanishing point. This would reduce the osmotic 

 pressure due to such solutes to a very low value or even to nil. 



3. The degree to which concentration on surfaces or on In- 

 terfaces obtains depends on the degree of diminution of the tension 

 of the fluid at an Interface, but it also depends on the nature of the 

 solute, for the concentration in case of certain salts greatly exceeds 

 the value demanded by the Gibbs equation, while in other salts the 

 ascertained value approximates the theoretical value. 



4. Such surface condensation of the salts of living matter can. 



