however, a reaction had begun, physicians were protected, and
dissections were occasionally sanctioned by the ruling monarch. Thus
Emperor Frederick H. (1194-1250 A.D.)--whose services to science we have
already had occasion to mention--ordered that at least one human body
should be dissected by physicians in his kingdom every five years. By
the time of Mondino dissections were becoming more frequent, and he
himself is known to have dissected and demonstrated several bodies. His
writings on anatomy have been called merely plagiarisms of Galen, but
in all probability be made many discoveries independently, and on
the whole, his 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 trephining for fracture o