656 FRAGMENTS OF SCIENCE. 
after describing the most distant of well-defined objects, 
he should give utterance also to some of the subjective 
impressions which he is conscious of receiving from regions 
beyond; if he should depict possibilities which seem open- 
ing to his view; if he should explain why he thinks this a 
mere blind alley and that an open path; then the fault and 
the loss would be alike oars if we refused to listen calmly, 
and temperately to form our own judgment on what we 
hear} then assuredly it is we who would be committing the 
error of confounding matters of fact with matters of opin- 
ion, if we failed to discriminate between the various ele- 
ments contained in such a discourse, and assumed that 
they had been all put on the same footing." 
While largely agreeing with him, I cannot quite accept 
the setting in which Professor Virchow places the confess- 
edly abortive attempts to secure an experimental basis for 
the doctrine of spontaneous generation. It is not a doctrine 
" so discredited "4liat some of the scientific thinkers of 
England accept " as the basis of all their views of life." 
Their induction is by no means thus limited. They have 
on their side more than the "reasonable probability" 
deemed sufficient by Bishop Butler for practical guidance 
in the gravest affairs that the members of the solar system 
which are now discrete once formed a continuous mass; 
that in the course of untold ages, during which the work of 
condensation, through the waste of heat in space, went on, 
the planets were detached; and that our present sun is the 
residual nucleus of the flocculent or gaseous ball from 
which the planets were successively separated. Life, as 
we define it, was not possible for aeons subsequent to this 
separation. When and how did it appear? I have already 
pressed this question, but have received no answer.* If, 
with Professor Knight, we regard the Bible account of the 
introduction of life upon the earth as a poem, not as a 
statement of fact, where are we to seek for guidance as to 
the fact? There does not exist a barrier possessing the 
strength of a cobweb to oppose to the hypothesis which 
ascribes the appearance of life to that " potency of matter " 
* In the " Apology for the Belfast Address," the question is rea- 
out. 
