Editor's Introduction xxi 



It contains a great number of acute and interesting 

 observations; and he had evidently made many more, 

 for he says that his papers on the Generation of 

 Insects were lost as a result of the tumults which 

 arose at the outbreak of the Civil War. He told 

 Aubrey that no grief was so crucifying to him as the 

 loss of these papers. The King took a direct personal 

 interest in these investigations, 1 and supplied him with 

 deer from the Royal Parks in order to further them. 



In two respects the work on Generation is worthy 

 of more than a mere passing notice, and entitles its 

 author to the possession of almost prophetic genius. 

 The first is the enunciation of the great generalisation 

 omne vivum ex ovo. Although this particular phrase 

 is nowhere to be found, as is often erroneously stated, 

 in the treatise on Generation, yet a perusal of Exer- 

 cises I., LI., and LXII. will convince any one that 

 Harvey had grasped this great idea, which has since 

 been so abundantly verified. The other is his doctrine 

 of Epigenesis, or the formation of the new organism 

 from the homogeneous substance of the germ by the 

 successive differentiation of parts, that all parts are 

 not formed at once and together, but in succession 

 one after the other. He put forward this doctrine of 

 Epigenesis in contradistinction to that of Metamorphosis, 

 according to which the germ was suddenly transformed 

 into a miniature of the whole organism which subse- 

 quently grew. This is certainly very remarkable, and 

 entitles him to be regarded as a forerunner of Caspar 

 Wolff, Von Baer, and the modern Evolutionary School, 

 which sees in the development of the organism from 

 the ovum a passage from the homogeneous to the 

 heterogeneous by a gradual process of differentiation, 

 from a germ in which there is no sign of any of the 

 parts of the adult to an organism with all its many 

 and varied organs. Commenting on certain passages 

 cf Exercise XLV., in which Harvey specially refers 



1 De Generatione Ex. Ixix. 



