BOOK II. 



OF THE PRIMORDIAL PHENOMENA OF LIFE. 

 CHAPTER I. 



OF NUTRITION. 



WE cannot form a precise idea of the mechanism of nutrition, 

 unless we have thoroughly present to our mind the general laws 

 of diffusion and those of osmosis, especially between crystalloids 

 and colloids. 



We know that two solutions of different density, put separately 

 into a diffusion vessel and consequently in contact only on a 

 small surface, mingle by degrees intensely, to such a point indeed 

 that after a given lapse of time, the blending has everywhere an 

 identical composition. 



We also know that every substance has a degree of special 

 diffusibility, and that generally the colloidal substances have a 

 diffusibility infinitely inferior to that of the crystalloidal 

 substances. A glance at the following table furnishes a complete 

 idea of this difference : 



QUANTITIES DIFFUSED IN EQUAL TIMES. 



Chlorure of Sodium 58,68 



Sulphate of Magnesia 27,42 



Nitrate of Soda , . . 51,56 



