422 BIOLOGICAL PHYSICS 



illustrate in his material organism, in its various phases 

 of transition, the history of the evolution of life forms, 

 vegetable and animal, and to afford the last example of the 

 "survival of the fittest," not only in his individual and 

 representative capacity as a living organism, but as an 

 embodiment as well of the production and " survival of the 

 fittest " in his various textures and organs, the result also of 

 the rigorous operation of the laws of " natural selection," 

 and the " survival of the fittest." The appraisement, there- 

 fore, of the systemic and individual values of these various 

 textures and organs must be made with a full sense of the 

 importance of each texture and organ to the maintenance 

 of the true physiological balance in the everyday activities 

 of life during its various stages. 



The stages of development, and all life is developmental, 

 comprehended within the life of the representative human 

 being, may be summarised as the embryonic, foetal, lacta- 

 tive, adolescent, adult, and senile, the first five stages, or 

 combined first stage, being evolutionary, or incremental, 

 the last, or senile, being involutionary, or decremental : all 

 which stages, however, constitute but one unbroken 

 sequence of developmental events, merging into each 

 other, and blending, so as to form a complete union. 

 Underlying and effecting this union is the foundation, 

 vegetative, structural, or organic arrangement of matter, by 

 parental or transmitted agency, in virtue of which the 

 independent existence of the incipient organism becomes 

 effected, by what may be called the operative, or formative, 

 potency of the primaryor sympathetic nerve energy inherent 

 in the " primordial germ," on the surrounding plasmic 

 elements put within its reach, and capable of immediate 

 use, so as to secure the continuity of living forms, and the 

 succession of vital evolutionary developments " generation 

 after generation." Overlying, or inter-penetrating, the 

 vegetative, or purely organic and structural arrangement of 

 this organism, is the systemic nervous system, which has 

 been evolved from and added to it, and which ultimately, 

 to a great extent dominates it by its possession and exer- 

 cise of reason and will and the thousand and one attributes, 

 mental and moral, evolved from psychological development, 

 and added to the equipment of man, to enable him in 



