Heredity in its Relation to the Nervous System. 43 



A later theory " Creationism " suggested that the Creator is 

 perpetually creating souls, and infusing them into bodies. 

 This subjects the work of the Almighty to the will of human 

 beings. A third theory teaches that the Creator, at the 

 beginning, imparted to man a spiritual element, which should, 

 in due course, develop into a force, controlling the body, and 

 becoming fitted for a continuous existence. Thus may be 

 understood the possibility of a permanent physiological state, 

 producing or developing a permanent psychological state 

 corresponding with it. To admit psychological heredity 

 therefore follows the admission of the principle of physiological 

 heredity, and establishes the direct influence of the nervous 

 system upon mental processes. We therefore hold with 

 Spencer that Consciousness is a continuous adjustment of 

 internal with external relations, that every psychical pheno- 

 menon is inherent in some organ, and that mental and physical 

 tendencies are alike transmitted. 



Evolution, to which reference must be made, depends upon 

 external influences or environment, and influences both the 

 physical and mental characteristics. This influence can be so 

 directed as to considerably affect earlier hereditary traits, and 

 produce variation within the species. Illustrations of this fact 

 are well known. The modified theory of evolution of Monsieur 

 Naudin is that its object is to produce a definitive species, since 

 in the earliest period living creatures had a more plastic and 

 variable habit than now, and that this plastic character is an 

 evidence of design. It is however for Science yet to confirm 

 this, as well as the Darwinian theory of the variability of species. 

 No evidence can be found of the transformation of species, 

 while the weak as well as the strong find room for existence. 

 Moreover palaeontology establishes the identity of seeds, plants 

 and species with those of ages far remote, while another strong 

 objection to the transformation theory is the uniform sterility of 

 hybrids. It must also be observed that as soon as the operation 

 of environment ceases, there is a gradual return to the 

 primitive type. As Professor Drummond pointed out, choice 



