of Thomas Henry
Huxley", London, 1900, I. page 457), the facts of the old teleology are
immediately transferable to Darwinism, which simply supplies them with a
natural in place of a supernatural explanation.") Burchell here seems
to miss, at least in part, the meaning of the relationship between the
quiescence of the Acridian and its cryptic colouring. Quiescence is an
essential element in the protective resemblance to a stone--probably
even more indispensable than the details of the form and colouring.
Although Burchell appears to overlook this point he fully recognised the
community between protection by concealment and more aggressive modes
of defence; for, in the passage of which a part is quoted above, he
specially refers to some earlier remarks on page 226 of his Vol. I. We
here find that even when the oxen were resting by the Juk rivier (Yoke
river), on July 19, 1811, Burchell observed "Geranium spinosum, with
a fleshy stem and large white flowers...; and a succulent species of
Pelargonium... so defended by the old panicles, grown to hard woody
thorns, that no cattle could browze upon it." He goes on to say, "In
this arid country, where every juicy vegetable would soon be eaten up by
the wild animals, the Great Creating Power, with all-provident wisdom,
has given to such plants either an acrid or poisonous juice, or sharp
thorns, to preserve the species from annihilation... " All these modes
of defence, especially adapted to a desert environment, have since
been generally recognised, and it is very interesting to place beside
Burchell's statement the following passage from a letter written by
Darwin, Aug. 7, 1868, to G.H. Lewes; "That Natural Selection would tend
to produce the most formidable thorns will be admitted by every one
who has observed the distribution in South America and Africa (vide
Livingstone) of thorn-bearing plants, for they always appear where the
bushes grow isolated and are exposed to the attacks of mammals. Even
in England it has been noticed that all spine-bearing and sting-bearing
plants are palatable to quadrupeds, when the thorns are crushed." ("More
Letters", I. page 308.)

ADAPTATION AND NATURAL SELECTION.

I have preferred to show the influence of the older teleology upon
Natural History by quotations from a single great and insufficiently
appreciated naturalist. It might have been seen equally well in the
pages of Kirby and Spence and those of many other writers. If the older
natu