of the University of Pennsylvania. 65 



presence of a bulky intestinal contents of a mechan- 

 ically stimulating nature, and also by the nutritive 

 salts which were present in this bread in larger 

 amounts than in others. On the other hand, at the 

 end of the thirty-two days the animals had notably 

 increased in size; the food given was then barely 

 sufficient for the needs of the economy, and any 

 conditions impeding its complete digestion and ab- 

 sorption produced a notable effect upon the rate of 

 growth of these young animals. 



It must be borne in mind that these experiments 

 relate only to the value of the different breads when 

 taken alone to the exclusion of other foods. The 

 experiments of Rubner before cited leave no doubt 

 that a white bread contains more assimilable nutri- 

 ment than does one made from the whole wheat, 

 but this does not render it a desirable food-stuff for 

 exclusive use. On the contrary, a weaned, but still 

 quite young omnivorous mammal thrives better 

 upon an exclusive diet of bran bread than on white, 

 and, presumably, because the earthy and alkaline 

 salts are present in greater abundance in the former, 

 and, also, because the indigestible constituents tend 

 to give to the intestinal contents that bulk and con- 

 sistence which are essential to the hygiene of the 



digestive tract. But, as has been shown by Edward 

 6* 



