RELATION OF FOOD TO WORK, AND 283 



Performing this calculation we find — 



Carbonic 



1 5.522 



2 7.440 



3 18.100 



4 25.830 



5 44.973 



It is easy to calculate that the external work clone in the cases 3, 4, 

 5, was as follows : 



External work. 



No. 3. Walking two miles per hour 0.1000 mile. 



No. 4. Walking three miles per hour 0.1500 mile. 



No. 5. Tread-mill - 0.3256 mile. 



Subtracting these amounts of work from the applied work, due to the 

 production of carbonic acid, we find, as the quantities left for vital 

 work, including circulation and respiration, and for the production of 



animal heat, per hour r 



Vital work and 

 animal heat. 



No. 3 0.3591 mile. 



No. 4 0.5051 mile. 



No. 5 0.8150 mile. 



As I have already shown the work due to animal heat per day to be 

 6 miles, it follows that the work of animal heat per hour is 0.2500 mile. 

 Deducting this amount from the foregoing, we find for the vital work 

 done, under the three different conditions — 



Vital work. 



No. 3. Walking at two miles per hour 0.1001 mile. 



No. 4. Walking at three miles per hour 0.2551 mile. 



No. 5. Tread-mill work 0.5650 mile. 



This result proves, in a striking manner, the great disadvantage under 

 which an increased amount of muscular work is done in a given time; 

 and it is quite in accordance with other results obtained by me from 

 totally different experiments. 



No two classes of animals can well differ more from each other than the 

 cats and ruminants, one of which is intended by nature to eat the other. 

 They differ in all respects as to food, the cats requiring a supply of fresh 

 meat and blood for their health, and the ruminants being exclusively 

 vegetable-feeders; yet in both classes we find a great development of 

 muscular powes, and of rapid action of muscles, qualities alike neces.'?ary 

 to the pursuer and to the pursued. There can be no doubt that muscular 

 work is developed in the cats from the combustion of flesh, and in the 

 ruminants, maiidy, if not exclusively, from farinaceous food. It is, how- 

 ever, worthy of remark, that the muscular qualities developed by the 

 two kinds of food differ considerably from each other. The hunted deer 



