26 



preparation, is slightly the better digested. The carbohydrates of corn- 

 meal were very completely digested, and this food fully sustained 

 its reputation as a good energy producer. Apparently the malting or pre- 

 digesting to which Orange Meat, Force, and Norka have been submitted 

 in the preparation process has not improved the completeness of their 

 absorption. Even the carbohydrates, which would be the most affected 

 by the previous treatment, are not so completely digested as in the other 

 foods. Of these three foods, or, in fact, of all the foods experimented 

 with, Force has given the poorest results. It will be remembered that in 

 so far as the efficiency of the malting and cooking process can be measured 

 by the solubility of the organic matter of Force, a wheat product, it was 

 not equal to that produced by cooking wheat farinas for twenty minutes ; 

 and it is quite possible that this comparatively poor preparation has 

 affected its digestibility. 



There is one important factor, namely, ease of digestion, that has 

 not been taken into consideration in the above discussion. All work done 

 in the body must result in the expenditure of a certain amount of energy, 

 and, consequently, while two foods may be equally completely digested, 

 one may be more easily acted upon by the digestive juices, and, as a 

 result, a greater amount of the total energy would be left for the produc- 

 tion of new material or for work. We have no way of measuring the 

 energy expended in doing the work of digestion, and, therefore, cannot 

 give figures on this point ; but it seems fair to assume that two foods 

 prepared from the same kind of grain and cooked to the same extent, 

 and of practically the same composition, will require an equal amount of 

 energy to carry out the work of digestion. Thus, two samples of rolled 

 oats prepared in the same manner and cooked for the same length of time 

 would probably require an equal amount of energy in digestion. If, 

 however, the preparation of the foods for consumption had increased the 

 solubility of the nutrients of one food more than the other, it would 

 probably be more easily digested. Thus Norka contains, according to 

 our determination, 28 per cent, of soluble matter, while rolled oats, after 

 cooking twenty minutes, contains nearly 15 per cent. But when the 

 cooking process was continued for five hours, the solubility of the oat- 

 meal was equal to that of Norka, and probably the energy of digestion 

 would be about equal. It would be equally correct to argue that as 

 Force contained only 17 per cent, of soluble material and wheat farinas 

 cooked twenty minutes 27 per cent., the former would require a greater 

 expenditure of energy to digest it than the latter. If this be true, then 

 Force not only is less completely digested, as shown in the above table, 

 but it also required the expenditure of more energy to do the work of 

 digestion and thus the nutritive value of the food would be still further 

 decreased. 



But while we cannot measure the ease with which the digestion of 

 foods is accomplished, we can, to some extent, estimate the rapidity of 



