PHYSIOLOGY AND THE FOOD PROBLEM 19 



a case of locking the stable door after the horse 

 was stolen. Lord Kosebery, in a sentence that has 

 stuck in our memories, said some years ago that 

 " we generally muddle through somehow," but in 

 connection with food there has been in this coimtry 

 a minimum of muddle, rationing has gone smoothly, 

 there has been but little hardship, and we are 

 through. How far physiology has been instru- 

 mental in helping to bring about this happy result, 

 I may safely leave to the judgment of others. 



APPENDIX 



THE MAIN PRINCIPLES OF DIETING 



In order to explain the word nutrition we may roughly 

 compare the body to a steam-engine. To maintain this ki 

 running order, it is necessary (1) to supply it with fuel, 

 and (2) to keep it in repair. The burning of the fuel gives 

 rise to heat and also generates the work which it is the 

 object of the engine to accomplish. Food in relation to 

 the body fulfils the same use, for it undergoes combustion 

 and thus the bodily heat is kept up, and work is rendered 

 possible. Food also achieves the second function, and 

 suppHes the material for the repair of the body's frame- 

 work which undergoes wear and tear as a result of activity. 

 Here, however, the body is superior to the engine ; in the 

 case of the latter, repair has to be accompHshed by means 

 of " spare parts," or at any rate of materials similar to 

 those origuially employed in the construction of the machine ; 

 the Uving body is able to utilise for repair certaLu materials 

 in the food which are not identical with its own substance, 

 but which are rendered identical in digestive processes. 



