Mechanistic Biology 235 



ment, been a small minority of the older type of vitalists. Very 

 late in the nineteenth century they found a leader in the person of 

 Hans Driesch, and another in that of Haldane, who elevated the 

 banner of a neo-vitalism which has had a considerable number of 

 books to its credit, but few supporters. 



At the present day then the situation is in effect the complete 

 triumph of mechanistic biology. It is not alone in the field, because 

 the neo-vitalists do exist as a small minority, but the vast pre- 

 ponderance of active biological workers are mechanists. We have 

 already given four instances of the antagonism between theology 

 and mechanistic biology, and we can now add a fifth. At the 

 Modernist Conference held at Oxford in the summer of 1924 all 

 the speakers on biological subjects were professed and eminent 

 vitalists. Nothing could be more beautifully in line with the 

 traditional manner. But although it is possible to understand the 

 alacrity with which the theological mind greets vitalistic and 

 spiritualistic ideas in biology, yet it may be doubted whether, even 

 from a narrowly apologetic point of view, it was wise to nail the 

 colours of religion to the precarious mast of neo-vitalism. 



How far has mechanistic biology really triumphed .? Before 

 answering this question we must investigate the fighting power of 

 its present antagonists. 



3, A Critique of Neo-Vitalism 



The neo-vitalists, although culminating in a metaphysical 

 doctrine, began their speculations from experimental results. In 

 this respect neo-vitalism is superior to the older theories of similar 

 nature, for it does at least start with something definite even though 

 its interpretations of the observed facts may be wrong. 



Driesch, while working on certain problems in experimental 

 embryology in which he placed various obstacles in the way of the 

 normal development of embryos, was driven to the conclusion that 

 the effects he observed could never be described in terms of physics 

 and chemistry. Haldane while investigating processes going on 

 in the intact higher organism came to the same conclusion. He 

 was dealing with the delicately adjusted response which the 

 organism makes to increased oxygen-want, and he concluded as 

 the result of direct measurement that the lung epithelium must 

 actively secrete oxygen into the blood. No physico-chemical 



