illery of our eminent friend Professor Sylvester.

No one knows better than you do, how readily I should defer to the
opinion of so great a mathematician if the question at issue were
really, as he seems to think it is, a mathematical one. But I submit,
that the dictum of a mathematical athlete upon a difficult problem which
mathematics offers to philosophy, has no more special weight, than the
verdict of that great pedestrian Captain Barclay would have had, in
settling a disputed point in the physiology of locomotion.

The genius which sighs for new worlds to conquer beyond that surprising
region in which "geometry, algebra, and the theory of numbers melt into
one another like sunset tints, or the colours of a dying dolphin," may
be of comparatively little service in the cold domain (mostly lighted by
the moon, some say) of philosophy. And the more I think of it, the more
does our friend seem to me to fall into the position of one of those
"verstaendige Leute," about whom he makes so apt a quotation from Goethe.
Surely he has not duly considered two points. The first, that I am in no
way answerable for the origination of the doctrine he criticises: and
the second, that if we are to employ the terms observation, induction,
and experiment, in the sense in which he uses them, logic is as much an
observational, inductive, and experimental science as mathematics; and
that, I confess, appears to me to be a _reductio ad absurdum_ of his
argument.

Thirdly, the essay "On the Physical Basis of Life" was intended to
contain a plain and untechnical statement of one of the great tendencies
of modern biological thought, accompanied by a protest, from the
philosophical side, against what is commonly called Materialism. The
result of my well-meant efforts I find to be, that I am generally
credited with having invented "protoplasm" in the interests of
"materialism." My unlucky "Lay Sermon" has been attacked by
microscopists, ignorant alike of Biology and Philosophy; by
philosophers, not very learned in either Biology or Microscopy; by
clergymen of several denominations; and by some few writers who have
taken the trouble to understand the subject. I trust that these last
will believe that I leave the essay unaltered from no want of respectful
attention to all they have said.

Fourthly, I wish to refer all who are interested in the topics discussed
in my address on "Geological Reform," to the reply with which Sir
William Thomson has