DIGESTIBILITY OF THE GKAIN SOKGHUMS. 29 



grains — they may be considered to represent the digestibility of pro- 

 tein determined directly rather than estimated. The carbohydrate 

 portion of the diet was as well assimilated as in the ordinary mixed 

 diet, indicating that the very incomplete digestibility of protein was 

 not due to faulty experimental methods. The diet proved to be 

 entirely satisfying, at least for the three-day period, for the subjects 

 reported that they were in normal physical condition throughout the 

 experiments. 



Comparing the experiments in which mush was eaten with those in 

 which sorghum gingerbread formed the major portion of the diet, it 

 was found that an average of 41 grams of protein per man per day 

 was supplied in the former and 35 grams in the latter series of ex- 

 periments. The explanation of such a small consumption of protein 

 lies in the fact that the grain sorghums contain too little protein to 

 make it feasible to obtain, say, 100 grams of protein daily on a diet of 

 this nature. The amounts of energy supplied by the mush and bread 

 diets were 3,000 and 2,850 calories, respectively, an energy value in 

 agreement with the requirements of accepted dietary standards. 



SUMMARY AND CONCLUSIONS. 



In the experiments in which hard kafir bread was eaten with milk 

 it was found that the protein of this cereal, as distinguished from that 

 of the diet as a whole, was 58 per cent digested. Possibly owing to the 

 large proportion of milk protein in the diet this value for the cereal 

 protein alone may be too high. 



In the majority of the experiments the grains under consideration 

 were eaten in the form of softer bread than that mentioned above and 

 also in the form of mushes. Considering the grain sorghums studied 

 the results show that on an average the protein of the softer dwarf 

 kafir bread, as distinguished from the protein of the diet as a whole, 

 was 51 per cent digested and that of the dwarf kafir mush 48 per cent. 

 In the case of the protein of feterita the values were 51 per cent for 

 the bread protein and 48 per cent for the mush protein. With the 

 dwarf milo the values were 40 per cent for the protein of the bread 

 and 34 per cent for that of the mush, and for the kaoliang 20 per cent 

 for the protein of the bread and 4 per cent for that of the mush. 



Fat was present in these grains in very small and relatively unim- 

 portant quantities and so no attempt was made to estimate the digesti- 

 bility of this constituent as supplied by the cereals. 



In all cases it was found that the carbohydrates of the experimental 

 rations and of the sorghums alone were very completely utilized. Con- 

 sidering the grain only, as distinguished from the ration as a whole, 

 the average value for the dwarf kafir (hard) bread was 98 per cent, 

 for softer dwarf kafir bread 96 per cent, and for dwarf kafir mush 

 96 per cent. In the case of carbohydrates supplied by feterita, the 



