96 THE POPULAR SCIENCE MONTHLY 



IV 



The problem of vitalism need be very briefly examined. Vitalism, 

 if it means anything in biology, interprets life in terms of forces or 

 agencies or processes that are not found in inorganic nature. Accord- 

 ing to this definition, Aristotle was a vitalist when he conceived the 

 development of the germ to be guided by the entelechies that determined 

 specific and individual form in organisms. Wolff was a vitalist when 

 he accounted for the differentiation of a homogeneous germ by the aid 

 of a vis essentialis. Vital forces have long since lost their grip. They 

 began to weaken when Wohler, in 1828, produced in the laboratory the 

 compound urea, till then supposed to be formed only in the bodies of 

 organisms. They broke into full retreat under the fire of calorimetric 

 researches of the last century which demonstrated that oxidation was 

 oxidation, whether it took place within or without the body, and that 

 vital heat was as surely due to chemical reaction as the heat generated 

 by the reaction between sulphuric acid and zinc. 



So Wolff's vitalism is dead. The Aristotelian vitalism, however, has 

 a representative at the present day in the neo-vitalism of Driesch. The 

 Aristotelian entelechy has been revamped and applied to the unex- 

 plained residuum that has escaped Driesch's experimental analysis. It 

 is interesting that Driesch was a metaphysician first, an experimental 

 biologist second; and that after about fifteen years of unusual activity 

 in this second role, he returned to his first love. In these fifteen years 

 he developed what he has called three proofs of vitalism. But he has 

 not succeeded in persuading many biologists to accept his criteria of 

 demonstration. It is difficult to take seriously his conception of en- 

 telechy, a non-substantial, non-energetic principle which yet is com- 

 petent to control the developmental energies of the organism. It is but 

 another final cause, an ultimate term in the analysis of the activities 

 of organisms. And it has weakened Driesch's interest in biological 

 research just as the formulation of final explanations has led to stagna- 

 tion wherever we have met them along the line of biological inquiry. 



In contrast with Driesch, there is a large and eager group of experi- 

 mental biologists who unite in deprecating his interest in entelechies 

 and, undaunted by its enormous complexity, in investigating the organic 

 mechanism in the hope of reducing more of it than he was able, to 

 terms of physics and chemistry. How far they may go is not, from the 

 standpoint of modern biology, a pertinent question. How they may 

 keep moving is more to the point. To this end the Drieschian entelechy 

 offers not the slightest suggestion of encouragement. 



V 



Three of the four problems to which attention was invited at the 

 beginning of this paper have now been considered. If I have succeeded 



