ADAPTATION IN CRYSTALS. 337 



it is determined by this inner original formative tendency, 

 is the result of the specific and definite way in which the 

 smallest particles of the crystallizing matter unite together 

 in different directions according to law. That independent 

 inner formative force, which is directly inherent in the 

 matter itself, is directly counteracted by a second formative 

 force. The external constructive force, or the external 

 formative tendency, may be called Adaptation in crystals as 

 well as in organisms. Every crystal individual during its 

 formation, like every organic individual, must submit and 

 adapt itself to the surrounding influences and conditions 

 of existence of the outer world. In fact, the form and size of 

 every crystal is dependent upon its whole surroundings, for 

 example, upon the vessel in which the crystallization takes 

 place, upon the temperature and the pressure of the air 

 under which the crystal is formed, upon the presence or 

 absence of heterogeneous bodies, etc. Consequently, the 

 form of every single crystal, like the form of every single 

 organism, is the result of the interaction of two opposing 

 factors — the inner formative tendency, which is determined 

 by the chemical constitution of the matter itself, and of the 

 external formative tendency, which is dependent upon the 

 influence of surrounding matter. Both these constructive 

 forces interact similarly also in the organism, and, just as in 

 the crystal, are of a purely mechanical nature and directly 

 inherent in the substance of the body. If we designate the 

 growth and the formation of organisms as a process of life, we 

 may with equal reason apply the same term to the developing 

 crystal. The teleological conception of nature, which looks 

 upon organisms as machines of creation arranged for a 

 definite purpose, must logically acknowledge the same also 



