98 THE STORY OF LIFE'S MECHANISM. 



should be applied to the vital activities mani- 

 fested by this substance, protoplasm. While the 

 study of plants and animals was showing scien- 

 tists that natural forces would explain the origin 

 of more complex types from simpler ones through 

 the law of natural selection, here in this concep- 

 tion of protoplasm was a theory which promised 

 to show how the simplest forms may have been 

 derived from the non-living. For an explanation 

 of the origin of life by natural means appeared 

 now to be a simple matter. 



It required now no violent stretch of the 

 imagination to explain the origin of life some- 

 thing as follows : We know that the chemical 

 elements have certain affinities for each other, 

 and will unite with each other under proper con- 

 ditions. We know that the methods of union 

 and the resulting compounds vary with the con- 

 ditions under which the union takes place. We 

 know further that the elements carbon, hydrogen, 

 oxygen, and nitrogen have most remarkable pro- 

 perties, and unite to form an almost endless 

 series of remarkable bodies when brought into 

 combination under different conditions. We 

 know that by varying the conditions the chemist 

 can force these elements to unite into a most 

 extraordinary variety of compounds with an 

 equal variety of properties. What more natural, 

 then, than the assumption that under certain 

 conditions these same elements would unite in 

 such a way as to form this compound protoplasm ; 

 and then, if the ideas concerning protoplasm were 

 correct, this body would show the properties of 

 protoplasm, and therefore be alive. Certainly 



