40 GERMINAL SELECTION. 



germinal cells. Roux himself spoke of the struggle 

 of the molecules, by which he presumably understood 

 the smallest ultimate units of vital phenomena ele- 

 ments which De Vries designated pangenes, Wiesner 

 plasomes, and I biophores, after Briicke's ingenious 

 conception 1 of these invisible entities had been almost 

 totally forgotten, or at least had lain unnoticed for 

 thirty years. No struggle, as that is understood in 

 the theory of selection, could take place between real 



1 Delage, in La structure du protoplasma el les theories sur 

 Vheredite, etc., Paris, 1895, is mistaken in attributing to Her- 

 bert Spencer the merit of having first pointed out the neces- 

 sity of the assumption of biological units ranking between the 

 molecule and the cell. Briicke set forth this idea three 

 years previously to Spencer and established it exhaustively 

 in a paper which in Germany at least is famous ("Elemen- 

 tarorganismen," Wiener Sitzungsberichte, October 10, 1861, 

 Vol. XLIV., II., p. 381). Spencer's Principles of Biology ap- 

 peared between 1864 and 1868 ; consequently there can be 

 no dispute touching the priority of the idea. Strangely 

 enough Delage cites Briicke's essay in the Bibliographical 

 Index at the end of his book correctly, although Brucke's 

 name and views are nowhere mentioned in the book itself. 

 It is to be observed, however, that the elementary organisms 

 of Briicke are not merely the precursors of Spencer's "phys- 

 iological units," but repose on much firmer foundations than 

 the latter, which, as Delage himself remarks, are at bottom 

 nothing more than magnified molecules and not combinations 

 of different molecules of such character as to produce neces- 

 sarily phenomena of life. He aptly remarks on this point: 

 "the physiological units of Spencer are only chemical mole- 

 cules of greater complexity than the rest, and as he defines 

 them they would be regarded as such by every chemist. He 

 attributes to them no property essentially different from 

 those of chemical molecules." Assimilation, growth, propa- 

 gation, in short the attributes of life, are not attributed by- 

 Spencer to his units, while Briicke by his very designation 

 "elementary organisms" expresses the idea of "ultimate living 



