TROPICAL FOOD MATERIALS 39 



increased percentage absorption of protein, but also an increase 

 in the total amount of protein undergoing metabolism. The 

 following results * of observations on this point will make the 

 meaning clear : 



In diets containing 30 ozs. of dry rice 6-55 grms. nitrogen were absorbed. 

 26 7-55 



24 

 23 

 20 

 19 



8-00 

 8-09 

 8-40 



8-47 



The explanation of a decrease in the amount of nitrogenous 

 interchange, as the bulk of a diet increases beyond a certain 

 point, is in all probability due to the difficulty experienced by the 

 digestive juices in penetrating the mass, and to dilatation and 

 weakening of the walls of the stomach, inducing a loss of power 

 in the passing on of its contents. Perhaps even more important 

 is the fact that the large mass on reaching the intestines sets up 

 increased peristalsis, so that the contents are hurried on into the 

 large intestine, where protein absorption is at a minimum. The 

 large watery or semi-solid stools passed by prisoners fed on large 

 quantities of rice would lend support to this view. 



It will be obvious from what has been said that where bulk 

 interferes with the protein absorption from a diet no fixed co- 

 efficient for the absorption of the protein of its constituents can 

 be possible. For each separate quantity of rice above a certain 

 amount a different percentage of its contained protein will be 

 absorbed. This was found to be the explanation of the results 

 obtained for the variations in the percentage of protein absorp- 

 tion met with in the bulky diets of prisoners in the gaols of 

 Bengal, and in all probability it would assist in explaining the 

 varying coefficients of the digestibility of rice given by other 

 observers. In Oshima's list the protein absorption of rice ranged 

 in different experiments from 46-5 to 864 per cent. Aron con- 

 firms the results obtained for the protein absorption of rice. 

 His figures vary from 53 to 68 per cent.f 



The decrease in the coefficient of protein absorption with diets 

 containing large amounts of rice may be so great that the total 

 nitrogenous absorption may fall to little more than 50 per cent, 

 of the protein presented in the diet. Thus, on an average, over 

 a large number of experiments on batches of prisoners under 



* Scientific Memoirs, Government of India, No. 37, Chart I. 



f Aron and-Hocson, " Rice as Food," Philippine Journal of Science, 1911, 



