PAET I. 



THE RUNNING OF THE LIVING MACHINE. 



CHAPTER I. 



IS THE BODY A MACHINE ? 



THE problem before us in this section is to find 

 out to what extent animals and plants are 

 machines. We wish to determine whether the 

 laws and forces which regulate their activities 

 are the same as the laws and forces with 

 which we experiment in the chemical and 

 physical laboratory, and whether the principles 

 of mechanics and the doctrine of the conserva- 

 tion of energy apply equally well in the living 

 machine and the steam engine. 



It might he inferred that the proper method 

 of study would be to confine our attention largely 

 to the simplest forms of life, since the problems 

 would be here less complicated, and therefore of 

 easier solution. This, however, has not been nor 

 can it be the method of study. Our knowledge 

 of the processes of life has been derived largely 

 from the most rather than the least complex 

 farms. We have a better knowledge of the 



