d even still
more by your paper in the _Annals_,[28] a year or more ago, I can plainly
see that we have thought much alike and to a certain extent have come to
similar conclusions. In regard to the paper in the _Annals_, I agree to
the truth of almost every word of your paper; and I daresay that you
will agree with me that it is very rare to find oneself agreeing pretty
closely with any theoretical paper; for it is lamentable how each man
draws his own different conclusions from the very same fact. This summer
will make the twentieth year (!) since I opened my first note-book on
the question how and in what way do species and varieties differ from
each other. I am now preparing my work for publication, but I find the
subject so very large, that though I have written many chapters, I do
not suppose I shall go to press for two years.

I have never heard how long you intend staying in the Malay Archipelago;
I wish I might profit by the publication of your Travels there before my
work appears, for no doubt you will reap a large harvest of facts.

I have acted already in accordance with your advice of keeping domestic
varieties, and those appearing in a state of nature, distinct; but I
have sometimes doubted of the wisdom of this, and therefore I am glad to
be backed by your opinion. I must confess, however, I rather doubt the
truth of the now very prevalent doctrine of all our domestic animals
having descended from several wild stocks; though I do not doubt that it
is so in some cases. I think there is rather better evidence on the
sterility of hybrid animals than you seem to admit: and in regard to
plants, the collection of carefully recorded facts by Koelreuter and
Gaertner (and Herbert) is _enormous_. I most entirely agree with you on
the little effect of "climatic conditions" which one sees referred to
_ad nauseam_ in all books: I suppose some very little effect must be
attributed to such influences, but I fully believe that they are very
slight. It is really _impossible_ to explain my views in the compass of
a letter as to causes and means of variation in a state of nature; but I
have slowly adopted a distinct and tangible idea--whether true or false
others must judge; for the firmest conviction of the truth of a doctrine
by its author seems, alas, not to be the slightest guarantee of truth.

I have been rather disappointed at my results in the poultry line; but
if you should, after receiving this, stumble on any curi