﻿106 MEIGS ON THE RELATION OF 



by snow-crystals, we find specimens from whose primitive rays are given off lateral 

 spines or branchlets in pairs, directly opposite to, and separated the same distance 

 from each other. One basal ray with its secondary spines is the fac-simile of all the 

 rest. Now this tendency to the repetition of precisely similar parts is seen not in the 

 formation of a crystal only, but also in the development of the highest plants, in 

 zoophytes and in the lower mollusca and articulata where it embraces entire groups 

 of organs. Thus in the highest forms of the Echinodermata, five precisely similar 

 rays are developed around a common centre. The same tendency is seen in the eight 

 or ten tentaculse which surround the mouths of the dibranchiate Cephalopoda. Similar 

 examples are presented by the Annelida. In all these instances it is evident that the 

 developing force has acted methodically from a common centre, towards the accom- 

 plishment of a definite end or object — the production of a special form. In classifi- 

 cation, form is of the highest value to the practical naturalist. But form is not 

 fundamental, it is merely secondary; it is the effect of the action of the developing 

 cause upon ponderable matter. Aided by a severe and cautious logic, the careful and 

 elaborate study of comparative morphology, it is reasonable to hope, will enable us 

 to advance from the known to the unknown, from the multitudinous forms of natural 

 objects to their physical cause. Moreover, it will probably lead to the discovery of 

 profound analogies between the organic and the inorganic worlds, — analogies mani- 

 fested through similarity in the modes of action of the formative or developing prin- 

 ciple. 



Crystallization naturally constitutes the first chapter in the history of comparative 

 morphology. A knowledge of crystallization is of prime importance to the chemist 

 and mineralogist in assisting them to arrange bodies in their natural groups; to the 

 natural philosopher in elucidating the laws of cohesive attraction ; to the physiologist, 

 since it promises to throw considerable light upon the function of a fundamental 

 physical agent, the analogy of whose method of action with that of the developing 

 principle in the organic world, will lead, if not to their identification, at least to more 

 definite knowledge of the phenomena of growth; to the physician, as it affords some 

 clue to the pathology of symmetrical diseases; and lastly to the philosophic naturalist, 

 from its relation to organic morphology, through which, perhaps, will be attained 

 that much desired result, the demonstrative proof of a great general or archetypal 

 plan of organization. 



A diligent and attentive inquiry into the rationale of the phenomena of isomorphism 

 and dimorphism would dissipate much of the mystery that hovers about the cause of 

 crystallization in general ; and even, perhaps, illuminate many obscure parts of organic 

 science. 



Towards the accomplishment of so desirable a result, an important step was made 



