Introductory 19 



mechanics as a system of thinking on biological subjects is 

 its effort to deal with organisms in terais of parts of or- 

 ganisms; otherwise expressed, that it is a systematic effort 

 to avoid recognizing the organism in itself as a true objec- 

 tive entity. Because of the persistence, industry, enthusiasm, 

 and withal great ability shown by Roux in applying ele- 

 mentalism to many aspects of living beings, his title to 

 chieftainship of what the Germans call "Zersplitterungs- 

 theorien" can hardly be disputed, at least so far as this 

 present era is concerned. 



We shall have to deal with both the practical and theoret- 

 ical sides of the Rouxian school under several other captions, 

 but this much may be said now. Developmental mechanics 

 has one great merit over any other form that elementalism 

 has taken at any time in the history of biology, in that it 

 gives ungrudging recognition to many orders of constituent 

 parts of plants and animals. Organs and tissues of various 

 grades and classes — cells, nuclei, chromosomes — in short all 

 the parts of the organism, are accepted as real existences, 

 only the organism itself being ruled out. In this respect 

 Roux's elementalism is far more genuinely biological and 

 scientific than is, for example, the purely chemical form of 

 elementalism, that form which virtually denies reality not 

 only to the organism as a whole but to all of its parts except 

 what in its most general mode of expression it calls the 

 "living substance." 



Superior in some respects as the conceptions underlying 

 developmental mechanics are to those underlying purely 

 chemical elementalism, far more superior are they to that 

 form of elementalism the citadel of whose biological faith 

 is constructed from deepest foundation to highest pinnacle 

 of "hypothetical living units," of which Spencer's physio- 

 logical units, Darwin's pangens, and Weismann's determi- 

 nants are the most famous examples. The reason why 

 strictly metajjhysical conceptions of this type all prove to 



