Problems, Concepts and Their History 



generation of Animals is diverse likewise" 

 {ibid., p. 384), and while he considered 

 some animals to be "perfected by a succes- 

 sion of parts'' {ibid., p. 344), he knew others 

 to be "made intire at once" {loc. cit.), 

 "formed and transfigured, out of matter al- 

 ready concocted and grown" {ibid., p. 222). 

 "The form ariseth ex potentid materiae prae- 

 existentis, out of the power or potentiality of 

 the pre-existent matter; and the matter is 

 rather the first cause of the Generation, then 

 any external Efficient" {ibid., p. 223). 



This resounds strongly of preformation- 

 ism, and indeed in the modern rather than 

 the old-fashioned sense. There are those who 

 claim that Harvey's work on generation was 

 of little historical moment because of its rela- 

 tive obscurity at the time of its publication. 

 Malpighi, however, knew it, and he knew 

 because of it to start his studies with the 

 blastoderm; indeed, Harvey is mentioned on 

 the first page of Malpighi's text, a notation 

 which may bear witness to the fact that the 

 ideas of preformation may themselves have 

 been fostered at least in part by the inade- 

 quacies of the early epigenetic postulate. 



EMBRYOLOGY AND THE NEW MICROSCOPE: 



PREFORMATION AND MALPIGHI; 



EPIGENESIS AND WOLFF 



Harvey's failure which drove him back to 

 the metaphysics from which he started we 

 have called a physical one related to the 

 inadequacy of his senses. Malpighi here had 

 the advantage over him, with the use of the 

 microscope as a new tool, and with it he 

 overstepped the old limitations to enter what 

 might seem in some ways a new conceptual 

 realm, namely that of preformationism. 



This doctrine of preformation, however, 

 was no clear and strong new reply to an old 

 question by a new science. It was a principle 

 deeply intrenched in ancient philosophy and 

 destined to outlast for many years the valid- 

 ity of the scientific evidence once seeming 

 to favor it. It remained, indeed, a philosoph- 

 ical dogma rather than a scientific principle 

 even after long being discussed on a scien- 

 tific basis: its most ardent biological cham- 

 pion. Bonnet, was to betray the preponder- 

 ance of its philosophical over its scientific 

 weight by calling it "one of the greatest 

 triumphs of rational over sensual conviction" 

 (cited by Needham, '34, p. 191). 



The concept roots, on the philosophical 

 side, at least as remotely into antiquity as 

 the times of Leucippus and Democritus, 

 whom Aristotle so strongly opposed, and the 



implications of preformation inherent in the 

 ancient materialistic doctrines were clearly 

 realized by Lucretius {De rerum natura, 

 Bk. I, lines 159-214). Seneca wrote as early 

 as the first century (cited by Needham, '34, 

 p. 48): 



In the seed are enclosed all the parts of the body 

 of the man that shall be formed. The infant that is 

 borne in his mother's wombe hath the rootes of the 

 beard and hair that he shall weare one day. In thif 

 little masse likewise are all the lineaments of the 

 bodie and all that which Posterity shall discover in 

 him. 



When the formed element is present ab 

 initio, the end and the beginning are the 

 same, and the principle of emboitement be- 

 comes difficult to escape. It too was recog- 

 nized early; a theory of emboitement ex- 

 pressed by Saint Augustine is quoted by 

 Wheeler (1898). Nearer to the time of Mal- 

 pighi (for the early and intervening develop- 

 ment of the concepts see Cole, '30; Meyer, 

 '39; and Needham, '34), Joseph of Aroma- 

 tari (1625) reiterated an old idea of Empe- 

 dokles that the plant is present in the un- 

 germinated seed and said that "the chick is 

 formed before the hen broods upon it" 

 (Meyer, '39, p. 63). 



It was Malpighi, however, who in 1673 re- 

 ported the observations which were to endow 

 the theory with new vigor. He studied with 

 the new microscope what he thought to be the 

 unincubated egg, to see in its blastoderm the 

 structures so magnificently portrayed in 

 the familiar plates, and to interpret them 

 to signify that the parts of the animal may 

 pre-exist in the egg. He indulged in less 

 dogmatism in his claims, however, than pos- 

 terity customarily attributes to him, as is 

 emphasized in analysis of his work by Adel- 

 mann currently in progress. Malpighi or- 

 ganized no formal and systematic theory of 

 development; he did not himself use the 

 word preformation, and there is some ques- 

 tion, according to Adelmann, as to what he 

 meant by the pre-existence of the animal in 

 the egg. He expressed his notions only ten- 

 tatively, and he was, in fact, uncertain 

 whether new structures existed before he 

 observed them: "Nam primum ortum non 

 assequuti, emergentem successive partium 

 manifestionem expectare cogimur" (1685 

 edition, p. 577). In sum, according to Adel- 

 mann's interpretation, he can justly be 

 called a preformationist only with consider- 

 able qualification. 



As Maitre-Jan was to point out and ex- 

 plain in 1722, the egg examined by Mal- 

 pighi was not what he had considered it — an 



