284 LIFE AND DEATH. 



The crystalline particle, the element of the crystal, 

 is therefore a certain molecular complex that repeats 

 itself identically and is identically placed at the 

 nodes of the parallelopipedic network. It has been 

 given different names well calculated to produce 

 confusion the crystallographic molecule of Mallard, 

 the complex particle of other authors. Some have 

 separated this element into subordinate elements 

 (the fundamental particles of Wallerant and of 

 Lapparent). 



These very general outlines will suffice to show 

 how complex and adjustable is the organization of 

 the crystalline individual, which in spite of its 

 geometric regularity and its rigidity, may be com- 

 pared with the still more flexible organization of the 

 living element. The mineral individual is more 

 stable, more labile i.e., less prone to undergo change 

 than is the living individual. We may say with 

 M. Lapparent that " crystallized matter presents the 

 most perfect and stable orderly arrangement of 

 which the particles of bodies are susceptible." 



Law of Relation of Specific Form to Chemical 

 Constitution. Crystallization is a method of acquiring 

 specific form. The geometrical architecture of the 

 mineral individual is but little less wonderful or 

 characteristic than that of the living individual. Its 

 form is the result of the mutual reactions of its 

 substances and of the medium in which it is pro- 

 duced ; it is the condition of material equilibrium 

 corresponding to a given situation. This idea of a 

 specific form belonging to a given substance under 

 given conditions must be borne in mind. We may 

 consider it as a kind of principle of nature, an 

 elementary law, which may serve as a point of 



