126 THE PROTEIN ELEMENT IN NUTRITION 



That is, extreme differences of 15-5, 13-7, and 8-6 per cent, in 

 the absorption of protein are shown by the several subjects experi- 

 mented with on the same diet during the three periods of nitrogen 

 balance. That such large variations could be met with in normal 

 healthy people is scarcely credible. Benedict quotes the results 

 of forty-eight digestion experiments in which the same food was 

 administered to thirty different individuals : Of 40 grammes of 

 nitrogen ingested during a three-day experiment, 4-7 grammes 

 were recovered in the faeces, whilst in the large majority of the 

 experiments the variation was but 2 or 3 decigrammes on either 

 side of the normal. It has now been well recognized that the 

 percentage composition of the faeces under all diets is so uniform 

 that some speak of foods as large or small faeces-producers, rather 

 than as being capable of incomplete or complete absorption. In 

 our work* on the dietaries of Bengal gaols, the percentages of 

 nitrogen in the faeces was found to be fairly uniform under dif- 

 ferent conditions, whilst the total loss of nitrogen varied largely 

 with the total weight of the stools passed. Also, over a very large 

 number of observations made on prisoners f in the United Pro- 

 vinces, the percentage of nitrogen in the faeces was found to vary 

 within very narrow limits, whatever the composition of the diet 

 happened to be, whilst the total amount of faecal matter and the 

 total loss of nitrogen to the body varied directly with the weight 

 of the dietary, so long as it was composed of the same food 

 materials. 



Some of the results obtained with batches of prisoners may be 

 quoted to show how very little variation in the absorption of 

 protein is met with in different individuals when on identical 

 dietaries (see table, p. 127). 



Although these diets are seemingly identical, the fact that the 

 foodstuffs forming them differed considerably in chemical com- 

 position in the several gaols introduces extraneous factors in a 



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

 t Ibid., No. 48, pp. 177-185. 



