142 THE PROTEIN ELEMENT IN NUTRITION 



experiments be accepted as anything more than a curious 

 physiological feat. 



6. The experiences of zoological gardens, farmers, breeders of 

 cattle, horses, and domestic pets, are all quoted against Chitten- 

 den's conclusions. In fact, he would appear to stand alone 

 against the world in his stringent ideas on protein economy. 



On reading carefully through the accounts of these experiments, 

 two other points appear to be worthy of attention. One is the 

 exceedingly small amount of nitrogen lost to the body in the 

 fseces, being often less than that given for the nitrogen " lost 

 through hair." Thus, for the total of the eleven periods re- 

 cording the nitrogen balances of subject No. 5, the nitrogen lost 

 in the faeces amounts to 5-93 grammes, whilst that lost " through 

 hair " is 5-44 grammes. Another point is that the protein 

 absorption from the dietaries made use of does seem to have 

 fallen as the experiment proceeded. 



Taking subject No. 5 again the only one concerning which 

 we have any details we find the following results : 



DIET I. 



Meat . . . . 172 grms. ] 



Cracker dust . . 124 ,, V Absorption of protein, 91 per cent. 



Lard .. .. 72 J 



DIET II. 



Meat . . . . 70 grms. \ 



Cracker dust . . 124 ,, V Absorption of protein, 93 per cent. 



Lard .. .. 72 J 



i.e., although the highly absorbable protein of meat was 

 reduced from 172 to 70 grammes, the protein absorption from 

 the diet increased by 2 per cent. 



DIET IV. 



Meat . . . . 69 grms. ] 



Bread . . . . 166 ,, !- Absorption of protein, 91 per cent. 



Lard .. .. 80 ,, J 



DIET VI. 



Meat . . . . 70 grms. } 



Cracker dust .. 158 ,, V Absorption of protein, 86 per cent. 



Lard .. .. 60 J 



Contrasting the result shown by Diet VI. with the protein 

 absorption from Diet II., a fall of 7 per cent, would not be 

 expected, unless the intestinal power of absorption had become 

 less efficient as the dieting proceeded. Chittenden, while 

 admitting that the utilization of nitrogen becomes less complete 

 in the later dietaries, attempts to explain it away as being due 



