LUDWIG AND MODERN PHYSIOLOGY. 21 



form springs out of another. This brings him at once face 

 to face with a momentous question. He has to encounter 

 three possibilities — he may either join the camp of the 

 biological agnostics and say with du Bois-Reymond, "ignora- 

 mus et ignorabimus" or be content to work on in the hope 

 that the physical laws that underlie and explain organic 

 Evolution may sooner or later be discovered, or he may 

 seek for some hitherto hidden Law of Organism of which 

 the known facts of Ontogenesis are the expression, and 

 which, if accepted as a Law of Nature, would explain every- 

 thing. Of the three alternatives Driesch prefers the last, 

 which is equivalent to declaring himself an out and out 

 vitalist. He trusts by means of his experimental investiga- 

 tions of the Mechanics of Evolution to arrive at " elementary 

 conceptions" on which by "mathematical deduction" 1 a 

 complete theory of Evolution may be founded. 



If this anticipation could be realised, if we could con- 

 struct with the aid of those new Principia the ontogeny of 

 a single living being, the question whether such a result 

 was or was not inconsistent with the uniformity of Nature, 

 would sink into insignificance as compared with the 

 splendour of such a discovery. 



But will such a discovery ever be made ? It seems to 

 me even more improbable than that of a physical theory 

 of organic evolution. It is satisfactory to reflect that the 

 opinion we may be led to entertain on this theoretical 

 question need not affect our estimate of the value ol Dr. 

 Driesch's fruitful experimental researches. 



J. Burdon Sanderson. 



1 " Elementarvorstellungen . . . die zwar mathematische Deduktion 

 aller Erscheinungen aus sich gestatten mochten." Driesch. " Beitrage 

 zur theoretischen Morphologic" Biol. Centralblatt, vol. xii., p. 539, 1892. 



