apes, he was careful to lay great stress on the
important difference in size and weight. A full-grown gorilla is
nearly twice as heavy as a European woman, and yet the heaviest known
gorilla brain probably does not exceed twenty ounces in weight, while
healthy adult human brains probably never weigh less than thirty-one
or thirty-two ounces. This difference is not of systematic importance;
for cranial capacities shew that relatively and absolutely there is a
greater difference in brain-weight between the lowest and highest
human beings than there is between the highest ape and the lowest
human being.

In dealing with the suggestion that man differs from the apes in being
bimanous, while the apes are quadrumanous, Huxley first explained and
discussed what the exact differences between hands and feet are. He
shewed that in man the foot is absolutely distinguished from the hand
by three structural points, although the two organs are similar in
general ground-plan. These structural points are:

1. The arrangement of the tarsal bones.

2. The possession of a short flexor and short extensor muscle of the
digits.

3. The possession of a muscle named _peronaeus longus_.

Then he described the foot of the gorilla, and shewed that although it
was superficially hand-like, it possessed all the structural
characters that distinguish a foot from a hand. Tracing the structure
of the foot downwards through the series of anthropoids and monkeys,
he established clearly that, while important differences existed in
nearly every single creature, the differences between the gorilla and
man were not greater than those between the gorilla and other
anthropoids, and less than between the gorilla and lower monkeys.

This wonderful series of lectures ranks very high among the important
works of Huxley. It is true that a considerable proportion of the work
was not absolutely original, but it had all been specially verified by
him. It was a task undertaken with the greatest courage, and with a
care equal to the courage; and it settled conclusively for all time
the impossibility of making between man and the anthropoids any
anatomical barriers greater than those which exist between the
different although closely related members of any of the other family
groups in the animal kingdom. The advance of knowledge has only added
to the details of Huxley's argument; it has not made any
reconstruction of it necessary. A writer on the same subject to