PRIMEVAL CONDITIONS DIFFEHED. 347 



manner, we can by no means draw the conclusion that 

 spontaneous ^generation in general is impossible. The 

 impossibility of such a process can, in fact, never be proved. 

 For how can we know that in remote primaeval times there 

 did not exist conditions quite different from those at 

 present obtaining, and which may have rendered spon- 

 taneous generation possible ? Indeed, we can even positively 

 and with full asssurance maintain that the general 

 conditions of life in primaeval times must have been entirely 

 different from those of the present time. Think only of the 

 fact that the enormous masses of carbon which we now 

 find deposited in the primary coal mountains were first 

 reduced to a solid form by the action of vegetable life, and 

 are the compressed and condensed remains of innumerable 

 vegetable substances, which have accumulated in the course 

 of many millions of years. But at the time when, after 

 the origin of water in a liquid state on the cooled 

 crust of the earth, organisms were first formed by 

 spontaneous generation, those immeasurable quantities of 

 carbon existed in a totally different form, probably for the 

 most part dispersed in the atmosphere in the shape of 

 carbonic acid. The whole composition of the atmosj)here 

 was therefore extremely different from the present. 

 Further, as may be inferred upon chemical, physical, and 

 geological grounds, the density and the electrical conditions 

 of the atmosphere were quite different. In like manner the 

 chemical and physical nature of the primaeval ocean, which 

 then continuously covered the whole surface of the earth as 

 an uninterrupted watery sheet, was quite peculiar. Tht,* 

 temperature, the density, the amount of salt, etc., must have 



been very different from those of the present ocean. In 

 16 



