FOODS — HUMAN NUTRITION. 663 



The coefficients of digestibility found for cotton seed were from 67 to 75 

 per cent, as contrasted with from 88 to 93 per cent for meat diets containing 

 comparable or greater amounts of indigestible nonnitrogenous substances. 

 While the authors give no opinion regarding the cause of this manifestly poor 

 utilization of cotton-seed nitrogen, they suggest that the cotton-seed flour may 

 have contained some constituent which inhibited secretion or promoted pre- 

 mature evacuation. 



Studies in nutrition. — VI, The utilization of the proteins of extractive- 

 free meat powder; and the origin of the fecal nitrogen, L. B. Mendel and 

 M. S. Fine (Jour. Biol. Vhcm., 11 (1<)I2), A'o. /, pi). .5-26).— The authors call 

 attention to the literature of the subject and describe digestion experiments 

 with dogs in which a powdered meat residue containing 13.2 per cent of nitrogen 

 was fed. 



They summarize their results as follows : 



" The utilization of the nitrogen of meat powder is distinctly, althqugh 

 slightly, lower than that of fresh meat. The relatively high nitrogen concen- 

 tration of the meat powder feces is indicative of a loss of this material through 

 the excrement." 



In the second part of the paper the nitrogen of the feces under a variety of 

 conditions is discussed briefly from the historical aspect; data purporting to 

 show to what extent indigestible nonnitrogenous sub.stances may influence the 

 amount and character of the feces are presented ; and a plan of experimenta- 

 tion is proposed, with which it seems possible to determine approximately to 

 what degree the nitrogen excreted in the feces is derived from undigested or 

 indigestible nitrogenous constituents of the ingesta. This involves (1) the 

 determination of nitrogen of feces resulting from the material under investiga- 

 tion ; (2) the determination and subtraction from the above-mentioned quan- 

 tity of the fecal nitrogen resulting from a nitrogen-free diet to which has been 

 added an amount of indigestible nonnitrogenous matter that will yield approxi- 

 mately the same volume of feces as was obtained from the material specially 

 studied. Any excess of nitrogen is presumably due to undigested or unabsorbed 

 nitrogenous matter of the food material. 



"About the thorough utilization of the proteins of wheat there is no question. 

 The probability that those of barley and corn are equally available was pointed 

 out in previous papers of this series. With regard to the legume proteins we 

 must for the present conclude that the presence of indigestible nonnitrogenous 

 materials can not entirely account for their low coefficients of digestibility. 

 These proteins appear to be less readily affected by the digestive processes than 

 those of barley or corn. This resistance is even more pronounced in the case of 

 the cotton-seed protein. Nevertheless, future research with the isolated pro- 

 teins may modify our opinion with regard to these last 2 classes of materials. 



" The lack of animal extractives in vegetable materials has at times been 

 thought to be the cause of the apparently poor utilization of plant foods in 

 comparison with those of animal origin. . . . The fact that the proteins of 

 wheat, and probably those of barley and corn also, are thoroughly utilized lends 

 support to the view that the secretory influences of the extractive materials 

 play a minor role in the ultimate utilization. It was pointed out in an earlier 

 paper (E. S. R., 25, p. 864) that certain wheat preparations evoked intense 

 nausea in man, and necessitated forced feeding in the dog experiments, but 

 were, nevertheless, thoroughly digested. This would suggest that psychic 

 secretion does not influence the ultimate utilization to any great extent." 



The relation between the protein condition of the body and the amount 

 of protein in the diet, M. Rubner (Arch. Anat. u. Physiol., Physioh Aht., 1911, 

 No. 1-2, Pit. 61-66; ahs. in Chem. Zentbl., 1911, II, No. 9, p. 626). — Theoretical 



