Lawrence, one of the ablest men whom I have known, had been well-nigh
ostracised for his book "On Man," which now might be read in a Sunday
school without surprising anybody; it was only a few years since the
electors to the chair of Natural History in a famous northern university
had refused to invite a very distinguished man to occupy it because he
advocated the doctrine of the diversity of species of mankind, or what
was called "polygeny." Even among those who considered man from the
point of view, not of vulgar prejudice, but of science, opinions lay
poles asunder. Linnaeus had taken one view, Cuvier another; and among my
senior contemporaries, men like Lyell, regarded by many as
revolutionaries of the deepest dye, were strongly opposed to anything
which tended to break down the barrier between man and the rest of the
animal world.

My own mind was by no means definitely made up about this matter when,
in the year 1857, a paper was read before the Linnean Society "On the
Characters, Principles of Division and Primary Groups of the Class
Mammalia," in which certain anatomical features of the brain were said
to be "peculiar to the genus 'Homo,'" and were made the chief ground for
separating that genus from all other mammals and placing him in a
division, "Archencephala," apart from, and superior to, all the rest. As
these statements did not agree with the opinions I had formed, I set to
work to reinvestigate the subject; and soon satisfied myself that the
structures in question were not peculiar to Man, but were shared by him
with all the higher and many of the lower apes. I embarked in no public
discussion of these matters, but my attention being thus drawn to them,
I studied the whole question of the structural relations of Man to the
next lower existing forms, with much care. And, of course, I embodied my
conclusions in my teaching.