36 PHYSIOLOGY AND NATIONAL NEEDS 



Except for those who view nutrition too exclusively 

 from the standpoint of energy supply, there is no 

 reason for surprise in this circumstance. 



What should be clearly grasped is the fact that 

 without the minute quantities of accessory sub- 

 stances, perfectly wholesome and, indeed, from the 

 standpoint of their own functions, absolutely neces- 

 sary foodstufis are not, in any complete and proper 

 sense, utilised at all. They are absorbed and the 

 energy contained in them is liberated in the body, 

 but the co-ordination of metabolism is absent, and 

 neither material nor energy is employed aright. 

 When the minute addendum is supplied these very 

 same food-stuffs become perfectly available as a 

 whole. We may think of such facts in terms of a 

 very rough analogy. If a house is to be built it is 

 bricks and wood which bulk largely in the necessary 

 supply. The bulk of necessary nails is out of all 

 proportion small, and even that of the mortar is 

 relatively small ; but it would be impossible to 

 erect a normal house without at least a minimal 

 supply of nails and mortar. Without them the rest 

 of the building materials would, from the stand- 

 point of a future tenant, be useless. From the facts 

 just dealt with and from those brought to light from 

 the study of beriberi the conception of vitamines 

 emerges. The analogy just used may indeed be 

 wrong. Vitamines may not be concerned with the 

 structure of the tissues, but rather as stimulants 



