SPONTANEOUS GENERATION, 327 
It was not till the earth’s crust had so far cooled that the 
water had condensed into a fluid form, it was not till the 
hitherto dry crust of the earth had for the first time become 
covered with liquid water, that the origin of the first 
organisms could take place. For all animals and all plants— 
in fact, all organisms—consist in great measure of fluid 
water, which combines in a peculiar manner with other sub- 
stances, and brings them into a semi-fluid state of aggrega- 
tion. We can therefore, from these general outlines of the 
inorganic history of the earth’s crust, deduce the important 
fact, that at a certain definite time life had its beginning on 
earth, and that terrestrial organisms did not exist from 
eternity, but at a certain period came into existence for the 
first time. 
Now, how are we to conceivé of this origin of the first 
organisms? This is the point at which most naturalists, 
even at the present day, are inclined to give up the attempt 
at natural explanation, and take refuge in the miracle of an 
inconceivable creation. In doing so, as has already been re- 
marked, they quit the domain of scientific knowledge, and 
renounce all further insight into the eternal laws which have 
determined nature’s history. But before despondingly taking 
such a step, and before we despair of the possibility of 
any knowledge of this important process, we may at least 
make an attempt to understand it. Let us see if in reality 
the origin of a first organism out of inorganic matter, the 
origin of a living body out of lifeless matter, is so utterly 
inconceivable and beyond all experience. In one word, let 
us examine the question of spontaneous generation, or archi- 
gony. In so doing, it is above all things necessary to form 
a clear idea of the principal properties of the two chief 
