IN THE ANIMAL ORGANISM. 237 



luntary motions (those of the heart and intestines, 

 for example) cease, and apparent death or syncope 

 supervenes. 



It is obvious that the cause of the generation of 

 force, namely the change of matter, is diminished, 

 because, with the abstraction of heat, as in the plant 

 by abstraction of light, the intensity of the vital force 

 diminishes. It is also obvious that the momentum 

 of force in a living part depends on its proper tem- 

 perature; exactly as the effect of a falling body 

 stands in a fixed relation to certain other conditions ; 

 for example, to the velocity attained in falling. 



When the temperature sinks, the vital energy 

 diminishes ; when it again rises, the momentum of 

 force in the living parts appears once more in all its 

 original intensity. 



The production of force for mechanical purposes, 

 and the temperature of the body, must, consequently* 

 bear a fixed relation to the amount of oxygen which 

 can be absorbed in a given time by the animal body. 



The quantities of oxygen which a whale and a 

 carrier's horse can inspire in a given time are very 

 unequal. The temperature, as well as the quantity 

 of oxygen, is much greater in the horse. 



The force exerted by a whale, when struck with 

 the harpoon, his body being supported by the sur^ 

 rounding medium, and the force exerted by a car- 

 rier's horse, which carries its own weight and a 

 heavy burden for eight or ten hours, must both l>ear 

 the same ratio to the oxygen consumed. If we 



