222 University of California Publications in Zoology [Vou.9 
they open to the scientific imagination. For instance, what better 
experimental approach to the panspermia hypothesis advocated 
by Lord Kelvin, Professor Arrhenius and others, can be sug- 
gested than is here presented? If organic ‘‘germs’’—better 
minute organisms—are carried about through all space, starting 
from and lodging upon the great bodies of the universe, here, 
there, everywhere, and all the time, what more promising place 
to hunt for those that may land on and pass from our earth, 
than the vast expanses of the sea which for eons have surely 
been both the germinating and the conserving beds of myriads 
upon myriads of organic beings? 
Only a few years ago the notion of such universal dissemina- 
tion of organisms could have had no standing outside the realm 
of poetic faney. Now, however, that it is backed up by weighty 
scientific observation and deduction, and can be given a place 
in a soberly laid out programme of scientific investigation, one 
ean hardly avoid stopping for a moment to ask, What after all 
is the difference between poetic imagination and _ scientific 
imagination? Is it not chiefly that the first runs on with a 
minimum of conscious reference to past objective experience and, 
rightly enough, neither asks nor cares much about future testing 
by the same sort of experience; while the latter demands a basis 
of considerable well-attested observations to start with, and looks 
forward to much rigorous testing by that same means? The 
interesting thing about this view of imagination is that accord- 
ing to it we are not dealing with two wholly distinct imagina- 
tions, but rather with one imagination used in two radically 
different ways. Science finds itself in a favorable position to 
realize the truth of this view when on rare occasions of which 
the present would seem to be one, it moves well to the front in 
some of its largest provinces. Incidentally it is wholesome to 
be led to see definitely that poetry and science, though so far 
asunder in their parts most remote from each other, really inter- 
blend in their nearest parts. Poetry has its truth primarily in 
man’s imaginative and subjective nature and only secondarily 
in his objectively experiential nature ; while science has its truth 
primarily in his objectively experiential and rational existence, 
and only secondarily in his imaginative and subjective existence. 
