8 THE MECHANISTIC THEORY OF LIFE 



was formerly suspected. This, however, 

 cannot legitimately be used as an argument 

 against the mechanistic theory : for the pro 

 gress which has been made by applying 

 chemical methods is solid progress, to which 

 there has been no set-back, though the goal 

 has turned out to be further away than 

 appeared to be the case about the middle 

 of last century, at the time of the general 

 movement among physiologists towards the 

 mechanistic theory. It is, perhaps, on the 

 chemical side that physiology has made its 

 most striking advances in recent times; but 

 on the physical side the advance has also 

 been continuous. 



We may now turn to some of the argu 

 ments which have been used in favour of a 

 non-mechanistic interpretation of biological 

 facts. Perhaps the most striking fact with 

 regard to physiological phenomena is the 

 evidence they present of activity co-ordinated 

 in such a manner as to conduce towards the 

 survival of either the individual or the species. 

 Co-ordination of a similar striking kind is not 

 found anywhere outside the organic world ; 

 and the mere existence of this co-ordination 



