"During this, the coldest period, the lowlands under the Equator must have been clothed with a mingled tropical and temperate vegetation..." ("Origin," Edition VI., 1882, page 338).) I feel a strong conviction that soon every one will believe that the whole world was cooler during the Glacial period.

Remember Hooker's wonderful case recently discovered of the identity of so many temperate plants on the summit of Fernando Po, and on the mountains of Abyssinia.
(363/5.

"Dr.Hooker has also lately shown that several of the plants living in the upper parts of the lofty island of Fernando Po, and in the neighbouring Cameroon Mountains, in the Gulf of Guinea, are closely related to those on the mountains of Abyssinia, and likewise to those of temperate Europe" (loc.cit., page 337).) I look at [it] as certain that these plants crossed the whole of Africa from east to west during the same period.

I wish I had published a long chapter written in full, and almost ready for the press, on this subject, which I wrote ten years ago.

It was impossible in the "Origin" to give a fair abstract.
My health is considerably improved, so that I am able to work nearly two hours a day, and so make some little progress with my everlasting book on domestic varieties.