528 VRA QMENTS OF SCTKNCE. 
only in degree from those exaggerated manifestations, 
which, in virtue of their magnitude, appeal to our weak 
powers of observation. 
Our conclusion, however, must be based, not on powers 
that we imagine, but upon those that we possess. What do 
they reveal? As the earth and atmosphere offer themselves 
as the nutriment of the vegetable world, so does the latter, 
which contains no constituent not found in inorganic 
nature, offer itself to the animal world. Mixed with cer- 
tain inorganic substances water, for example the vege- 
table constitutes, in the long run, the sole sustenance of 
the animal. Animals may be divided into two classes, the 
first of which can utilize the vegetable world immediately, 
having chemical forces strong enough to cope with its 
most refractory parts; the second class use the vegetable 
world mediately; that is to say, after its finer portions 
have been extracted and stored up by the first. But in 
neither class have we an atom newly created. The animal 
world is, so to say, a distillation through the vegetable 
world from inorganic nature. 
From this point of view all three worlds would constitute 
a unity, in which I picture life as immanent everywhere. 
Nor am I anxious to shut out the idea that the life here 
spoken of may be but a subordinate part and function of 
a Higher Life, as the living moving blood is subordinate to 
the living man. I resist no such idea as long as it is not 
dogmatically imposed. Left for the human mind freely 
to operate upon, the idea has ethical vitality; but, stiffened 
into a dogma, the inner force disappears, and the out- 
ward yoke of a usurping hierarchy takes its place. 
The problem before us is, at all events, capable of 
definite statement. We have on the one hand strong 
grounds for concluding that the earth was once a molten 
mass. We now find it not only swathed by an atmosphere, 
and covered by a sea, but also crowded with living things. 
The question is, How were they introduced? Certainty 
may be as unattainable here as Bishop Butler held it to be 
in matters of religion; but in the contemplation of proba- 
b~ 'ties the thoughtful mind is forced to take a side. The 
collusion of Science which recognizes unbroken causal con- 
nection between the past and the present would undoubtedly 
be that the molten earth contained within it elements of 
life, which grouped themselves into their present forms as 
