PRIMEVAL CONDITIONS DIFFERED, 341 
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 primeval 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 atmosphere 
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 primeval ocean, which 
then continuously covered the whole surface of the earth as 
an uninterrupted watery sheet, was quite peculiar. The 
temperature, the density, the amount of salt, etc., must have 
been very different from those of the present ocean. In 
