Another phase of this matter that promises to develop in the near future as a result of the vitamine hypothesis is a reform in food manufacture. There has been a strong tendency during the past two decades to "purify" food products. The genesis of this tendency is to be found in a highly laudable ambition to force the manufacturer to eliminate impurities and adulterations and provide clean, wholesome, sanitary food. Unfortunately in attempting to meet this demand on the part of the public, the food manufacturer has sometimes neglected to seek advice from the nutrition expert and the latter has failed to appreciate the need of advice. The net result has been to discover that Nature is often a better chemist than man and has a much better knowledge of what man needs in his diet than the chemist. The chemist employed by the manufacturer has, as a result, gone to such a limit in his development of purification methods as to often eliminate the essential nutrients and the result has been foods that will stand analysis for pure nutrients, but which will not stand Nature's analysis for dietary efficiency. As a secondary result of this tendency we have acquired habits that in many cases must either be broken or must have grafted on to them other habits which shall remedy the defective ones. Take the milling of wheat as an example. Nature put into the wheat grain most of the elements needed by man and in the early days he was content to grind up the whole grain and find it palatable. The craze for purity as expressed by color has gradually replaced this whole meal wheat with a beautiful white product that is largely pure starch with a few of the proteins retained. And the principal protein retained lacks one of the greatest essentials for growth while the vitamines have all been practically eliminated with the grain germ. Intelligence tells us then that if, having formed the habit, we will persist in our appetite for white flour we must see to it that the protein deficiency of the latter and its lack of vitamines is compensated for by supplementing the diet with the food-stuffs in which these are rich. We may in other words retain our bad habits in taste if we will graft on to them the attention to the eliminated factors and their substitution in other form. In general then, the adult needs to review his feeding habits and analyze them in the light of our new knowledge. For this purpose the tables of Chapter IV supply data useful so far as vitamines are concerned, but it will be perhaps worth while to repeat here some of this data in more generalized form. _a. Sources of the "A" vitamine_