Parker, afterwards his assistant:--

His lectures were like his writings, luminously clear, without
the faintest disposition to descend to the level of his
audience; eloquent, but with no trace of the empty rhetoric
which so often does duty for that quality; full of a high
seriousness, but with no suspicion of pedantry; lightened by
an occasional epigram or flashes of caustic humour, but with
none of the small jocularity in which it is such a temptation
to a lecturer to indulge. As one listened to him one felt that
comparative anatomy was worthy of the devotion of a life, and
that to solve a morphological problem was as fine a thing
as to win a battle. He was an admirable draughtsman, and his
blackboard illustrations were always a great feature of his
lectures, especially when, to show the relation of two animal
types, he would, by a few rapid strokes and smudges, evolve
the one into the other before our eyes. He seemed to have
a real affection for some of the specimens illustrating his
lectures, and would handle them in a peculiarly loving manner.
When he was lecturing on man, for instance, he would sometimes
throw his arm over the shoulder of the skeleton beside him
and take its hand, as if its silent companionship were an
inspiration. To me, his lectures before his small class at
Jermyn Street or South Kensington were almost more impressive
than the discourses at the Royal Institution, where, for
an hour and a-half, he poured forth a stream of dignified,
earnest, sincere words in perfect literary form, and without
the assistance of a note.

It was no wonder that he was clear and exact in his class lectures,