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, 



