THE RISE OF EMBRYOLOGY 199 
By clearly teaching, on the basis of his own observations, 
the gradual formation of the body by aggregation of its parts, 
he anticipated Wolff. This doctrine came to be known under 
the title of “‘epigenesis,” but Harvey’s epigenesis* was not, 
as Wolfl’s was, directed against a theory of pre-delineation of 
the parts of the embryo, but against the ideas of the medical 
men of the time regarding the metamorphosis of germinal 
elements. It lacked, therefore, the dramatic setting which 
surrounded the work of Wolff in the next century. Had the 
doctrine of pre-formation been current in Harvey’s time, we 
are quite justified in assuming that he would have assailed it 
as vigorously as did Wolff. 
His Treatise on Generation.—Harvey’s embryological 
work was published in 1651 under the title Evercitationes de 
Generatione Animalium. It embraces not only observations 
on the development of the chick, but also on the deer and some 
othermammals. Ashe was the court physician of Charles I, 
that sovereign had many deer killed in the park, at intervals, 
in order to give Harvey the opportunity to study their devel- 
opment. 
As fruits of his observation on the chick, he showed the 
position in which the embryo arises within the egg, v7z., in 
the white opaque spot or cicatricula; and he also corrected 
Aristotle, Fabricius, and his other predecessors in many par- 
ticulars. 
Harvey’s greatest predecessor in this field, Fabricius, was 
also his teacher. When, in search of the best training in 
medicine, Harvey took his way from England to Italy, as 
already recounted, he came under the instruction of Fa- 
bricius in Padua. Jn 1600, Fabricius published sketches 
showing the development of animals; and, again, in 1625, 
six years after his death, appearcd his illustrated treatise on 
* As Whitman has pointed out, Aristotle taught epigenesis as clearly as 
Harvey, and is, therefore, to he regarded as the founder of that conception. 
