238 EXPERIMENT STATION EECORD. 



As a rule tho porceiitaiics of pentosans digested by different slieep 

 agree (juite closely. Comparison with the other ingredients of the 

 different feeding stnifs shows that in G out of cases the pentosans, 

 were practically as digestible as any other group of ingredients. 



"With the more concentrated foods the pentosans areas dig-estiblo as either the 

 fat, protein, or extract matter. The results make clear that association has a great 

 deal to do with digestibility. In the hays, corn cobs, and brewers' grain, where the 

 woody substance (lignin) is preseut to a considerable extent, the digestibility of the 

 pentosans is noticeably less than when the iucrusting substance is absent. WhetAier 

 or not the pentosans are chemically united to the iucrusting substance is not known, 

 but it is not at all improbable. It is certainly clear that the iucrusting substances 

 perceptildy interfere with the digestibility of the xylau or araban. This has also 

 been proved to be the case with cellulose. . . . 



"While from 60 to 90 percent of the pentosans in the present experiment have been 

 removed froiu the digestive tract in the jn'ocess of digestion, it has certainly not 

 been demoustrated that they have been assimilated and are of food value equal to that 

 of starch and similar substances. In case of human beings, Ebsteiu has already 

 proved to the coutrary. We hope to be able to throw additional light upon this 

 point in the near future." 



The influence of alum, aluminum hydroxid, and aluminum 

 phosphate on the digestibility of bread, W. 1). JiuiELOw and C. C. 

 Hamilton [Jonr. Amer. Chem. Soc, 16 {189i), No. .9, pp. 587-597). — 

 Bread was made from flour known to be free from alum and aluminum 

 compounds, and the digestibility of the albuminoids determined by 

 digestion with pepsin solution, by Stutzer's and jS'iebling's methods, 

 and by the same methods modified. These different methods of diges- 

 tion gave results agreeing quite closely, 93.26, 93.57, -93.21, 93.28, and 

 93.21 i)er cent of the total albuminoids in the bread being digested. 



Bread was then made to which O.S and 4.28 gm. of crystallized alum, 

 0.54 and 2.5 gm. of aluminum hydroxid, and 0.C4 and 3.2 gm. of 

 aluminum phosphate, respectively, were added per loaf of 2 lbs. The 

 digestibility of the albuminoids was determined in these loaves by the 

 same methods as enumerated above. The addition of alum or aluminum 

 hydroxid appears to have diminished the digestibility from 1 to 25 

 per cent, the larger quantity of aluminum hydroxid having the greater 

 effect. When aluminum phosphate was added the digestibility was 

 decreased about 10 per cent. 



"It is evident that the presence of alum interferes materially with the gastric 

 digestion, but tho aluminum seems to bo precijtitated by the alkali of the pancreatic 

 fluid, so that a jtortiou of the digestion which sliould be effected by the former fer- 

 ment is effected by the latter. . . . 



"The influence of aluminum hydroxid on the digestibility of bread is about the 

 same as that of an equivalent amount of alum when present in about the ([uantity 

 which is usually found as a result of the use of alum baking powder which contains 

 no phos])hatc. 



"The actionof alumiumu i)hos])hatc is quite dift'ereut, however, for notwithstand- 

 ing the supposed insolubility of this coiupound, 10 to 12 per cent of the albuuiinoids 

 which are digestible in the presence of alum or aluminum ]iydroxi<l api)ear to be 

 insolnble in the jiresenco of an equivalent amount of tho ])hosphate."' 



