3
In order that we may the better understand
Harvey's position when he commenced those
studies of which the ultimate fruit was his cele-
brated treatise on Generation-it is desirable to
bear in mind the prevalent physiological doctrines
of that day. Harvey found the teachers of this
branch of physiology divided into two. principal
parties. According to the teaching of Aristotle,
the principles of generation were the male and
the female, she contributing the matter, he the
form; and immediately after conception the vital
principle, and the first particle of the future
foetus-namely, the heart, in animals having red
blood-were formed from the menstrual blood in
the uterus. On the other hand, the followers of
Galen, with whom were the physicians, taught
that the semen of both parents combined fur-
nished the offspring, which resembled one or
other according as this or that predominated, and
that by virtue of such predominance it became
either male or female.
Neither of these doctrines, however, gave satis-
faction to Harvey, but the contrary. "That they
are erroneous and hasty conclusions,' he says, 'is
easily made to appear: like phantoms of darkness,
