THE ETHICS OF FOOD 295 



The evidence as to the effect of the presence of branny 

 particles, even when they are very finely divided, on the 

 digestibility of bread need not be repeated. Dr. Hamill 

 supports the conclusion that bran is not only itself resistant to 

 digestion but also has the property of causing other materials 

 eaten at the same time to be less perfectly digested. He is 

 also unable to confirm the supposed advantages entire wheaten 

 bread possesses in supplying fluorine to the teeth or in pre- 

 venting dental caries. 



The case for entire-wheat bread is thus narrowed down 

 almost exclusively to experiments made by Dr. F. G. Hopkins, 

 in which it was shown that young rats ted only on white bread 

 did not thrive so well as those fed on wholemeal bread and 

 that the addition of acetic acid extracts of the wholemeal 

 bread to the white bread improved the condition of the rats 

 fed on white bread. Dr. Leonard Hill has quite recently 

 confirmed this result by feeding rats on white and on entire- 

 wheat bread ; those fed on the former were found to thrive less 

 satisfactorily but the addition of a little germ to the white bread 

 removed the discrepancy. Experiments with pigeons made at 

 Liverpool gave a similar result. Various interpretations have 

 been put on these results. Leonard Hill attributes the value 

 of the germ to the presence in it of certain amino-acids essential 

 for growth. Dr. Hopkins's results have been ascribed to a 

 deficiency of phosphorus compounds in white flour. He is 

 inclined to take a bolder step and to ascribe the value of bran 

 to the presence of unknown substances of complex nature 

 which are neither enzymes nor hormones of the nature of the 

 "Secretin" studied by Starling. Their presence enables the 

 system to make full use of the tissue-building elements of 

 the grain — milling apparently removes them to a great extent 

 from fine white flour. 



Until further information is available criticism is impossible. 

 But Dr. Hopkins's objections to white bread must disappear 

 at once when it is consumed with natural food, such as milk 

 or meat, which contain the mysterious bodies unchanged ; his 

 preference for standard bread in a mixed diet is therefore of 

 academic rather than of economic importance. 



Dr. Hamill adds some useful evidence by summarising recent 

 work on Beri-beri, a disease caused by a diet consisting of de- 

 corticated rice alone such as is sometimes customary in the East. 



