THE RISE OF EMBRYOLOGY IQQ 



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 Wolff'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 timic, we 

 are quite justified in assuming that he would have assailed it 

 as vigorously as did Wolff. 



His Treatise on Generation. — Harv^ey's embryological 

 work was published in 165 1 under the title Exercitationes de 

 Generatione Animalium. It embraces not only observations 

 on the development of the chick, but also on the deer and some 

 other mammals. As he 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 \\ithin the egg, viz., 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. In 160c, Fabricius published sketches 

 showing the development of animals; and, again, in 1625, 

 six years after his death, appeared his illustrated treatise on 



* As Whitman has pointed out, Aristotle taught epigenesis as clearly as 

 Harvey, and is, therefore, to be regarded as the founder of that conception. 



