USE OF THE IMAGINATION. 437 
In more senses than one Mr. Darwin has drawn heavily 
upon the scientific tolerance of his age. He has drawn 
heavily upon time in his development of species, and he 
has drawn adventurously upon matter in his theory of pan- 
genesis. According to this theory, a germ, already micro- 
scopic, is a world of minor germs. Not only is the organ- 
ism as a whole wrapped up in the germ, but every organ of 
the organism has there its special seed. This, I say, is an 
adventurous draft on the power of matter to divide itself 
and distribute its forces. But, unless we are perfectly 
sure that he is overstepping the bounds of reason, that he 
is unwittingly sinning against observed fact or demon- 
strated law for a mind like that of Darwin can never sin 
wittingly against either fact or law we ought, I think, to 
be cautious in limiting his intellectual horizon. If there 
be the least doubt in the matter, it ought to be given in 
favor of the freedom of such a mind. To it a vast 
possibility is in itself a dynamic power, though the pos- 
sibility may never be drawn upon. It gives me pleasure 
to think that the facts and reasonings of this discourse 
tend rather toward the justification of Mr. Darwin, than 
toward his condemnation; for they seem to show the per- 
fect competence of matter and force, as regards divisibility 
and distribution, to bear the heaviest strain that he has 
hitherto imposed upon them. 
In the case of Mr. Darwin, observation, imagination, 
and reason combined have run back with wonderful 
sagacity and success over a certain length of the line of 
biological succession. Guided by analogy, in his " Origin 
of Species " he placed at the root of life a primordial germ, 
from which he conceived the amazing variety of the or- 
ganisms now upon the earth's surface might be deduced. 
If this hypothesis were even true, it would not be final. 
The human mind would infallibly look behind the germ, 
and however hopeless the attempt, would inquire into the 
history of its genesis. In this dim twilight of conjecture 
the searcher welcomes every gleam, and seeks to augment 
his light by indirect incidences. He studies the methods 
of nature in the ages and the worlds within his reach, in 
order to shape the course of speculation in antecedent ages 
and worlds. And though the certainty possessed by experi- 
mental inquiry ife here shut out, we are not left entirely 
without guidance, From the examination of the solar 
