16 PHYSIOLOGY AND NATIONAL NEEDS 



lias been given in the food. What the glycerine is 

 made from is a chemical puzzle, though, perhaps, 

 those who say that it originates from sugar are not 

 far wrong. We may congratulate ourselves upon 

 British enterprise which has rendered the supply 

 of margarine now so large that coupon restrictions 

 were soon abolished, and modern margarines are 

 in many cases made so attractive and so palatable 

 that the old prejudices against this butter substi- 

 tute have very nearly disappeared. 



In real butter there is present another of those 

 materials called vitamines essential for health and 

 more particularly for the growth of young animals. 

 We do not know its chemical composition but we 

 do know that it is present in this as in most other 

 forms of animal fat ; but it is absent from vegetable 

 fats, and as vegetable fats are so largely used ^ now 

 in margarine manufacture care will have to be taken 

 in the future, by legislative enactment or otherwise, 

 that margarines contain a sufficient admixture of 

 fats of animal origin ; there will be danger of 

 '' deficiency disease " and stunted growth unless 

 such precautions are taken. 



This vitamine though absent from vegetable oils 

 is really of vegetable origin, and during plant 

 growth is found in the green parts. The animal 

 body can make glycerine but is not able to make 



^ Previous to use oils are " hardened " by a process known as 

 hydrogenation ; this is carried out at high temperatures which would 

 destroy any vitamine if it were originally present. 



