how much more dreadful must it have seemed to deal with the embryonic
body still enclosed in the womb, which the Creator himself had
decently veiled from the curiosity of the scientist! The Christian
Church, then putting many thousands to death for unbelief, had a
shrewd presentiment of the menace that science contained against its
authority. It was powerful enough to see that its rival did not grow
too quickly.

It was not until the Reformation broke the power of the Church, and a
refreshing breath of the spirit dissolved the icy chains that bound
science, that anatomy and embryology, and all the other branches of
research, could begin to advance once more. However, embryology lagged
far behind anatomy. The first works on embryology appear at the
beginning of the sixteenth century. The Italian anatomist, Fabricius
ab Aquapendente, a professor at Padua, opened the advance. In his two
books (De formato foetu, 1600, and De formatione foetus, 1604) he
published the older illustrations and descriptions of the embryos of
man and other mammals, and of the hen. Similar imperfect illustrations
were given by Spigelius (De formato foetu, 1631), and by Needham
(1667) and his more famous compatriot, Harvey (1652), who discovered
the circulation of the blood in the animal body and formulated the
important principle, Omne vivum ex vivo (all life comes from
pre-existing life). The Dutch scientist, Swammerdam, published in his
Bible of Nature the earliest observations on the embryology of the
frog and the division of its egg-yelk. But the most important
embryological studies in the sixteenth century were those of the
famous Italian, Marcello Malpighi, of Bologna, who led the way both in
zoology and botany. His treatises, De formatione pulli and De ovo
incubato (1687), contain the first consistent description of the
development of the chick in the fertilised egg.