FUNCTION AND ENVIRONMENT 203 



There are two sides to all doctrines of vital- 

 ism a negative side which argues towards 

 the impossibility of holding to the purely 

 mechanistic interpretation, and a positive 

 side which attempts some further elucidation 

 of the life-mystery. 



As an outspoken statement by a competent 

 physiologist and physician of the vitalist 

 position, on its critical side, we may take 

 Dr. Haldane's recent British Association 

 address (Dublin, 1908). "In Physiology, 

 and Biology generally, we are dealing with 

 phenomena which, so far as our present 

 knowledge goes, not only differ in com- 

 plexity, but differ in kind from physical and 

 chemical phenomena; and the fundamental 

 working hypothesis of Physiology must differ 

 correspondingly from those of Physics and 

 Chemistry." . . . "The physico-chemical 

 theory of life has not worked in the past and 

 never can work. As soon as we pass beyond 

 the most superficial details of physiological 

 activity it becomes unsatisfactory; and it 

 breaks down completely when applied to 

 fundamental physiological problems, such as 

 that of reproduction." 



THEORIES OF VITALISM. A constructive 

 and comprehensive endeavour to formulate 

 a doctrine of vitalism is that of Dr. Hans 

 Driesch's recent Aberdeen Gifford Lectures, 



