RETROSPECT 



573 



Only in so far as specificity is ignored, but within this modest sphere 

 the knowledge acquired is most significant. The substratum in which 

 life is inherent is not a disperse phase with individual particles or 

 ultramicrons ; it possesses 2l structure. Its active centres, which control 

 development, are arranged in a given order. They are not intermingled 

 by mere laws of chance and Brownian molecular movement ; the fact 

 is rather that they arrange themselves into a delicate, very plastic and 

 flexible pattern, actuated, as it were, by a purposeful, co-ordinative 

 impulse. No more than leaves, blown by autumnal winds from the 

 twig and fluttering helplessly in the air, are able to assimilate for the 

 parent tree, can independent, ambulant, reactive molecules take part 

 in any organized work. It is not surprising, therefore, that the active 

 groups of the enzymes should only be capable of acting in association 

 with a carrier of a given structure. For, orderly biological processes 

 are unthinkable without presupposing structure, and it is therefore 

 out of the question that any living constituent of protoplasm could 

 consist of structureless, fluid, independently displaceable particles. It 

 is for this reason that colloid chemistry, based, as it is, upon the 

 disperse principle, has thrown so little light upon the submicroscopic 

 structure of protoplasm. For the cell certainly is not a pouch filled 

 with ultramicrons suspended in a fluid, whirling about haphazardly 

 and in confusion; it is, on the contrary, a wonderful system, the 

 intrinsic structure of which, could it but be seen, would assuredly fill 

 every observer with an enthusiasm equal to that which microscopic 

 cytomorphology inspires. 



It is true that metabolic centres (lyoenzymes, mitochondria, ery- 

 throcytes, chloroplasts) are independent of each other; but their 

 movement does not obey the law of entropy; they are actively 

 directed to the localities where their biochemical capacity is needed. 

 On the other hand, the special cytological and histological systems 

 which facilitate an appropriate production and distribution of those 

 metabolic centres (protoplasmic flow, blood capillaries, glands) must 

 have some coherent structures at their disposal. The organization of 

 these semi-solid structures is responsible for the creation of biological 

 objects of any shape or form and, therefore, is the very foundation 

 of morphogemsis. 



In the inanimate world, crystallization will at times produce 

 structures from an amorphous mass; but the structures of living 



