DIVISION III 

 PHYSICAL INFLUENCES 



CHAPTER I 

 WATER AS A PHYSICAL FACTOR* 



It has been indicated already that water has the capacity as a 

 solvent way beyond any other substance; it has a function, closely 

 associated with its solvent powers as a carrier, in which solution and 

 mechanical mixture are equally important; it possesses the property 

 of diffusion, which enables its solutions to extend where other solvents 

 find no entrance; it possesses much surface energy, having a very high 

 rating; and it fosters ionization, the full value of which in life's reactions 

 is not known. Living cells have been shown to consist of a high per- 

 centage of water. It appears as if water were the body-medium for all 

 physiological reactions. [See pp. 187] 



OSMOTIC PRESSURE. In the organic world we find very commonly 

 membranes which will allow water to pass through but retain some 

 compounds dissolved in the water. Such so-called semi-permeable 

 membranes are found surrounding the protoplasm of cells. They are 

 not the cell wall, but separate the protoplasm from the cell wall. 

 Similar properties are found in parchment paper, pig's bladder, and 

 other organic membranes. 



If a salt solution is poured in water, the two liquids will mix in a 

 short time and soon every smallest portion of the mixture will have the 

 same concentration. If a salt solution and water are separated by a 

 membrane which does not allow th* salt to pass, the water will go 

 through the membrane toward the salt with a certain amount of 

 pressure. This pressure depends upon the nature of the dissolved 

 substance as well as upon its concentration. 



The pressure increases in direct ratio with the number of molecules 

 in solution. Therefore, a compound with large molecules (cane sugar) 



* Prepared by Otto Rahn. 



263 



