ORGANISM AND MECHANISM 117 



4. Criticism of Mechanistic Descriptions of Everyday 

 Functions. 



There has not yet been given any physico-chemical descrip- 

 tion of any total vital operation. Soon after the establish- 

 ment of the doctrine of the conservation of energy, about 

 the middle of the nineteenth century, there was a remark- 

 able mechanistic boom. The impression became prevalent 

 that the citadel of life was about to be taken by storm. 

 Nerves were like wires along which electricity flowed; the 

 kidney was a group of filters; respiration was a matter of 

 the diffusion of gases; ,the passage of digested food from 

 the alimentary canal to the blood-vessels was a process of 

 osmosis; and so on. 



The inevitable reaction followed ; it was found that things 

 were not so simple as they seemed. The physico-chemical 

 descriptions leave out a good deal big residual facts which 

 seem to many to be the crucial facts. Dr. J. S. Haldane 

 writes : " The application to physiology of new physical 

 and chemical methods and discoveries, and the work of 

 generations of highly-trained investigators, have resulted 

 in a vast increase of physiological knowledge, but have shown 

 with ever-increasing clearness that physico-chemical ex- 

 planations of elementary physiological processes are as re- 

 mote as at any time in the past, and that they seem to 

 physiologists of the present time far more remote than they 

 appeared at the middle of last century" (1913, p. 47). 



In his contribution to Life and Finite Individuality 

 (1918), Dr. J. S. Haldane says (p. 13) : " I need only refer 

 to such activities as the oxidative processes in living tissues, 

 the processes of secretion and absorption, or reflex action. 

 There is a prevalent idea that the progress of chemistry, 



