124 THE CONTROL OF LIFE 



ment of life. The healthy man must be able to adjust 

 himself to circumstances without losing his foothold ; 

 he must be able to respond to stormy as well as sunny 

 days ; he must have a fair measure of resisting power 

 to the invasions of disease-germs and to other deteriora- 

 tive influences. 



Yet health, we must admit, is a relative quality, and 

 our attainment of it is not usually more than approxi- 

 mate. (1) One reason for this is that many of us start 

 with some hereditary handicap, sometimes trivial, 

 sometimes serious. All that we can do is to recognise 

 and understand this handicap, and to establish by 

 wholesome surroundings and habits a set of counter- 

 actives. (2) But there is a larger reason — ^namely, that 

 Man's bodily organisation does not in its evolution 

 keep pace with his habits and surroundings. Thus it is 

 that some old-established parts of our structures, which 

 have done duty admirably for ages, do not suit quite so 

 well in the artificial conditions of modern life. They lag 

 behind and give rise to what are called bodily ' dis- 

 harmonies.' 



For an understanding of bodily disharmonies we owe 

 much to the insight of the Russian biologist, MetchnikofE 

 {d. 1916), though he tended, like many other discoverers, 

 to overstrain his bow. The reduction of the snout 

 region and the enlargement of the forehead became 

 possible among our arboreal ancestors by the emancipa- 

 tion of the arm from being an organ of support for the 

 body, as it is in quadrupeds, and by the promotion of 

 the hand — the free hand — to the office of testing things, 



