The Descent of Man

have some few instincts in common. All have
the same senses, intuitions, and sensations,—
similar passions, affections, and emotions, even
the more complex ones, such as jealousy, suspicion,
emulation, gratitude, and magnanimity;
they practise deceit and are revengeful; they are
sometimes susceptible to ridicule, and even
have a sense of humour; they feel wonder and
curiosity; they possess the same faculties of
imitation, attention, deliberation, choice, memory,
imagination, the association of ideas, and
reason, though in very different degrees. The
individuals of the same species graduate in
intellect from absolute imbecility to high excellence.
They are also liable to insanity, though
far less often than in the case of man. (30. See
'Madness in Animals,' by Dr. W. Lauder Lindsay,
in 'Journal of Mental Science,' July 1871.)
Nevertheless, many authors have insisted that
man is divided by an insuperable barrier from
all the lower animals in his mental faculties. I
formerly made a collection of above a score of