42 THE LIVING WORLD. 



an almost infinite variety of compounds, each with 

 its own peculiar properties. Some of these com- 

 pounds were so stable as to continue to exist down 

 to the present day, almost unchanged. Others were 

 constantly changing. The compounds of carbon 

 especially were varied and unstable, as we may con- 

 clude from the compounds of that element known 

 to-day. Many of these carbon compounds doubtless 

 would disappear with a change of conditions, break- 

 ing up, to enter into other combinations and form 

 other unstable compounds. Now amid this continued 

 succession of changes, the conditions of heat, elec- 

 tricity, etc., might at one time have been such as to 

 cause the elements, carbon, oxygen, hydrogen, and 

 nitrogen, all of which were present in the atmosphere, 

 to unite into certain complex bodies approximating 

 organic compounds. That this is a possibility be- 

 comes evident when we remember that our chemists 

 have already begun to make these elements unite 

 by laboratory methods. Many organic compounds 

 have been synthetically manufactured from inor- 

 ganic material. Most of these compounds of early 

 times probably did not continue to exist very long, 

 since they were unstable, and had no power of self- 

 preservation. 



' Thus far perhaps no one will hesitate to follow 

 the scientist, since he is dealing with authentic facts 

 rather than with speculation. But now he takes a 

 step into the dark. He supposes that at one time 

 these elements united into a compound which was, 

 owing to its peculiar composition, capable of causing 

 other bodies to change. By virtue of this power 



