bloodletting probably first came to be adopted as a remedial measure:—
Let us suppose that in the earliest period of man's history somebody
experienced the need of the medical art. He may, for
example, have felt a general sense of heaviness in his body
(plethora), associated perhaps with redness of the eyes, and he
probably did not know what he should do in order to obtain relief
from these sensations. Then, when his trouble was at its worst,
his nose began to bleed, and the bleeding continued until he
experienced decided relief from his discomfort. In this way he
learned an important fact, and cherished it in his memory.
On a later occasion he experienced once more the same sense of heaviness, and he lost no time in scratching the interior of his nose in order to provoke a return of the bleeding. The nose-*bleed thus excited again gave him entire relief from the unpleasant sensations, and upon the first convenient occasion he told his children and all his relatives about the successful results obtained from this curative procedure. Little by little this simple act, which was a first step in the healing art, developed into the intelligently and skilfully performed operation of venesection.
Primitive man also increased his stock of knowledge in
the healing art by reading attentively the book of nature,—i.e.,
by observing how animals, when ill, eat the leaves or
stems of certain plants and thus obtain relief from their
disorders. The virtues of a species of origanum, as an
antidote for poisoning from the bite of a snake, were
revealed, it is asserted, by the observation that turtles,
when bitten by one of these reptiles, immediately seek for
the plant in question and, after feeding upon it, experience
no perceptible ill effects from the poisonous bite. The
natives of India ascribe the discovery of the remarkable
virtues of snakeroot (the bitter root of the ophiorrhiza
Mungos) as an antidote for poisoning by the bite of a snake,
to the ichneumon, a small animal of the rat species. The
instinctive desire to escape pain taught man, as it does the
lower animals, to keep a fractured limb at rest, thus giving
the separated ends of the bone an opportunity to reunite;
after which the limb eventually becomes as strong as it
ever was. Simple as this mode of acquiring useful medical
