80 Vitality and rgamzation of Protoplasm. 



though proportionately reduced in size^, resemble in all essential struc- 

 tural details the normal embryo. 



It has been here demonstrated that the organic form in all its struc- 

 tural details is the visible expression of the specific chemical constitution 

 of the living substance composing it. Consequently, in the intricacies 

 of this chemical constitution has to be sought the explanation of the 

 phenomena under consideration. The potency of a chemical fragment 

 to develop into a full-sized embryo, when supplied with sufficient com- 

 plemental material; or, failing this supply, the potency to transform its 

 own substance into a proportionately-sized embrj^o; this potency of 

 fragments to reconstruct the complete typical embryo out of whatever 

 amount of formative material is available, seems to indicate that each 

 definite link in the chemical structure underlying the specific form of 

 an organism is a subordinate formative division, which has power sep- 

 arately to increase in bulk or grow to adult stature in proportion as it 

 is supplied with nutrition or complemental material. And this suppo- 

 sition seems to be corroborated by the mosaic-like morphological divi- 

 sions, which make their appearance during ontogenetic evolution. And 

 corroborated also by the separate regenerative power of such mosaic-like 

 divisions, or structural provinces. 



In normal ontogeny the blastomeres of each stage of segmentation 

 have to be regarded as the merging into morphological visibility of 

 latent dispositions in the chemical structure of the germ-plasms during 

 its process of gradual reintegration. Each blastomere contains then 

 potentially all structures to be eventually evolved from it. Each suc- 

 cessive segmental division or segregation curtails and distributes thus 

 the potential areas of reproduction, confining them to specific portions 

 of the evolving substance. And when, at last, such formative morpho- 

 logical subdivisons have reached their climax, and have conjointly re- 

 produced the adult organism; then it is found that such morphological 

 areas may still possess more or less separate reproductive potentiality, 

 as evidenced by manifold phenomena of regeneration. And the less 

 highly differentiated such morphological areas have come to be, the more 

 reproductive potentiality do they generally retain. 



In this light it becomes irrefragably certain that in ''multicellular" 

 organisms the divers ''cells" that compose their specific tissues are as 

 direct derivatives of progi-essive segmentation, not autonomous lineal 

 descendants of an elementary mother-cell; but very obviously definite 

 morphological subdivisions, arising during progressive ontogenetic evo- 

 lution as complemental constituents of a predetermined whole. And as 

 such they may likewise retain reproductive potentiality of their own; 

 may undergo mitotic division, or may even as epithelial "cells" repro- 

 duce highly complex structures. 



That which is visibly revealed as vital organization in all its minutely 

 differentiated and functionally interdependent structures proves to be 

 the morphological manifestation of what our scientific experience teaches 

 us to regard as specific chemical and specific vital potencies. 



