136 THE STORY OF LIFE'S MECHANISM. 



the difficulties in the way of a solution of the 

 life problem. If the physical basis of life had 

 proved to be a chemical compound, the problem 

 of its origin would have been a chemical one. 

 Chemical forces exist in nature, and these forces 

 are sufficient to explain the formation of any kind 

 of chemical compound. The problem of the origin 

 of the life substance would then have been simply 

 to account for certain conditions which resulted 

 in such chemical combination as would give rise 

 to this physical basis of life. But now that the 

 simplest substance manifesting the phenomena 

 of life is found to be a machine, we can no 

 longer find in chemical forces efficient causes 

 for its formation. Chemical forces and chemi- 

 cal affinity can explain chemical compounds of 

 any degree of complexity, but they cannot 

 explain the formation of machines. Machines 

 are the result of forces of an entirely differ- 

 ent nature. Man can manufacture machines 

 by taking chemical compounds and putting 

 them together into such relations that their 

 interaction will give certain results. Bits of 

 iron and steel, for instance, are put together 

 to form a locomotive, but the action of the 

 locomotive depends, not upon the chemical 

 forces which made the steel, but upon the re- 

 lation of the bits of steel to each other in the 

 machine. So far as we have had any experience, 

 machines have been built under the guidance of 

 intelligence which adapts the parts to each other. 

 When, therefore, we find that the simplest life 

 substance is a machine, we are forced to ask what 

 forces exist in nature which can in a similar way 



