76 THE PROTEIN ELEMENT IN NUTRITION 



Reference may here be made to the very satisfactory results 

 that followed on an increase in the supply of protein in the 

 Japanese Navy dietary in 1884. The principal changes were the 

 substitution of bread for a large part of the rice and a large 

 increase in the amount of protein of animal origin. 



The following statistics show the improvement in health that 

 followed on the change of diet : 



1878-1883, of 29,321 marines, 9,316, or 32-5 per cent., had beri-beri. 



1884,1 i 718 ') 



JggjJ' Uf 48,275 ,, -] 4 *' lor 1-6 per cent., had beri-beri. 



1887-1889 J 1 3J 



The proportion of other diseases was also very materially 

 decreased. It is not to be wondered at, in the light of these 

 results, that the problems of nutrition attracted great attention 

 in the Navy. 



INVESTIGATIONS IN INDIA. 



We may now take into consideration such information as is 

 available regarding the dietaries of the inhabitants of tropical 

 countries, and the level of nitrogenous metabolism attained. 



Study 1. The first study* carried out was on students and 

 servants of the Medical College, Calcutta. The aim of the 

 investigations was to obtain some idea of the average quantities 

 of the more important constituents present in the urine of the 

 natives of Calcutta with whom there was free choice of food. 



The only point at present necessary to consider is the elimina- 

 tion of nitrogen shown by these observations. Over two hundred 

 analyses were made, and on an average the amount of nitrogen 

 excreted in the urine was just under 6 grammes per man daily. 

 In these observations the subjects of the inquiry had a perfectly 

 free choice of food, and their several conditions in life corre- 

 sponded in every way to that of the great majority of the popula- 

 tion of the rice- eating inhabitants of India. The excretion of 

 6 grammes of nitrogen in the urine would correspond to the 

 metabolism of 35-5 grammes of protein daily, which, even after 

 making allowance for the elimination of metabolized nitrogen 

 in all other secretions and excretions, would mean a very low 

 level of nitrogenous metabolism. Accepting an average of 

 75 per cent, for the absorption of the protein of these dietaries, 

 even under the most favourable circumstances, the average rice- 

 * Scientific Memoirs, Government of India, No. 34, p. 4. 



