IS THE BODY A MACHINE? 35 



is immediately seen in a rise in temperature of 

 the apparatus. But even with this delicacy 

 the apparatus is comparatively coarse, and can 

 measure only the most apparent forms of 

 energy. The more subtile types of energy, such 

 as nervous force, if this is to be regarded as 

 energy, do not make any impression on the 

 apparatus. 



The obstacles in the way of these experiments 

 do not particularly concern us, but the general 

 results are of the greatest significance for our 

 purpose. While, for manifest reasons, it has 

 not been possible to carry on these experi- 

 ments for any great length of time, and while 

 the results have not yet been very accurately 

 refined, they are all of one kind and teach un- 

 hesitatingly one conclusion. So far as concerns 

 measurable energy or measurable material, the 

 body behaves just like any other machine. If 

 the body is to do work in this respiration 

 apparatus, it does so only by breaking to pieces 

 a certain amount of food and using the energy 

 thus liberated, and the amount of food needed is 

 proportional to the amount of work done. When 

 the individual simply walks across the floor, or 

 even rises from his chair, this is accompanied 

 by an increase in the amount of food material 

 broken up and a consequent increase in the 

 amount of refuse matter eliminated and the heat 

 given off. The income and outgo of the body in 

 both matter and energy is balanced. If, during 

 the experimental period, it is found that less 

 energy is liberated than that contained in the 

 food assimilated, it is also found that the body 



