fferent quarters of the world, although all of them fertile
inter se, are in many cases obviously blood kin to the neighboring
wild, wolf-like or jackal-like creatures which are specifically, and
possibly even generically, distinct from one another. The big red wolf
of the South American plains is not closely related to the northern
wolves; and it was to me unexpected to find it interbreeding with
ordinary domestic dogs.

In the evenings after dinner we sat in the bare ranch dining-room, or
out under the trees in the hot darkness, and talked of many things:
natural history with the naturalists, and all kinds of other subjects
both with them and with our Brazilian friends. Colonel Rondon is not
simply "an officer and a gentleman" in the sense that is honorably
true of the best army officers in every good military service. He is
also a peculiarly hardy and competent explorer, a good field
naturalist and scientific man, a student and a philosopher. With him
the conversation ranged from jaguar-hunting and the perils of
exploration in the "Matto Grosso," the great wilderness, to Indian
anthropology, to the dangers of a purely materialistic industrial
civilization, and to Positivist morality. The colonel's Positivism was
in very fact to him a religion of humanity, a creed which bade him be
just and kindly and useful to his fellow men, to live his life
bravely, and no less bravely to face death, without reference to what
he believed, or did not believe, or to what the unknown hereafter
might hold for him.

The native hunters who accompanied us were swarthy men of mixed blood.
They were barefooted and scantily clad, and each carried a long,
clumsy spear and a keen machete, in the use of which he was an expert.
Now and then, in thick jungle, we had to cut out a path, and it was
interesting to see one of them, although cumbered by his unwieldy
spear, handling his half-broken little horse with complete ease while
he hacked at limbs and branches. Of the two ordinarily with us one was
much the younger; and whenever we came to an unusually doubtful-
looking ford or piece of boggy ground the elder man always sent the
younger one on and sat on the bank until he saw what befell the
experimenter. In that rather preposterous book of our youth, the
"Swiss Family Robinson," mention is made of a tame monkey called Nips,
which was used to test all edible-looking things as to the
healthfulness of which the adventurers felt doubtful; and beca