vi PREFACE 



which may well prove to be of supreme importance 

 for the welfare, and, it may be, the advancement of 

 the human race. 



If there is a peaceful future for aviation, as so many 

 suppose, the physical and mental tests devised for the 

 selection of war pilots in Colonel Flack's lecture must 

 be the foundation on which we shall build in organ- 

 izing the personnel of a great new industry of com- 

 munications. 



To mention but one more case. In the field of 

 peaceful industry what results are likely to be of 

 greater utility than the " efficiency and fatigue" data 

 drawn from the munition factories? And what con- 

 ditions could have been more favourable for their 

 collection than those provided where vast quantities 

 of shells, cartridges, and other engines of war were 

 being produced? 



The collection as a whole, incomplete as it neces- 

 sarily is, seems to show that much of the "war work" 

 of biology will have its peaceful application. The 

 " sword" which the biologist wields in war becomes, 

 automatically, a "ploughshare" with the dawn of 

 peace. 



F. W. O. 



