THE LIVING MACHINE BUILDING FACTORS. 209 



this matter of the natural explanation of living 

 phenomena, and to picture to ourselves more 

 concisely our knowledge of the living machine. 



The problem we have set before us is to find 

 out to what extent it is possible to account for 

 vital phenomena by the application of ordinary 

 natural laws and forces, and therefore to find out 

 whether it is necessary to assume that there are 

 forces needed to explain life which are different 

 from those found in other realms of nature, 

 or whether vital forces are all correlated with 

 physical forces. It has been evident at a glance 

 that the living body is a machine. Like other 

 machines it consists of parts adjusted to each 

 other for the accomplishment of definite ends, 

 and its action depends upon the adjustment of 

 its parts. Like other machines, it neither creates 

 nor destroys energy, but simply converts the 

 potential energy of its foods into some form of 

 active energy, and, like other machines, its power 

 ceases when the machine is broken. 



With this understanding, the problem clearly 

 resolved itself into two separate ones. The first 

 was to determine to what extent known physical 

 and chemical laws and forces are adequate to an 

 explanation of the various phenomena of life. 

 The second was to determine whether there are 

 any known forces which can furnish a natural 

 explanation of the origin of the living machine. 

 Manifestly, if the first of these problems is insolv- 

 able, the second is insolvable also. 



In the study of the first problem we have 

 reached the general conclusion that the secondary 

 phenomena of life are readily explained by the 

 



