THE WONDER OF LIFE 627 



another's hands, how are they co-ordinated in a harmoni- 

 ous result, how are they adjustable to changeful external 

 conditions ? Even a complete ledger of the osmotic and 

 capillary processes, the oxidations and reductions, the 

 solutions and fermentations, would not furnish the kind of 

 description the biologist wants. 



We must bear in mind the extraordinary complexity 

 of the problem of the everyday hfe of any common animal. 

 For what is a creature but a huge army with battahons 

 which we call organs, brigades which we call systems ? 

 It advances insurgently from day to day always into new 

 territory — often inhospitable or actively unfriendly ; it 

 holds itself together, it forages, it makes good its own losses, 

 it even recruits itself, it pitches a camp and strikes it again, 

 it goes into winter-quarters, it retreats, it recovers itself, 

 it has a forced march, it conquers. What the biologist 

 wishes is a description of the organism's daily march which 

 will not ignore the reahty of the tactics — ^the intra-organis- 

 mal tactics. 



In addressing the Physiological Section of the British 

 Association in 1909, Professor B. H. Starhng said : — 



' In his study of Hving beings the physiologist has one 

 guiding principle which plays but httle part in the sciences 

 of the chemist and physicist, namely, the principle; of 

 adaptation. Adaptation or purposiveness is the leading 

 characteristic of every one of the functions to which we 

 devote inJ our textbooks the chapters dealing with assimila- 

 tion, respiration, movement, growth, reproduction, and 

 even death itself '. 



Now adaptation or purposiveness requires a historical 

 explanation ; it is a supra-mechanical concept. It is true 



