226 DARWINISM TO-DAY. 



tifs a des destructions et des constructions d'edifices moleculaires. 

 Cette verite, toute la biologic nous la prouvera de mille manieres; il 

 vaut done mieux 1'enoncer en commengant, de maniere a ce qu'elle 

 prenne la premiere place dans Fesprit de ceux qui se livreront a 

 1'etude des etres vivants. 



"Mais une reaction chimique n'est pas quelque chose d'isole et 

 ne se produit que dans certaines conditions dont la realisation peut 

 etre liee a des particularites d'ordre physique (chaleur, electricite, 

 lumiere, etc.) ; de plus, elle s'accompagne tou jours de phenomenes 

 accessoires qui sortent egalement du domaine de la chimie (chaleur, 

 mouvement, etc.). Ceci est vrai surtout pour les reactions des 

 matieres vivantes, a cause de 1'etat tres special de ce qui represente 

 la solution de ces matieres dans 1'eau. La vie est aquatique, mais 

 les matieres vivantes ne se dissolvent pas comme du sel marin" 

 ("Traite de Biologic," pp. 43-44, 1903). 



He goes on to discuss, with keen analysis and ingenious but uncon- 

 vincing synthesis, the various primary conditions and activities of 

 life, explaining each vital phenomenon separately on a basis of 

 chemism. He even proposes a chemical notion of species. Such 

 a chemical species can of course take no primary account of form, 

 but as conditions of chemical identity will usually involve identity 

 of form, the various individuals composing a chemical species will 

 possess a similar or identical form. An author, undertaking what 

 Le Dantec undertakes, must necessarily be a bold thinker and a 

 bold writer. The present author is both. And he is nowhere unin- 

 teresting or unsuggestive, but also is he no\vhere wholly con- 

 vincing. 



The position of the neo-Vitalists is perhaps best to be taken 

 from that of Driesch, an extremely able present-day biologist, whose 



first belief was in a radical mechanical explanation of 

 Neo- Vitalism, ., .., .... 



all life phenomena, and whose brilliant experimental 



work has furnished many of the examples referred to in all text-books 

 of the modern study of the mechanics of development. But Driesch's 

 present position is an uncompromising belief in the impossibility 

 of explaining life-forms and life-functions on the basis of ever so 

 complex a combination of purely physico-chemical and mechanical 

 conditions and factors. Put positively, neo- Vitalism demands the 

 assumption of an extra-physico-chemical factor (called "psychoid," 

 according to Driesch's nomenclature), which is an attribute 

 of, or essential kind of potentiality pertaining to, organised 

 living substance, and not found in nor influencing inorganic 

 bodies. 



Biitschli has well pointed out that neo-Vitalism is really only 

 a return to the old "vital principle" belief, and that we are now, 



