Mechanistic Biology 239 



his biological and psychological natures. When we regard him 

 simply as a coloured object or a certain weight, we still further 

 abstract from reality, as in the impersonal " Hommes 40. Che- 

 vaux 16 " written on French railway wagons. To abstract 

 nothing from reality we must consider him as nothing short of a 

 personality. 



To do justice to Haldane's views is difficult, for his arguments 

 are dangerous vehicles, and in following him it is necessary to get 

 off just at the right place. Enough has been said, however, to give 

 an idea of the neo-vitalist position, a standpoint adopted by Arthur 

 Thomson and E. S. Russell, as well as Driesch and Haldane, 

 though with individual modifications. Their views have found 

 very little acceptance among zoological and physiological workers 

 and, naturally, none at all among biochemists and biophysicists. 



In the criticism of the neo-vitalist position, the first -thing that 

 appears is the insufficiency of the basis which led the neo-vitalists 

 to take up their present attitude. It almost looks, from a psycho- 

 logical point of view, as if, unable to bear the thought of the possi- 

 bility that biology is really applied physics and chemistry, they had 

 laboriously striven by philosophical discussion to avoid coming to 

 that conclusion. 



At any rate it is quite a mistake to suppose that their opinions 

 are in any way new. It is interesting to compare Stahl's writings 

 on the anima sensitiva in his " Theoria Medica " of 1 708 with the 

 description of the entelechy in Driesch. The more the two are 

 compared the more remarkable the resemblance becomes ; each is 

 conceived of as a non-material force informing the tissues of the 

 organism and controlling in a subtle manner all the different 

 chemical processes which are going on in them. It could certainly 

 be argued that there must be something in the idea if two biologists 

 such as Stahl and Driesch, separated by two centuries, could come 

 to a very similar conclusion. But to say that would be to neglect 

 the enormous advances in biological chemistry and physics which 

 had been made between 1708 and 1908, so that whatever praise 

 we allot to Stahl for his theory we must allot much less to 

 Driesch for his, since he put forward an essentially similar con- 

 ception at a time when it was far less likely Indeed, all the 

 speculations of the neo-vitalists have been preceded by those of the 

 iatro-chemists, with this only difference, that the iatro-chemists 

 were nearer the days of daemonology than the neo-vitalists. 



