232 RALPH S. LILLIE AND EARL N. JOHNSTON. 



their molecules segregate and the compounds separate out in solid 

 form, specific structure will be the inevitable result. And this 

 structure, having once arisen, will exert its own specific influence 

 upon the ensuing chemical and physical transformations in the 

 system. Any metabolism thus controlled by specific structure 

 must exhibit specific features, and if it produces further structure 

 this will also be specific, and will influence specifically the suc- 

 ceeding metabolic processes by which more structure is formed. 1 

 If we consider the growth and development of the germ in the 

 light of these general considerations, we are led irresistibly to 

 the conclusion that in any specific sequence of form-changes, 

 such as those constituting development in any organic species, 

 the character of the formative transformation proceeding at any 

 stage, as well as the special character of the terminal stage of the 

 whole sequence, the adult organism, must be determined by the 

 original structure of the system that with which the growth 

 begins. It is clear that the conditions, structural and other, 

 present when growth is begun must affect the entire succeeding 

 series of transformations. The initial factors, however, are not 

 the only ones to be considered; changes in external conditions 

 appearing at any time during the series must contribute their 

 influence; and the eventual outcome will be determined not 

 only by the initial state of the growing system and its surround- 

 ings, but also by the conditions present at any time during the 

 process of growth. This conclusion clearly implies that if the 

 surrounding conditions are kept constant, a growing system of a 

 given initial constitution will undergo a series of transformations 



1 Obviously any chemical synthesis involves a morphological synthesis, in the 

 sense of producing molecules with a definite spatial distribution of atoms and hence 

 a definite geometric form or configuration. But it is only when these molecules 

 unite or segregate (with axes parallel) to form solid structures like crystals or 

 crystal-aggregates, that the chemical synthesis becomes the condition of mor- 

 phological synthesis in the crystallographic sense; the vectorially acting intera- 

 tomic forces determine the special configuration of the molecule, and when union 

 occurs to form large aggregates the latter exhibit specific geometrical characters 

 which are determined by those of the individual molecules. The present conten- 

 tion is simply that morphological synthesis in organisms is also ultimately deter- 

 mined, in the somewhat indirect manner indicated above, by this structural specif- 

 icity of the solid material produced in metabolism. A definite internal structure is 

 thus imparted to protoplasm, and this determines a definite and specific formative 

 as well as other metabolism. 



