282 The Ohio Journal of Science [Vol. XVIII, No. 7, 



The feces from the three days weighed 248 grams moist, and 

 66.6 grams air-dry. They contained: 



Percent Grams 



Moisture 7.25 4.82 



Ash 19.70 13.12 



Protein 27.66 18.82 



Crude fiber 8.46 5.63 



Fat 22.01 14.65 



N-free extract 15.22 10. 14 



In addition to undigested food residues, feces always contain 

 nitrogenous metabolic products derived (1) from the digestive 

 fluids and (2) from mucous and epithelial cells from the walls of 

 the digestive tract. In order to determine the amount of these 

 metabolic products a basal ration consisting of milk, butter, 

 sugar, starch and agar, and designed to yield feces of about the 

 same bulk as in the soy bean period was eaten. The diet was 

 as follows: 



3000 grams milk 

 275 grams butter 

 150 grams cane sugar 



130 grams potato starch, boiled in water to make a pudding. 

 36 grams agar, eaten dry and raw.* 



One-third of the above was consumed daily for a three-day 

 period. The resulting feces weighed 270 grams moist, and 55.6 

 grams air-dry, and contained: 



Percent Grams 



Moisture 5.36 2.98 



Ash 19.50 10.85 



Protein 11.90 6.60 



Fat 31.20 17.34 



Crude fiber 1.40 .77 



N-free extract 30.60 17.03 



The protein in the feces of this period represents metabolic 

 products from the digestive juices and intestinal walls as well 

 as some unabsorbed protein from the milk. Deducting this 

 from the protein eliminated in the feces during the soy bean 

 period we have 18.82 — 6.60=12.22 grams, which represents the 

 unabsorbed protein from the wheat flour and soy bean meal. 

 This gives a coefficient of digestibility for the total protein of 

 the bread of 91.3. Assuming that protein of patent wheat flour 

 is 88.6^^ per cent digestible the coefficient of digestibility of the 

 soy bean meal protein becomes 93. This is hardly fair, however, 

 since the coefficient 88.6 was obtained without making a cor- 



* The agar contained 6.35 percent of ash and 15.75 percent of moisture. 



