(or _per saltum_), the influence of environment, the question
of the inheritance of acquired characters and similar problems were
constantly present to Darwin's ever open mind, his views upon them
changing from time to time, as fresh facts were gathered.

No one could sympathise more fully than would Darwin, were he still with
us, in these various departures. He was compelled, from want of
evidence, to regard variations as spontaneous, but would have heartily
welcomed every attempt to discover the laws which govern them; and
equally would he have delighted in researches directed to the
investigation of the determining factors, controlling conditions and
limits of inheritance. The man who so carefully counted and weighed his
seeds in botanical experiments, could not but rejoice in the refined
mathematical methods now being applied to biological problems.

Let us not 'in looking at the trees, lose sight of the wood.' Underlying
all the problems, some of them very hotly discussed at the present day,
there is the great central principle of Natural Selection--which if not
the sole factor in evolution, is undoubtedly a very important and potent
one. It is only necessary to compare the present position of the Natural
History sciences with that which existed immediately before the
publication of the _Origin of Species_, to realise the greatness of
Darwin's achievement.

The fame of both Lyell and Darwin will endure, and their names will
remain as closely linked as were the two men in their lives, the two
devoted friends, whose remains found a meet resting-place, almost side
by side, in the Abbey of Westminster. Very touching indeed was it to
witness the marks of affection between these two great men; an affection
which remained undiminished to the end. Lyell was twelve years senior to
Darwin, and died seven years before his friend. During the last year of
Lyell's life, I spent the summer with him at his home in Forfarshire.
How well do I recollect the keenness with which--in spite of a
near-sightedness that had increased with age almost to blindness--he
still devoted himself to geological work. The 264 note-books, all
carefully indexed, were in constant use, and visits were made to all the
haunts of his youth, with the frequent pathetic appeal to me, 'You must
lend me your eyes.' In spite of age and weakness, he would insist on
clambering up the steepest hills to show me where he had found glacial
markings, and would eagerly