26 BIOLOGICAL PROBLEMS 



favour of it or otherwise. As this type of bread must 

 continue to be the national supply for some time to 

 come, and, as its use may possibly outlast the war, 

 there is some excuse for considering rather fully such 

 facts as are known to bear upon the relative food 

 value of breads made from various types of flour. 



Although natural taste and preference doubtless 

 played their part in so firmly establishing the use of 

 a white porous loaf in this country, circumstances have 

 done a good deal towards the creation of the taste, 

 and historically events have acted and reacted upon 

 each other in an interesting way to determine the 

 nature of our bread-supply in successive periods. 



If Britain could have continued to grow wheat 

 enough to feed her population we might still be eating 

 the somewhat dark-coloured nutty-flavoured bread of 

 the stone-mill period; while windmills and watermills 

 would still be familiar to the countryside. But so far 

 back as when the Germans were last on French soil 

 we grew but half the wheat we ate, and when they 

 struck again we were growing but a fifth. 



Now, while home-grown wheats well suited the 

 miller who used to grind them between stones, the 

 imported wheats gave him trouble. When the latter 

 came to preponderate in the market a revolution in 

 the milling industry occurred, and the use of steel 

 rollers in place of stones became almost universal. 

 Once roller milling was established it was easy to 

 make very white flour from the foreign wheats, and, 

 these being for the most part " strong' wheats in a 

 sense to be presently discussed, our bread became 

 not only whiter but lighter and more porous than in 

 the days of the stone mill. It is worth while perhaps 

 to go more fully into the details of these changes. 



The old-fashioned stone mill had in its way reached 

 great perfection as an instrument. Great care was 



