2 4 o BIOLOGICAL PHYSICS 



member of the healing art, and the intelligent layman, 

 who takes pains fully to acquaint himself with the nature 

 of the information it conveys. The mucosa of the whole 

 buccal (Fig. 100) cavity, with the structures which it 

 covers, is, more or less, active, in the functional work of 

 cerebral excretion, more or less, modified lines of exit, 

 continuing to maintain that excretional function, first 

 established by the direct union of the buccal and 

 cerebral, cavities, at the antero-central aspect of the 

 nascent cerebrum. 



These local structural lines of exit may be likened to 

 those of a sponge, which, on being squeezed, by every 

 act of deglutition, conscious, or unconscious, and every 

 movement of the tongue, empty themselves into the 

 mouth, relieving the outflow vasculature, and, secondarily, 

 assisting in the work of digestion, and alimentation, thus 

 contributing to the double function of secretion, and 

 excretion, and aiding in the economy of the great nutri- 

 tional activities of the body at the same time. 



Such are a few of the steps of the organic developmental 

 evolution of the human organism, and they may suffice to 

 show the absolute continuity of the process, the constant 

 adaptation of means to ends, the survival of the fittest, 

 in texture and organ, and the culmination in attainable 

 perfection, of both structure and function, but with the 

 inexorable final result of material, textural involution, 

 decay and death. 



Contemporarily with this process of organic develop- 

 mental evolution, moreover, a higher, or psycho- dynamic, 

 evolution is being effected, whereby the growth of the, 

 ego, inner man, or intellectual being, is secured, in har- 

 mony with the various stages of advancement characterising 

 that organic developmental evolution. 



The rudiments of psychic being begin to manifest 

 themselves in very early infancy, rapidly increase as the 

 period of lactation advances, continue active during the 

 period of childhood, gather strength during the "acquire- 

 ment of education " and merge into full intellectual 

 development during the succeeding years, increasing, as 

 " knowledge of the world " becomes added to the mental 

 furniture, 



