vi PREFACE 



decomposed elements with simpler elements found in its 

 environment, so that although always in an unstable equilib- 

 rium, it constantly retains its initial composition and 

 structure. 



It is easy to conceive that if the conditions of this " nutri- 

 tion" of the "micelle" depend on what is provided by the 

 surrounding matter, the "micelle" may decrease or increase 

 in volume; that is to say, it may decompose faster or slower 

 than it is constructed . When a sufficient quantity of building 

 material is at hand, the increase in volume will predominate; 

 and when its volume will have reached certain limits capable 

 of modifying its conditions of normal nutrition, the "micelle" 

 will split into two equal parts. 



It is this multiplication which together with nutrition 

 constitutes life. 



The "micelle" develops as an individual and as a species; 

 in its evolution it must obey the law which obliges every 

 substance to replace in its complexes, the less stable or more 

 soluble compounds by more stable or less soluble compounds. 



The "micelle" will "age" because, as its elements become 

 more stable, substitution becomes slower and slower; it will 

 "die" when stabilization will have passed beyond certain 

 limits, because a certain rapidity of exchange, producing a 

 certain amount of heat, in a given time, is an indispensable 

 condition of life. 



The individual may die under these conditions; the species 

 likewise, because the child-" micelles" will inherit the degree 

 of stability acquired by the parent-" micelles." 



When a cell's "micelles" find in their surrounding medium 

 elements of which they are composed themselves, or other 

 elements for which their own elements have no affinity, they 

 can find nourishment and can develop in a normal manner; 

 but when, on the contrary, they find strange elements, 



