TROPICAL FOOD MATERIALS 61 



It will be noticed that over half of the nitrogen of this diet is 

 derived from the pulses, which is beyond the percentage from 

 which the maximum protein absorption will be obtained. From 

 the coefficients of digestibility worked out for the different food- 

 stuffs present in this diet, over 60 per cent, of its nitrogen should 

 have been absorbed, so that the excessive quantities of pulse 

 cause decrease in the actual and relative absorption of its protein 

 element. 



In connection with this point Church states : " The digesti- 

 bility of the albuminoids in pulse as compared with that of the 

 corresponding compounds in the cereals has usually been regarded 

 as low. In general, they are not only digested and absorbed at 

 a slower rate, but a larger proportion of the total amount present 

 remains unattacked and unused in its passage through the 

 alimentary canal. The proportion of unused to used albuminoids 

 is proportionately highest when the pulse forms the largest part 

 of the ration ; it is much reduced when the pulse constitutes not 

 more than one-fourth of the daily food."* It was found in 

 dealing with the gaol dietaries of Bengal and the United Provinces 

 that it was useless to increase the quantity of pulse beyond an 

 average of 5 ounces per man daily. Larger quantities than this 

 seem to act more as an irritant than as a food, and have a decided 

 tendency to set up diarrhoea, thus seriously deteriorating the 

 value of the diet. 



In dietaries where the pulse is improperly cooked as, for 

 instance, is the case in the method of parching gram dal it is 

 probable that a large proportion of the contained nutriment never 

 comes into thorough contact with the digestive juices, and passes 

 out in the fseces practically unchanged. Gram dal, on this 

 account partly at least, showed the poorest percentage of protein 

 absorption of all the pulses investigated. With regard to the 

 other factor that was found to affect the protein absorption from 

 the pulses viz., the total bulk of the diet experiments carried 

 out with the voluminous rice dietaries of Bengal prisoners showed 

 that it was futile to increase the nitrogen intake by the addition 

 of pulse beyond a certain optimum quantity, in the hope of 

 obtaining an augmented protein absorption. 



From actual observationsf it was demonstrated that, with a 

 constant intake of nitrogen derived from rice, but with a varying 



* Church, " Food Grains of India." 



f Scientific Memoirs, Government of India, No. 37, pp. 66-71. 



