for he based what he had to say on his own experiment and observation,
and was at pains to verify experimentally the observations of others
which came within his field. Without verification he would not rely
upon them. Indeed, he was so careful to give nothing at second hand
that one of his scientific friends gently reproached him for wasting
his time in re-investigating matters already worked over by competent
observers. "Poor ----," he remarked afterwards, "if that is his own
practice, his work will never live." Of his most important public
addresses, two may be noted as especial _tours de force_. On each
occasion it was specially necessary to speak by the book, but at the
last moment it was impossible to use the carefully prepared notes. One
was the address on the complex and difficult subject of "Animals as
Automata," at the Belfast meeting of the British Association in 1874,
when the atmosphere was electrical after a Presidential address by
John Tyndall which set theologians in an uproar. Years afterwards he
described the incident to Sir E. Ray Lankester:--

I knew that I was treading on very dangerous ground, so I
wrote out uncommonly full and careful notes, and had them in
my hand when I stepped on to the platform.

Then I suddenly became aware of the bigness of the audience,
and the conviction came upon me that, if I looked at my notes,
not one half would hear me. It was a bad ten seconds, but I
made my election and turned the notes face downwards on the
desk.

To this day I do not exactly know how the thing managed to
roll itself out; but it did, as you say, for the best part of
an hour and a-half.