* * *

_The Dell, Grays, Essex. November 15, 1872._

Dear Darwin,--I should have written earlier to thank you for your
book,[94] but was hoping to be able to read more of it before doing so.
I have not, however, found time to get beyond the first three chapters,
but that is quite sufficient to show me how exceedingly interesting you
have made the subject, and how completely and admirably you have worked
it out. I expect it will be one of the most popular of your works. I
have just been asked to write a review of it for the _Quarterly Journal
of Science_, for which purpose I shall be in duty bound to seek out some
deficiencies, however minute, so as to give my notice some flavour of
criticism.

The cuts and photos are admirable, and my little boy and girl seized it
at once to look at the naughty babies.

With best wishes, believe me yours very faithfully,

ALFRED R. WALLACE.

P.S.--I will take this opportunity of asking you if you know of any book
that will give me a complete catalogue of vertebrate fossils with some
indication of their affinities.--A.R.W.

* * * * *

_Down, Beckenham, Kent. January 13, 1873._

My dear Wallace,--I have read your review with much interest, and I
thank you sincerely for the very kind spirit in which it is written. I
cannot say that I am convinced by your criticisms.[95] If you have ever
actually observed a kitten sucking and pounding with extended toes its
mother, and then seen the same kitten when a _little older_ doing the
same thing on a soft shawl, and ultimately an old cat (as I have seen),
and do not admit that it is identically the same action, I am
astonished.

With respect to the decapitated frog,[96] I have always heard of Pflueger
as a most trustworthy observer. If, indeed, anyone knows a frog's habits
so well as to say that it never rubs off a bit of leaf or other object,
which may stick to its thigh, in the same manner as it did the acid,
your objection would be valid. Some of Flourens' experiments, in which
he removed the cerebral hemisphere from a pigeon, indicate that acts
_apparently_ performed consciously can be done without consciousness--I
presume through the force of habit; in which case it would appear that
intellectual power is not brought into play. Several persons have made
such suggestions and objections as yours about the hands being held up
in astonishment:[97] if there was any straining of the muscles,