44 The role of the nervous 



fulfilment of physiological equilibrium." 

 "Thus," as he goes on to say, "the reci- 

 procity of the various organs, maintained 

 throughout the divisions of physiological 

 labour, is not merely a mechanical stability, 

 it is also a mutual equilibration in functions 

 incessantly at work on chemical levels, and 

 on those levels of still higher complexity 

 which seem to rise as far beyond chemistry 

 as chemistry beyond physics^. 



But now the most striking instance of the 

 equilibration of its functions that an organ- 

 ism displays is that which brings about the 

 adjustment of internal relations to external 

 relations. In this adjustment indeed we may 

 say, as I have already urged, that life essen- 

 tially consists. But this adjustment in the 

 higher organisms, where the characteristics 



^ Sir T. Clifford Allbutt, Ency. Brit.^ vol. xviii, art. Medicine, 

 pp. 57 f. 



