criticised, and even when I have been overpraised, so that I have
felt mortified, it has been my greatest comfort to say hundreds
of times to myself that "I have worked as hard and as well as I
could, and no man can do more than this." I remember when in
Good Success Bay, in Tierra del Fuego, thinking (and, I believe,
that I wrote home to the effect) that I could not employ my life
better than in adding a little to Natural Science. This I have
done to the best of my abilities, and critics may say what they
like, but they cannot destroy this conviction.

During the two last months of 1859 I was fully occupied in
preparing a second edition of the 'Origin,' and by an enormous
correspondence. On January 1st, 1860, I began arranging my notes
for my work on the 'Variation of Animals and Plants under
Domestication;' but it was not published until the beginning of
1868; the delay having been caused partly by frequent illnesses,
one of which lasted seven months, and partly by being tempted to
publish on other subjects which at the time interested me more.

On May 15th, 1862, my little book on the 'Fertilisation of
Orchids,' which cost me ten months' work, was published: most of
the facts had been slowly accumulated during several previous
years. During the summer of 1839, and, I believe, during the
previous summer, I was led to attend to the cross-fertilisation
of flowers by the aid of insects, from having come to the
conclusion in my speculations on the origin of species, that
crossing played an important part in keeping specific forms
constant. I attended to the subject more or less during every
subsequent summer; and my interest in it was greatly enhanced by
having procured and read in November 1841, through the advice of