202 LIFE AND DEATH. 



only form of equilibrium that this substance can 

 assume under the given conditions, just as the cube is 

 the crystallized form of sea salt, the only state of 

 equilibrium of chloride of sodium in slowly evaporated 

 sea water. Thus the problem of the living form is 

 reduced to the problem of the living substance, which 

 seems easier; and at the same time the biological 

 mystery is reduced to a physical mystery. It is clear 

 that this way of looking at things simplifies pro- 

 digiously and, we must add, simplifies far too much 

 the obscure problem of the relation of form to 

 substance, simultaneously in the two orders of science. 

 This may be summed up in a single sentence: 

 There is an established relation between the specific 

 form and the chemical composition: the chemical 

 composition directs and implies the specific form. 



We need not now examine the basis of this opinion. 

 If it is nothing but a verbal simplification, a unifica- 

 tion of the language applied to the two orders of 

 phenomena, it implies an assimilation of the mechan- 

 isms which realize them. To the organogenic forces 

 which direct the building up of the living organisms 

 it brings into correspondence the crystallogenic forces 

 which group, adjust, equilibrate, and harmonize the 

 materials of the crystal. 



When it is a question of the application of a 

 principle such as this, in order to test its legitimacy 

 we must always return to the experimental founda- 

 tions. Let us imagine, for example, a simple body, 

 such as sulphur, heated and brought to a state of 

 fusion that is to say, homogeneous, isotropic, in an 

 undisturbed medium the only change in which will 

 be a very gradual cooling down. These are the 

 typical crystallogenic conditions. The body would 



