WILLIAM HARVEY, M. D. 49 



formed embryo in the egg that needed only a slight stimulus 

 to make it grow and develop." In contrast the authors cite the 

 modern scientist who through " the employment of the scien- 

 tific method of repeated and careful observations and deduc- 

 tions has made it clear to us that the embryo is not preformed 

 in its final form. . ." but that " the various parts of the new 

 individual are gradually formed and undergo a tremendous 

 modification from their first appearance up to their final 

 state." " 



These same authors could have equally and more accurately 

 written: Over 2300 years ago, Aristotle, by employing the 

 scientific method of repeated careful observation as his basis 

 for inference, made it clear to anybody and everybody who 

 would read, that the preformationist account of embryological 

 development was impossible and the epigenetic account neces- 

 sary. He asked, " How, then, does it [the embryo] make the 

 other parts.f^ "; he answered, " Either all the parts, as heart, 

 lung, liver, eyes and all the rest, come into being together or in 

 succession . . ." " That the former is not the fact is plain even 

 to the sense, for some of the parts are clearly visible as already 

 existing in the embryo while others are not; that it is not be- 

 cause of their being too small that they are not visible is clear, 

 for the lung is of greater size than the heart, and yet appears 

 later than the heart in the original development " (734 a 17 ff .) . 

 William Harvey, 2000 years later, who did read, came out with 

 experimental confirmation and enrichment of the same view. 

 He states in his Generation of Animals: 



Now it appears clearly from my research that the generation of the 

 chick from the egg is the result of epigenesis (Exercise 45) . And 

 first, since it is certain that the chick is produced by epigenesis, i. e. 

 the addition of parts successively, we shall investigate what part 

 may be observed before any of the rest are erected, and what may 

 be observed in this mode of generation. What Aristotle says of 

 generation ... is confirmed and made manifest by all that passes 

 in the egg, viz. that all the parts are not made simultaneously, but 



^* S]jllabus, Introductory General Course in the Biological Sciences, edited by 

 Merle C. Coulter. Seventh edition. (University of Chicago, 1937), p. 104. 



