270 Influence of environment on animals 



succeeded in this, but the writer wishes to apologise to these authors 

 for his inability to convince himself of the validity of their claims 

 at the present moment. He thinks that only continued breeding 

 of these apparent mutants through several generations can afford 

 convincing evidence that we are here dealing with mutants rather 

 than Avith merely pathological variations. 



"What was said in regard to the production of new species by 

 physico-chemical means may be repeated with still more justification 

 in regard to the second problem of transformation, namely the 

 making of living from inanimate matter. The purely morphological 

 imitations of bacteria or cells which physicists have now and then 

 proclaimed as artificially produced living beings ; or the plays on 

 words by which, e.g. the regeneration of broken crystals and the 

 regeneration of lost limbs by a crustacean M^ere declared identical, 

 will not appeal to the biologist. We know that growth and develop- 

 ment in animals and plants are determined by definite although 

 complicated series of catenary chemical reactions, which result in 

 the synthesis of a definite compound or group of compounds, namely, 

 nuclcins. 



The nucleins have the peculiarity of acting as ferments or 

 enzymes for their own synthesis. Thus a given type of nucleus will 

 continue to synthesise other nuclein of its own kind. This determines 

 the continuity of a species ; since each species has, probablj'^, its own 

 specific nuclein or nuclear material. But it also shows us that 

 Avhoever claims to have succeeded in making living matter from 

 inanimate will have to prove that he has succeeded in producing 

 nuclein material which acts as a ferment for its own synthesis and 

 thus reproduces itself Nobody has thus far succeeded in this, 

 although nothing Avarrants us in taking it for granted that this task 

 is beyond the power of science. 



