98 HUMAN PHYSIOLOGY 



to amount to 8,000 grains of solid food, 37,650 grains 

 of water, and 13,000 grains of oxygen, making up a 

 total of about 8 pounds of material by weight. His 

 expenditure from the lungs of the waste matter 

 given forth will amount to 20,000 grains, the skin 

 giving off 11,750 grains, the kidneys 24,100 grains, 

 the intestines 2,800 grains of waste digestive matter. 

 The expenditure, amounting to about 8$- pounds, 

 would be found to balance the income. It is 

 impossible for us of course to obtain mathematical 

 exactitude when dealing with living beings, but the 

 figures just given offer as near an approach as is 

 possible to the real facts of the case. 



OUR BODILY PROFIT. Here arises an extremely 

 interesting question, namely, that regarding the profit 

 which is derived from this apparant exact balancing 

 of the income and expenditure. Unless the business 

 of life is conducted on lines widely different from 

 those on which the commercial transactions of men 

 are founded, it is clear the business of living must in 

 one sense be regarded as highly unprofitable, and as 

 showing nothing which may be reckoned in the light 

 of gain. This conception, however, is extremely 

 erroneous, for the profit derived out of the business 

 transactions of life really represents an enormous 

 gain. The profit we obtain, summed up in a single 

 word, is "the power of doing work." Whatever 

 work man performs in the world, his ability to 

 exercise bone, muscle, and brain, is derived from the 

 transaction just chronicled. The case of the engine 

 we may again recall to mind by the statement of the 

 bodily balance sheet. The profit represented by the 

 work of the engine is found in the power which it 

 develops out of the fuel supplied to it. Now in 

 respect of man's inventions this profit is by no 



