ing been to do as little as
possible while resting. I feel sure that you have laid a broad and safe
foundation for all future work on Distribution. How interesting it will
be to see hereafter plants treated in strict relation to your views; and
then all insects, pulmonate molluscs and fresh-water fishes, in greater
detail than I suppose you have given to these lower animals. The point
which has interested me most, but I do not say the most valuable point,
is your protest against sinking imaginary continents in a quite
reckless manner, as was stated by Forbes, followed, alas, by Hooker,
and caricatured by Wollaston and [Andrew] Murray! By the way, the main
impression that the latter author has left on my mind is his utter want
of all scientific judgment. I have lifted up my voice against the above
view with no avail, but I have no doubt that you will succeed, owing
to your new arguments and the coloured chart. Of a special value, as it
seems to me, is the conclusion that we must determine the areas, chiefly
by the nature of the mammals. When I worked many years ago on this
subject, I doubted much whether the now-called Palaearctic and Nearctic
regions ought to be separated; and I determined if I made another region
that it should be Madagascar. I have, therefore, been able to appreciate
your evidence on these points. What progress Palaeontology has made
during the last twenty years! but if it advances at the same rate in the
future, our views on the migration and birthplace of the various groups
will, I fear, be greatly altered. I cannot feel quite easy about the
Glacial period, and the extinction of large mammals, but I must hope
that you are right. I think you will have to modify your belief about
the difficulty of dispersal of land molluscs; I was interrupted when
beginning to experimentise on the just hatched young adhering to the
feet of ground-roosting birds. I differ on one other point--viz. in the
belief that there must have existed a Tertiary Antarctic continent, from
which various forms radiated to the southern extremities of our present
continents. But I could go on scribbling forever. You have written, as
I believe, a grand and memorable work, which will last for years as the
foundation for all future treatises on Geographical Distribution.

P.S.--You have paid me the highest conceivable compliment, by what
you say of your work in relation to my chapters on distribution in the
"Origin," and I heartily thank yo