154 



BIOLOGICAL LECTURES. 



alike constant and always alike operant under like conditions, 

 i.e., to reduce organic formation to such modi operandi as are 

 constant, albeit in themselves not understood. 



Every "complex component" thus represents merely the 

 effect, the resultant of inappreciable individual effects. From 

 such complex components result most of the formative processes 

 which we perceive; it is our task, therefore, to analyze the 

 chaos of internal operations into the least possible number of 

 such modi operandi. 



In the first place the elementary cell-functions are such 

 "COMPLEX COMPONENTS": assimilation, dissimilation (katabo- 

 lism) the self-movement of the cell in general, the self-division 

 of the cell as a definite coordination of self -movements ; to these 

 we may add the typical formal s elf -cons tmctivity and the quali- 

 tative self-differentiation of the cell as still more highly compli- 

 cated effects. 



On the other hand, the growth in mass of cells probably re- 

 presents only the resultants of simultaneously occurring pro- 

 cesses of assimilation and dissimilation ; and the same may 

 hold good with reference to external pressure when the cell 

 decreases in mass. Local growth, however, besides depending 

 on a growth in mass of the cells of a given area may also 

 depend on the immigration of cells, and hence on other com- 

 plex components, such as chemiotropism and cytotropism (3). 

 On the other hand, exclusively " dimensional growth " (4) of an 

 area may depend on the active metamorphosis of cells. Further 

 complex components which also determine the direction of 

 movements in unicellular or multicellular organisms are galvano-, 

 helio-, hydro-, and thigmotropism. 



The directive effect of the u form " of the cleavage-cell prior 

 to its histological differentiation on the position of the nuclear 

 spindle, viz., the adjusting of the spindle to coincide with the 

 longest axis that can be drawn through the center of mass of 

 the protoplasm (5); the trophic effect of functional stimuli (to 

 which all the extraordinarily diverse phenomena of functional 

 adaptation are reducible) (6) ; the trophic effect of ganglion cells 

 on their nerve-fibres and corresponding end-organs all these 

 are further complex components which are already established, 



