living processes which
determined natural groups; the theories he formed needed verification
in various directions. These excursions from the primary line of
research were of great value in broadening the basis of his knowledge.
He also deliberately set aside the years 1854-60 as a period in which
to make himself master of the branches of science cognate to his own,
so that he should be ready for any special pursuits in any of them.
For he did not know what was to be his task after the work that had
fallen to him, not of his own choice, at the School of Mines. He was
to ground himself in each department by monographic work, and by
1860 might fairly look forward to fifteen or twenty years of
"Meisterjahre," when, with the comprehensive views arising from such
training, it should be possible to give a new and healthier direction
to all biological science. Meanwhile, opportunities must be seized at
the risk of a reputation for desultoriness.

But the irony of circumstances diverted much of his energy into yet
more diverse fields. When Sir Henry de la Beche first offered him the
posts of Palaeontologist and Lecturer on Natural History vacated by
Professor Forbes, he says:--

I refused the former point blank, and accepted the latter
only provisionally, telling Sir Henry that I did not care for
fossils, and that I should give up Natural History as soon as
I could get a physiological post. But I held the office
for thirty-one years, and a large part of my work has been
palaeontological.

Palaeontology was his business, and he became a Master in it also,
with the result that he forged himself a mighty weapon for use in the
struggle over the Origin of Species.

In one of his later Essays he compares the study of human physiology
to the Atlantic Ocean:--

Like the Atlantic between the Old and the New Worlds, its
waves wash the shores of the two worlds of matter and of mind;
its tributary streams flow from both; through its waters, as
yet unfurrowed by the keel of any Columbus, lies the road, if
such there be, from the one to the other; far away from that
North-West Passage of mere speculation in which so many brave
souls have been helplessly frozen up.

Such was the spirit in which, after his long day's work, he added to
his labours in physical science a search in another, and to his notion
a cognate province of thought and speculation. Many a sleepless night
in these