CHAPTER V. 

 Specific Form. Living Bodies and Crystals. 



§ I. Specific form and chemical constitution — The wide dis- 

 tribution of crystalline forms — Organization of crystals — 

 Law of relation between specific form and chemical 

 constitution — Value of form as a characteristic of brute 

 and living beings — Parfentage, living beings and mineral 

 parentage — Iso-morphism and the faculty of cross-breeding 

 — Other analogies, i^ 2. Acquisition and re-establishment 

 of the specific form — Mutilation and regeneration of crystals 

 — Mechanism of reparation. 



§ I. Specific Form and Vhemical Constitution. — In 

 the enumeration which we have made of the essential 

 features of vitality there are three that are, so to 

 speak, of the highest value. They are, in the order of 

 their importance : — The possession of a specific form ; 

 the faculty of growth or nutrition ; and finally, the 

 faculty of reproduction by generation. By restricting 

 our comparison between brute bodies and living 

 bodies to these truly fundamental characters we 

 sensibly restrict the field, but we shall see that it 

 does not disappear. 



Wide Distribution of Crystalline Forms. — The 

 consideration of specific forms shows us that in 

 the mineral world we need only consider crystallized 

 bodies, as they are almost the only ones that possess 

 definite form. In restricting ourselves to this category 

 we do not limit our field as much as might be sup- 



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