16 PROCEEDINGS OF THE ACADEMY OF [1897. 



Continued refrigeration must, in time, repress this organic activ- 

 ity and bring it finally to an end, the chemical inertness once due to 

 extreme heat being paralleled by a similar inertness due to extreme 

 cold. The interval between is that of the earth's chemical history. 

 In the history of chemistry we ]:>erceive, therefore, two great cycles, 

 an inorganic one, whose principal feature is oxidation, which reached 

 its culmination in the remote past, and an organic one, whose prin- 

 cipal feature is deoxidation, which is now at its culminating poiut. 



The question which naturally follows is : When did inorganic ac- 

 tivity cease, and organic activity begin, and to what extent is the 

 latter an outgrowth from the former? The reduction of the temper- 

 ature of the ocean had much to do with this change, inorganic action 

 being probably favored by a high temperature, while organic action 

 may have been impossible in waters much above 212°. These two 

 phases of chemical activity differ strikingly in one particular. In- 

 organic chemism had a fixed period of duration, beyond which it 

 could not exist. When there remained no more substance in con- 

 dition to be seized upon by oxygen, this phase of chemical action 

 necesssarily ceased. Organic chemism has no such limitation. It 

 may continue in activity, under favorable conditions of temperature 

 and sunlight, indefinitely, its material being practically inexhaust- 

 ible. Only decrease in temperature can bring it to an end. 



As the waters of the primeval ocean slowly cooled, and inorganic 

 chemism declined in activity, organic chemism probably set in, 

 aided by the solar rays, then perhaps first freely reaching the waters. 

 The material for this new phase of action had been prepared before 

 and existed abundantly in the water and air. It may have had its 

 origin in an early reaction between carbon dioxide and the elements 

 of water, yielding the hydro-carbons ; and subsequently between 

 these and nitrogen, yielding the far more complex albuminous com- 

 pounds. 



Certainly organic forms appeared in the waters of that period, 

 and conditions favoring their formation must have existed. We do 

 not know through what successive steps of chemical combination the 

 complex organic molecules arose. We do know that many of the 

 preceding mineral molecules were quite complex in composition, 

 and can reasonably deduce from this that still more complex mole- 

 cules arose under conditions restraining the activity of oxygen. 

 Seed forms of organic substance may have first appeared — simple 

 carbon compounds. These would serve as the basis of more complex 



