48 



bodj" from the straig-ht than from the entire-wheat or graham flours, 

 a conclusion in accord with the results of all our former work. 



That the lower degree of digestibility of the entire-wheat and graham 

 flours was probabl}- due at least in part to a coarser granulation 

 of the particles, which consequently exposed a relatively" smaller 

 amount of surface to the action of the digesti\-e fluids, was shown by a 

 microscopical examination of the feces. The feces from both the 

 entire-wheat and the graham flours under the microscope showed a 

 larger proportion of starch particles that had not been acted upon in 

 the digestive tract than the feces from standard patent flour. The 

 micro-photographs reproduced (Pis. I-III) show the flneness of division 

 of the three sorts of flour and the starch granules in the feces obtained 

 from the standard patent, the entire-wheat, and the graham flours, 

 prepared by grinding in a mortar. 



These deductions are in accord with the results of numerous micro- 

 scopical studies of the feces from different sorts of wheat joroducts, and 

 in this connection it is interesting to refer to some of these and closely 

 related investigations. Among others mav be mentioned the work of 

 Rubner, " Pappenheim,'' Constantinidi,'' and Raudnitz. -' 



In o-eneral it mav l^e said that these investigators found that starch 

 was very thoroughly digested, but that the cells making up the outer 

 portion of the wheat berrv were little attacked by the digestive juices, 

 and hence the contents of such cells were not assimilated. Rubner 

 pointed out that the amount of undigested nitrogen increased w^ith an 

 increase in the amount of the outer portion of the grain retained in 

 flour in milling. Rathay*^ reports experimental studies, of which he 

 himself was the subject, in which the diet for a week consisted of 

 oraham bread and tea. The bread was made without leaven or veast. 

 The feces from the flfth and seventh day were examined microscop- 

 ically. He found that the grain portions which had been little masti- 

 cated were softened, but almost entirely undigested. From only a 

 few of the outer cells of the endosperm had the starch grains and the 

 proteid materials disappeared, while the greater part of these nutri- 

 ents was excreted unchanged. The general conclusion from his inves- 

 tigations was that the greater portion of the feces consisted of undi- 

 gested residues of wheat bran in the form of large flakes composed 

 of the seed coats and aleurone layer. The latter leaves the intestines 

 unchanged, probably because the thick walls of the aleurone cells pre- 

 vent the action of digestive juices upon the cell contents. So far as 

 can be learned, this investigation was the first which at all satisfac- 

 »- ■ — - 



f'Ztschr. Biol., 15 (1879), p. 115. 



i'Lehrbuch der Miillerei (1890), 3d ed., cited l)y iMoeller. 



cZtschr. Biol., 23 (1887), p. 447. 



f'Prag. med. Wchnschr., 7 (1892), pp. 1, 13. 



<" Jahresber. K. K. Realschule Sechshaus, AVien, 1874, cited by Moeller. 



