330 Proceedings of Royal Society of Edinburgh. [sess. 
knowledge as to the digestibility of different foods, as well as 
working with an improved calorimeter, Atwater and Bryant * 
suggest 4*0 as the factor for proteids and carbohydrates, and 8*9 
for fats. Rubner’s estimate is the one generally used. 
The Calorific value cannot he taken as a rigid means of 
comparison between two dietaries, hut it is none the less of great 
value. In order to perform severe muscular work, a diet of high 
energy value must he consumed. Since carbohydrates and fats 
are the main source of energy, at first sight it seems as if an 
increase in these nutrients would meet the requirements. But 
most people find that digestive disturbances are set up by a high 
fat and carbohydrate diet, and the increased amount of food must 
of necessity be proteid. 
A practical application of this point is seen in Dunlop’s Report 
to the Prison Commissioners.! The diet of certain convicts was 
of an energy value of 3928 Calories, and the waste was great. 
There was no waste when the diet was reduced to 3517 Calories, 
hut the prisoners lost weight, and complaints were rife. When 
74 grammes of bread were added to the ration, the diet was of 
3707 Calories. There was no further loss of weight, the complaints 
ceased, and the waste was inconsiderable. 
The dietary standards fixed by different authorities may be 
tabulated : — 
Proteids, 
grammes. 
Fats, 
grammes. 
Carbo- 
hydrates, 
grammes. 
Calories. 
Voit . 
118 
56 
500 
3054 
Riibner 
127 
52 
509 
3091 
Playfair 
119 
51 
531 
3139 
Moleschott . 
130 
40 
550 
3160 
Atwater 
125 
125 
450 
3520 
It is interesting to compare these with the results of Chittenden’s 
experiments, in which the proteid varied from 44-50 grammes 
daily, with a Calorific value of 1550-3000 from the entire 
food. 
* Connecticut Storrs Station Report, p. 73. 
t See also “ Food Requirements of Various Labour,” Scottish Medical and 
Surgical Journal, 1901. 
