30 



Hence the results for the average digestibilit^y in the different series 

 of experiments are strictly comparable. 



The tables also compare the results of the experiments reported in 

 this bulletin and those formerly reported/' It will be observed that 

 although the digestion coefficients are somewhat larger in the experi- 

 ments here reported than in those of 1899-1900, there is a general 

 similarity of results. In both series the nutrients of the bread from 

 standard patent flour are the most and those of graham the least 

 digestible, the entire-wheat flour bread being between the two. These 

 experiments are regarded as sti'ictly comparable. Considering the 

 two years' investigations as a whole, six subjects were employed and 

 eighteen separate digestion experiments were made. 



Table 16 gives the average digestil)ility of the nutrients and availa- 

 bility of the energy in the three kinds of bread as shown by the results 

 of the two series. It is believed that these figures show, with a fair 

 degree of accuracy, the comparative digestibility of the protein and 

 car1)ohydrates and availability of energy in bread made from the three 

 kinds of flour when milled from the same lot of hard spring wheat 

 and consumed under similar conditions. The results, considered as 

 a whole, show^ that the protein in the straight patent flour bread is 

 6.6 per cent more digestible than that of the graham bread, while the 

 carbohydrates are 5.6 per cent more digestible. The amount of avail- 

 able energy in the straight-flour bread is also greater by 7.5 per cent 

 than that in the graham bread. 



In Table 17 the total and digestible protein and carbohydrates and 

 total and available energy in the three diflerent kinds of flour as milled 

 are given. These values for digestible nutrients and available energy 

 were obtained by multiplying the percentage of total nutrients and 

 energy by the coefficients given in Table 17. 



Table 17. — Percentages of dif/efffihlc protein nnd earholnjdrates, and available energy in 

 entire-wheat, graham, and straight patent Jiours as milled. 



Grade of flo\ir from hard spring wheat. 



Straight patent 

 Entire wheat . , 

 Graham 



Protein (Nx5.70). 



Total. 



Per cent. 

 13.60 

 13. 72 

 14.21 



Digesti- 

 ble. 



Per Cfnt. 

 12. 01 

 11.83 

 11.77 



Carbohydrates. 



Total. 



Per cent. 

 72. 04 

 70.09 

 68. .5.5 



Digesti- 

 ble. 



Per rent. 

 70.31 

 67.43 

 62. 62 



Energy per gram. 



Total. 



Per cent. 

 3.861 

 3.877 

 3.971 



Avail- 

 able. 



Per cent. 

 3. 510 

 3.481 

 3.379 



There was a somewhat larger amount of digestible protein in the 

 straight patent flour than in either the graham or entire-wheat flour. 

 In the straight patent flour there was 70.31 per cent of digestible 

 carbohydrates, iu the entire-wheat flour 67.43 per cent, and in the 



a\J. S. Dept. Agr., Office of Experiment Stations Bui. 101, p. 33. 



