284 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



scale goes up. The body is consuming like the cigar — 

 literally burning up and passing away as invisible gas 

 through the nostrils. Probably about two pounds is 

 thus consumed in twenty-four hours. This process of 

 waste is more rapid in higher than in lower animals. It 

 is continuous with life and in proportion to its grade. 

 This may be expressed by the formula : 



i. Waste oc Life. 



2. We have taken the case of absolute rest of body 

 and mind. But suppose next that the subject of this 

 experiment is in violent activity, physical, mental, or 

 moral, perhaps dancing a hornpipe, perhaps wrestling 

 with a mathematical problem, perhaps in intense anx- 

 iety, remorse, or grief. Under these conditions the wast- 

 ing, as measured by pounds, is more rapid. This is ex- 

 pressed by formula 2 : 



2. Waste oc Work. 



3. We will next suppose the subject to be inclosed in 

 a large calorimeter, or instrument for measuring heat by 

 melting of ice. In such case there would be a constant 

 stream of water from the instrument, indicating a con- 

 stant evolution of heat generated by the combustion of 

 waste. Furthermore, the formation of water, and there- 

 fore the generation of heat, would be in proportion to 

 the grade of life and the amount of activity. All this is 

 expressed by formula 3 : 



3. Heat oc Waste oc Life oc Work. 



4. Supply. — Now it is evident that this can not go on 

 continuously without a contrary process, otherwise the 

 body would completely consume itself and exhale in 

 smoke, like the cigar. There must be a supply exactly 

 proportioned to the waste. It is this that creates the neces- 

 sity for food. Food, therefore, must be proportioned to 



