THE SPECIFIC CHARACTERISTICS OF VITALITY 549 



its own substance. It takes up to itself only material which 

 is already similar to itself ; this is not assimilation, it is merely 

 incorporation. 



Writers of a materialistic bias have, however, striven to 

 regard such growth of crystals as not essentially differing from 

 protoplasmic growth. Except that matter is taken up from 

 outside in both cases, there is no similarity between the two 

 processes at all. Growth of bioplasm, which includes and is 

 the outcome of the incorporation of the dissimilar, the essence 

 of the metabolic phenomena characteristic of living matter, is 

 something sui generis. 



The term " growth," strictly speaking, can be applied only 

 to metabolism in the immature or convalescent organism. 

 The healthy adult is not " growing " in this sense ; when of 

 constant weight he is adding neither to his stature nor his 

 girth, and yet he is assimilating as truly as ever he did. Put 

 more technically : in the adult of stationary weight, anabolism 

 is quantitatively equal to katabolism, whereas in the truly 

 growing organism anabolism is prevailing over katabolism, and 

 reversely in the wasting of an organism or in senile decay, 

 katabolism is prevailing over anabolism. The crystal in its 

 solution offers no analogies with the adult or the senile states 

 — but these are of the very essence of the life of an organism. 

 The crystal, when not incorporating molecules exactly similar 

 to itself, is not in any sense active ; but an organism at all 

 stages of its life-history is active — unless indeed it is in the 

 state of latent life. 



The fact, of course, familiar to every beginner in biology 

 is that the crystal is only incorporating and not excreting 

 anything, whereas the living matter is always excreting as well 

 as assimilating. This one-sided metabolism — if it can be 

 dignified with that term — is indeed characteristic of the crystal, 

 but it is at no time characteristic of the living organism. The 

 organism, whether truly growing or only in metabolic equili- 

 brium, is constantly taking up material to replace effete 

 material, is replenishing because it has previously displenished 

 itself or cast off material. The resemblance between a so- 

 called "growing" crystal and a growing organism is verily of 

 the most superficial kind. 



It is true that a living organism resembles a wave — the 

 form persisting, the matter changing — but that does not 



36 



