270 Dr. Robert Hutchison [March 9, 



Metabolic Balance Sheet. 



Man of 56 kilos. 



Expenditure op Energy. Income as Food. 



Cals. Cals. 



1. Internal work (heart, respira- 118 grms. proteid 484 



tion, heat-production) . . 1550 56 ,, fat 521 



2. Digestive work 240 500 „ carbohydrate . . . . 2050 



3. External or muscular work : 



{a) Actual work done 250 Total 3055 



(6) Increase under (1) 590 



840 



Total 2630 



Balance 425 = 45 grms. fat, or 2 oz. adipose tissue. 



Attention being first confined to the expenditure side of the 

 balance sheet, the nature of the outgoings of energy in each item 

 under this heading was briefly explained. It was pointed out that 

 the exact amount of energy expended under each head varied greatly 

 in different circumstances and individuals. 



(1) The amount of " internal work " depended upon body- 

 weight, the proportion of fat and muscle, the age, and most of all, 

 upon the extent of body-surface. The latter factor was of the 

 greatest importance as determining heat loss, and variations in the 

 amount of energy consumed by different persons could be largely 

 explained by it. This was illustrated by the fact that if we stated 

 the amount of energy required at different ages in terms of body- 

 surface, the results were surprisingly uniform. 



(2) The amount of the digestive work varied with the composi- 

 tion, and especially with the bulk of the food. The influence of 

 bulk was so important that it had been calculated that if a horse 

 were fed upon hay alone, 48 per cent, of the energy in the hay was 

 expended in its digestion. 



(3) The influence of external work upon expenditure required 

 little explanation, but stress was laid upon the large increase which 

 even slight degrees of work might entail. Thus 12 per cent, more 

 of energy was expended when standing at attention than when 

 standing at ease, whilst an hour's brisk walk increased the output of 

 energy by 260 cals. Further, one must remember that any increase 

 in external work increased also the expenditure under all the items 

 classed as " internal work " as well. Apart from such variations as 

 these, the question was raised whether there might not be individual 

 variations in metabolism of which we are not yet able to give an 

 exact account. Temperament, for example, was of importance, as 

 determining the performance of superfluous movements, and in the 

 rate at which muscular efforts took place. Apart from this, it was 



