ent
points of the structure of the Toxodon!" All forms of life attracted
him. He looked into the brine-pans of Lymington and found that water
with one quarter of a pound of salt to the pint was inhabited, and he
was led to say: "Well may we affirm that every part of the world is
habitable! Whether lakes of brine or those subterranean ones hidden
beneath volcanic mountains,--warm mineral springs,--the wide expanse
and depth of the ocean,--the upper regions of the atmosphere, and even
the surface of perpetual snow,--all support organic beings."

He studies the parasitical habit of the cuckoo and hits on an
explanation of it. He speculates why the partridges and deer in South
America are so tame.

His "Voyage of the Beagle" alone would insure him lasting fame. It is
a classic among scientific books of travel. Here is a traveler of a
new kind: a natural-history voyager, a man bent on seeing and taking
note of everything going on in nature about him, in the non-human, as
well as in the human world. The minuteness of his observation and the
significance of its subject-matter are a lesson to all observers.
Darwin's interests are so varied and genuine. One sees in this volume
the seed-bed of much of his subsequent work. He was quite a young man
(twenty-four) when he made this voyage; he was ill more than half the
time; he was as yet only an observer and appreciator of Nature, quite
free from any theories about her ways and methods. He says that this
was by far the most important event of his life and determined his
whole career. His theory of descent was already latent in his mind, as
is evinced by an observation he made about the relationship in South
America between the extinct and the living forms. "This relationship,"
he said, "will, I do not doubt, hereafter throw more light on the
appearance of organic beings on our earth, and their disappearance
from it, than any other class of facts."

He looked into the muddy waters of the sea off the coast of Chile, and
found a curious new form of minute life--microscopic animals that
exploded as they swam through the water. In South America he saw an
intimate relationship between the extinct species of ant-eaters,
armadillos, tapirs, peccaries, guanacos, opossums, and so on, and the
living species of these animals; and he adds that the wonderful
relationship in the same continent between the dead and the living
would doubtless hereafter throw more light on the appearance of
organ