234 THE HUMAN MECHANISM 



foods, and they are largely removed from the cereal grains 

 in the attempt of the miller to produce the whitest possible 

 flour or rice, for this means the removal of the outer por- 

 tion (bran) of the grain with its vitamines. It follows that 

 " whole wheat " flour or graham flour contains these sub- 

 stances, while very white flour is deficient in them; and 

 we accordingly find that the same disease (beriberi) has 

 occurred in Newfoundland, where a community was shut 

 off during whiter from its usual food supply and white bread 

 constituted for too long a time the chief food. A similar 

 and probably identical disease has been found among people 

 living exclusively upon canned goods, the sterilization by 

 high temperatures having destroyed the vitamines. 



In the days of sailing vessels, scurvy, a disease of mal- 

 nutrition, often developed on long voyages, despite a diet 

 which contained an abundance of protein, fat, carbohydrate, 

 and salt; and it was found that this disease could be pre- 

 vented by the use of fresh limes or freshly cooked vege- 

 tables. There is little doubt that here again we are dealing 

 with a disease analogous to beriberi. 



In all the above cases it must be clearly understood that 

 there is no harmful constituent in the foods mentioned 

 canned foods, polished rice, white bread, and the like. The 

 trouble lies in the absence from the food of an essential con- 

 stituent of the diet. No harm would result, for example, 

 from a diet of canned meat, white bread, and fresh vege- 

 tables ; for the fresh vegetables would supply the necessary 

 vitamines. It is only when the diet consists almost exclu- 

 sively of foods deficient in vitamines that trouble results. 



The physiological action of these vitamines is not yet clear, 

 but we are probably not far from the truth if we regard them 

 as furnishing the body with some material indispensable for 

 carrying out the processes of chemical manufacture. Though 

 required in much smaller quantities, they are as necessary to 

 these processes as the amino-acids themselves. 



