138 THE BEGINNINGS OF LIFE. 



of the circumstances in the state of the atmosphere 

 calculated to favour the development of one and to 

 oppose that of the other ? 



'Under what form at the epoch of the creation of 

 organized beings did the whole of the carbon exist 

 which these beings subsequently absorbed, and which 

 is now buried with their spoils in the bosom of the 

 earth, or which is still met with distributed among 

 the infinite multitude of organized beings that actually 

 cover the face of our globe ? 



' It is obvious that animals derive carbon neither 

 from the atmosphere nor the soil, but exclusively from 

 their food. 



c We cannot conceive how plants could have assimi- 

 lated this carbon had it been in the solid state ; and, 

 moreover, in the formations older than those that 

 include the first remains of vegetables, we scarcely 

 encounter any traces of carbon. 



c This carbon, then, which the vegetables of the 

 primitive world, and those of the subsequent and 

 present world, absorbed, must necessarily have existed 

 in a shape pioper to furnish them with nutriment; 

 and we only know of two humus or vegetable mould, 

 which, resulting itself from the decomposition of other 

 vegetables, would lead us into a vicious circle, and 

 carbonic acid, which, decomposed by the leafage of 

 vegetables under the influence of solar light, deposits 

 its carbon, and so serves for their growth. 



c lt appears to me impossible, therefore, to suppose 



