work may be taken as more advanced than Galen's. His description
of the heart is particularly accurate, and he seems to have come
nearer to determining the course of the blood in its circulation
than any of his predecessors. In this quest he was greatly
handicapped by the prevailing belief in the idea that
blood-vessels must contain air as well as blood, and this led him
to assume that one of the cavities of the heart contained
"spirits," or air. It is probable, however, that his accurate
observations, so far as they went, were helpful stepping-stones
to Harvey in his discovery of the circulation.

Guy of Chauliac, whose innovations in surgery reestablished that
science on a firm basis, was not only one of the most cultured,
but also the most practical surgeon of his time. He had great
reverence for the works of Galen, Albucasis, and others of his
noted predecessors; but this reverence did not blind him to their
mistakes nor prevent him from using rational methods of treatment
far in advance of theirs. His practicality is shown in some of
his simple but useful inventions for the sick-room, such as the
device of a rope, suspended from the ceiling over the bed, by
which a patient may move himself about more easily; and in some
of his improvements in surgical dressings, such as stiffening
bandages by dipping them in the white of an egg so that they are
held firmly. He treated broken limbs in the suspended cradle
still in use, and introduced the method of making "traction" on a
broken limb by means of a weight and pulley, to prevent deformity
through shortening of the member. He was one of the first
physicians to recognize the utility of spectacles, and
recommended them in cases not amenable to treatment with lotions
and eye-waters. In some of his surgical operations, such as