it gave Roger Bacon, one
of the greatest benefactors of mankind, many years of imprisonment, and
nearly brought him to the stake: these cases are typical of very many.

Still another charge against physicians who showed a talent for
investigation was that of Mohammedanism and Averroism; and Petrarch
stigmatized Averroists as "men who deny Genesis and bark at
Christ."(307)

(307) For Averroes, see Renan, Averroes et l'Averroisme, Paris, 1861,
pp. 327-335. For a perfectly just statement of the only circumstances
which can justify a charge of atheism, see Rev. Dr. Deems, in Popular
Science Monthly, February, 1876.

The effect of this widespread ecclesiastical opposition was, that for
many centuries the study of medicine was relegated mainly to the lowest
order of practitioners. There was, indeed, one orthodox line of medical
evolution during the later Middle Ages: St. Thomas Aquinas insisted that
the forces of the body are independent of its physical organization,
and that therefore these forces are to be studied by the scholastic
philosophy and the theological method, instead of by researches into the
structure of the body; as a result of this, mingled with survivals of
various pagan superstitions, we have in anatomy and physiology such
doctrines as the increase and decrease of the brain with the phases
of the moon, the ebb and flow of human vitality with the tides of the
ocean, the use of the lungs to fan the heart, the function of the liver
as the seat of love, and that of the spleen as the centre of wit.

Closely connected with these methods of thought was the doctrine of
signatures. It was reasoned that the Almighty must have set his sign
upon the various means of curing disease which he has provided: hence
it was held that bloodroot, on account of its red juice, is good for the
blood; liverwort, having a leaf like the liver, cures diseases of the
liver; eyebright, being marked with a spot like an eye, cures diseases
of the eyes; celandine, having a yellow juice, cures jaundice; bugloss,
resembling a snake's head, cures snakebite; red flannel, looking like
blood, cures blood-taints, and therefore rheumatism; bear's grease,
being taken from an animal thickly covered with hair, is recommended to
persons fearing baldness.(308)

(308) For a summary of the superstitions which arose under the
theological doctrine of signatures, see Dr. Eccles's admirable little
tract on the Evolution of Medical Science,