Advanced search
Publication Cover
Annals of Science Volume 25, 1969 - Issue 2
Submit an article Journal homepage
85
Views
7
CrossRef citations to date
0
Altmetric
Original Articles

Harvey: Spontaneous generation and the egg

Edward T. Foote S.J.A.M.Ph.D.View further author information
Pages 139-163 | Published online: 22 Aug 2006

  • There were four 1651 printings of the book, all in Latin, according to Keynes A Bibliography of the Writings of William Harvey, M.D. Cambridge 1928 English versions include that of the 1653 attributed to Lluelyn; that of 1847 by Willis, The Works of William Harvey, M.D., New York, 1847; the excerpts translated for A. W. Meyer, An Analysis of the De Generatione Animalium of William Harvey, Stanford, 1936. To eliminate ambiguities which are artifacts in translation, this study relies upon the Latin text in the 1766 Opera Omnia, edited by Mark Akenside, M.D.: Guilielmi Harveii Opera Omnia a Collegio Medicorum Londinensi Edita, London, 1766, which presents, pp. 159–603, ‘Exercitationes de Generatione Animalium’. Harvey's book consists of a Preface and of seventy-two numbered, and several unnumbered, Exercitationes, each a rather integrated unit of discussion. At times the material of one Exercitatio overlaps or repeats matter of others—with the ‘labyrinthine’ results noted by Willis, op. cit., p. lxix.
  • The term ‘a-biogenesis’, throughout this paper, has its present-day meaning. Harvey does not use the word. See Part III Ex. 29 304 304 (plants, not from seed); Ex. 38/323; Ex. 41/337; Ex. 45/350; Ex. 50/386; Ex. 57/446; Ex. 62/476; Ex. ‘On Parturition’/548; Ex. ‘On Uterine Membranes’/573. Loci seemingly referring to a-biogenesis, but not so expressly, are: Ex. 1/182; Ex. 18/264, 265; Ex. 27/297.
  • Huxley , T.H. 1878 . Scientific Worthies: XII William Harvey… . Nature , 17 : 418 – 418 .
  • For example Pagel W. William Harvey's Biological Ideas New York 1967 ‘[Harvey's] idea of the ovoid “primordium” … implied some doubt on spontaneous generation’ (p. 329; cf. p. 335). Or, H. P. Bayon, ‘William Harvey (1578–1657), His Application on Biological Experiment …’, Journal of the History of Medicine and Allied Sciences, 1947, vol. 2: ‘If Harvey really believed Ex ovo omnia then he could not admit that shapeless mud or putrefying matter could generate living animals and, what is more unreasonable, accept their origin and development by a process of epigenesis’ (p. 63; cf. p. 64). Some of the confusion seems occasioned by commentators' imposing non-Harvean meanings on one or another of his terms, such as ‘ovum’, ‘spontaneous generation’, ‘equivocal generation’ or even ‘epigenesis’ (as differentiated from metamorphosis). See, for example, Adelmann, The Embryological Treatises of Hieronymus Fabricius of Aquapendente, ed. H. B. Adelmann, New York, 1942, p. 116; J. Needham, A History of Embryology, Cambridge, 1934, p. 129; F. J. Cole, Early Theories of Sexual Generation, Oxford, 1930, pp. 141, 142; R. Virchow, ‘The Liberty of Science in the Modern State’, Popular Science Monthly (Supplement), 1878, p. 302.
  • One reason why the septuagenarian Harvey was reluctant to give his MSS. to Dr George Ent for publication was their incompleteness regarding insect generation Opera 1766 163 163 164. Harvey says his notes resulting from years of his work on insects were taken from his residence during the political upheavals [of 1642–44] (p. 502). See foot-note 55, below.
  • See, for example Hall A.R. The Scientific Revolution, 1500–1800 London 1954 143 149 154–158; Needham, op. cit., p. 128; A. C. Crombie, Augustine to Galileo—The History of Science A.D. 400–1650, London, 1952, p. 329: To Harvey ‘the revolution in physiology was chiefly due’.
  • The motto appeared at the beginning of two of the 1651 prints of the book, but not verbatim in the text of De Generatione. Cole (1930) Hall A.R. The Scientific Revolution, 1500–1800 London 1954 137 137 summarizes early references to Harvey's aphorism
  • From his Exercitatio Membranes of the Uterus Opera … 1766 573 573 574. Note: all translations are the present writer's. Parentheses () are Harvey's. Words or phrases enclosed in brackets [] have been added for clarification. Italics have been added for emphasis, etc.
  • 1766 . Membranes of the Uterus . Exercitatio , 63 : 485 – 485 . Also: ‘An [avian] ovum is an exposed conceptus from which the chick develops. A conceptus is an ovum remaining inside until its fetus has attained due completion. But the two agree in that they are vegetal primordia and are potentially the animals’ (op. cit., p. 482). ‘Let us designate this as the vegetative primordium: namely, the material [substantia corporea] which has a life potentially: or, something existing as an individual [per se existens] which is suited to change into a vegetating form-through a self contained principle’ (op. cit., p. 477).
  • This reference means Exercitatio 62 found on p. 477 of the 1766 Opera Omnia. Note that here, Harvey rejects Aristotle's way of distinguishing between an ovum and a scolex [vermiculus], and classifies both as ova. See the classification of ova, cited below, foot-note 36. Spiders apparently remained grouped with the insects until Linnaeus. Note also that Harvey, generically applies ‘primordium’ to many antecedents of the offspring—a papula in a hen's ovary, a fertilized egg, a conceptus, the first embryo particle, or an insect egg, larva, or pupa. Only a vegetative primordium with the ‘capacity’ to develop the new animal is a ‘true ovum’. See foot-note 25, below. Pagel, op. cit., p. 273, has the curious remark that Harvey ‘believed in primordia’. Here and elsewhere, pp. 274, 329, 335, Pagel seems to give to the term ‘primordium’ a meaning which is more restricted than Harvey's.
  • Harvey had traced fowls' eggs back to ovarian ‘papulae’, ‘finer than millet’, and had similar information about other ovipara, fish, cephalopods, etc. Ex. 3 188 188 Ex. 50. He compares fertilized and unfertilized avian eggs in great detail; he mentions non-prolific insect eggs. He had no evidence which convinced him that any paternal material (seminal fluid) ever combined with eggs, or with any female ‘geniture’ (cf. foot-note 35, below). Milt, he thought, merely contacted fish-eggs and ‘acted upon’ them (Ex. 49). He did not theorize that the mammalian ovary (female ‘testis’) produced any ‘geniture’ (‘female semen’) which would then enter into a fertilization process. ‘Genitures’ were his nearest approach to gametes as we know them; preformation and emboitement are foreign to his thought; an ovism (as opposed to an animalculism) of course would have meaning only later, after cells were in view.
  • The egg before the first (sanguino-cardiac) particle, the conceptus ‘before anything of the embryo is discerned’, and the pupa while still a homogeneous fluid, are homologous, he thought. Bayon William Harvey (1578–1657), His Application on Biological Experiment … Journal of the History of Medicine and Allied Sciences 1947 2 70 73 has an informative discussion concerning the effect on Harvey of the particular dissection material he used. Harvey found eggs cheap (Ex. 63/482); his Majesty King Charles supplied the deer for dissection (Ex. 64). Cf. Ex. ‘Uterine Membranes’/574; Preface/179.
  • Lacking data on the ovum as a gamete, on the zygote, on the trophoblast, on implantation, etc., Harvey saw the mammalian conceptus as preceding and producing the first (sanguino-vascular) particle of the embryo from the amniotic fluid. He refers to this initial embryo many times, e.g. Ex. 17 252 252 253; Ex. 47/363, 364; Ex. 51/392; Ex. 72/534, 535
  • ‘We assert that absolutely all animals—including the viviparous and man himself—are produced from an ovum. Their initial conceptus out of which the fetus originates is some sort of ovum, as is also the seed of every plant’ Ex. 1 182 182 cf. Ex. 56/433; Ex. 57/446 cited in foot-note 37, below; Ex. 62/477; Ex. 63/483. The limitation any ‘modern’ would put on Harvey's generalization was pointed out by Rudolf Virchow, op. cit., p. 302: ‘We date the beginning of our real knowledge of the development of higher organisms from the day when Harvey uttered the famous proposition, Omne vivum ex ovo. This … as we now know … was as a general proposition inexact…. Later we became acquainted with a great number of new forms of propagation in sundry species of living beings—as direct segmentation, gemmation, and alternate generation…. Now we have no one formula to explain once for all how a new animal existence begins’.
  • Harvey quotes from the first page of Fabrizio's De Formatione Ovi Pennatorum: ‘“Animalium foetus, alius ex ovo, alius ex semine, alius ex putri gignitur; unde alia ovipara, alia vivipara, alia ex putri seu sponte naturae nascentia AUTOMATA Graece dicuntur.”’ Then he goes on: ‘Mihi vero haec divisio minus placet; cum omnia animalia dici possint quodam modo ex ovo, et quodam modo ex semine oriri; et a partu potius, quam a prima origine, ovipara, vivipara sive vermipara dicantur; quoniam vel ovum, vel vermem, vel vivum animal pariunt. Item sponte nascentia dicuntur; non quod ex putredine oriunda sint; sed quod casu, naturae sponte, et aequivoca, ut aiunt, generatione, a parentibus sui dissimillibus proveniant….’ Ex. 1 182 182 Note that Harvey here does not state that ex putredine generation is a fact, and that he does not say that it is the same as ‘spontaneous’ generation. Harvey's reasons for preferring to group larvae with eggs and classify all animals in two groups (viviparous or oviparous) are discussed in Ex. 62. See foot-note 10, above, and foot-note 36, below.
  • ‘Wind egg’: simply a non-fertile egg—called hypenemic, subventitious, zepherine, etc. Harvey made a clear distinction between stimuli for ovulation (the result of which might be a ‘wind egg’) and the ‘fecundating influence’ of insemination (which would condition the female to form fertile eggs) Ex. 13 232 232 233, 236; Ex. 47/362, 363; Ex. 5/198, 202; Ex. 6/204. Cf. foot-note 40, below. The ‘wind egg’ is an organism, living for a time; Ex. 26/290; Ex. 29/305.
  • ‘Foemina a mare foecunda reddita foetum postea sua spontei generat’ Ex. 51 388 388 Harvey also describes as ‘spontaneous’ the production of plant-seed, of the fish-egg, etc. Cf. Ex. 38/323; Ex. 40/334; Ex. 51/388. The spawned fish-egg also swells sua sponte (Ex. 49/374).
  • In Ex. 45 350 350 he contrasts insects with the ‘perfectiora … sanguinea’ generated ‘ab univoco principio (nempe ab eadem specie)’. He says that ‘Nature’, or whatever one wants to call the remote general agency in generation, procreates some animals ‘aequivoce … quaedam autem non nisi univoce generat’ (Ex. 39/324). Cf. foot-notes 32, 37, 44; Ex. 57/449; and Ex. 50/386, cited in foot-note 43, below. Harvey's regard for the larva, almost as a ‘dissimilar parent’ of the chrysalis or true ovum and of the insect produced, might be appreciated nowadays by comparing the larva to the a-sexual phase in an alternation of generation cycle. Cf. foot-note 29, below.
  • Species-formula’ used here to designate Harvey's chiefly descriptive but also heuristic construct of ‘some sort of dynamic process’ carried along in material, a physical condition in material rather than a material itself; it would account for the offspring's ‘mixed nature’ from both parents. Ex. 50 passim; Ex. ‘On Conception’/592, ff.; Ex. 57/447, 448; Ex. 29/304, 305; Ex. 46/359; Ex. 47/364. See foot-note 25, below. Currently we assign to genotype, the function which Harvey assigns to the ‘formula’ which determines the eventual phenotype. Harvey's terms for this ‘species-formula’ are: ratio, lex, species, forma.
  • Harvey suggests this order in studying all generation: Start with the offspring; then investigate the antecedent materials and the agencies immediately producing it; then go back to the materials and causes leading to that preceding stage; etc. Preface 177 177 178
  • There is an extended discussion of metamorphosis in Ex. 45 349 351 Cf. Ex. 57/445; Ex. 62/479. Swammerdam (1637–1680), a pioneer in applying microscopy to insects, flatly rejected metamorphosis in favour of preformation. In his book on insects (1669)—translated: Histoire Generale des Insectes (Autrecht, 1685)—he says that Harvey, ‘following the example of Aristotle … and an infinity of others’, had simply assumed this ‘imaginary’, ‘miraculous’, ‘chimerical’ transformation, and ‘without reason’ had called the pupa an ovum. The return of the larva to the homogeneous, ‘potential animal’ and subsequent metamorphosis (cf. foot-note 29, below) would be like a ‘death and resurrection’ (pp. 9, 10, 17, 30–34, 78 and passim). The larva and the pupa, says Swammerdam are actually the animal. A. R. Hall (op. cit., p. 291) has noted: ‘The effect of microscopy soon after Harvey's death, was to give immediate advantage to the … theory of preformation …’.
  • A resourceful and closely thought out theory on nutrition is an integral part of De Generatione. It is sketched in Ex. 27 Ex. 34/313; Ex. 53/413, 414; Ex. 60/469; Ex. 70/520; Ex. 72/535, 536. ‘Nourishing is quantitative and qualitative replacing of what was lost … substituting flesh or nerve for flesh or nerve broken down. What else is this than to make flesh or nerve?… To generate a chick is nothing else than to fabricate its particular parts, members, and organs …’ (Ex. 54/417). ‘… Nutrition [is] in fact a certain kind of generation’ (Ex. 71/531).
  • Ex. 45; Ex. 54; Ex. 71. Harvey has a clear—and for his time, penetrating—analysis of epigenesis. Epigenesis is not metamorphosis; and it is contradictory to preformation—which Harvey does not propose. Cf. Huxley's speech in: The Harvey Tercentenary Nature 1878 18 146 146 Bayon, op. cit., p. 78; and Needham, op. cit., pp. 129, 130. But Cole, op. cit., p. 39, seems to confuse epigenesis with preformation and also with the meaning of potentia; cf. foot-note 27, below.
  • Ex. , 45 350 – 350 . In the ‘suitably’ prepared, homogeneous material, somehow there is a ‘capacity’ or ‘power’. It is like the ‘fecundity’-factor which Harvey keeps trying to describe, in seminal fluid, in the maternal organism, in the uterus, in the conceptus, in the first particle of the embryo, etc. (Ex. 30/306). This factor is closely associated with the species-formula (see foot-note 19, above); it is not the material itself, nor the structuring of the material; it is not a kind of ghost or ‘demiurge’; and it is not the ‘internal efficient’, itself, which is mentioned next. Cf., e.g., Ex. 26/289; Ex. 38/323; Ex. 50/376, 387.
  • To such an ‘internal efficient (cause)’, Harvey ultimately traces the activation and control of organic processes. He calls this ultimate control-substance by the Aristotelean and scholastic term ‘soul’ [anima]. In a monograph—Foote, An Organism's “Soul” as Described by William Harvey, M.D. (Rome, 1964)—I have reported a study of constructs used in De Generatione. The findings submitted are that Harvey's anima is not an Aristotelean entelechy, certainly not the ‘substantial form’ of Aquinas, not the ‘vital principle’ of (decadent) sixteenth- and seventeenth-century Scholastic meta-science, nor any ‘incorporeal spirit’. His idea of ‘soul’ seems to function heuristically, rather than to dead-end his scientific enquiry—despite the ‘harness of Aristotle’ often quoted from Willis The Works of William Harvey, M.D. New York 1847 lxxi lxxi
  • Ex. ‘Membranes of the Uterus’/573. Cf. Ex. 62. In the first citation at the beginning of this paper, Harvey says ‘actually or potentially’. This is not a statement of preformation; it is an observation that the completed primordium has that (whatever it is) by which it would operate on its material and thus form the (full size) insect. Does Pagel William Harvey's Biological Ideas New York 1967 233 233 locate spontaneous generation at final metamorphosis?
  • See, e.g. Ex. 18 264 264 Harvey says that Aristotle describes … generation of the sponte nascentia: ‘“Some are produced from dew which falls upon leaves.” And a little further on: “Butterflies come into being out of caterpillars, and these from growing foliage … especially cabbage. At first there is [something] smaller than millet grain; then, tiny worms; after growing for three days, these are small caterpillars; then, when these have grown, they cease moving, change shape, and are enclosed in a hard shell. They are now referred to as chrysalides. If these are touched, they move. Finally, after a considerable period, the covering breaks open, and out of it flies the winged animal—the butterfly [Hist. An. V. 19]”.’ Ex. 62/478.
  • Ex. 62/479: ‘…respectu vero muscae, aut papilionis, cuius est potentia primordium, tanquam ovum repens et seipsum augens reputandum est’. And on the next page: ‘… ex ovis [the “first eggs”] vermes atque erucae [the larvae] primum erumpant, e quibus postea in chrysalidas sive aurelias, tanquam in nova ova [the “true eggs”], denuo regressis, musca tandem vel papilio enascitur’. Harvey was no innovator in describing a cycle in insects. Appealing to Aristotle, Fabrizio presents the butterfly cycle in his De Formatione Ovi Pennatorum, p. 49 (cf. facsimile given by Adelmann The Embryological Treatises of Hieronymus Fabricius of Aquapendente Adelmann H.B. New York 1942 432 432 ‘… Merito vermes qui propter eorum imperfectam naturam sexu non distinguuntur, uti elicitur ex Arist. iam mutari in aliam speciem debent, quae utrunq’ sortiatur sexum. Quòd ut fiat, primùm vermiculi ex ovis oriuntur; qui subinde aucti, erucae formam induút; ubi autem iustam magnitudinom receperunt, in folliculo includuntur, ibi aureliae, evadunt; ultimo papiliones…. Papiliones … tune sexu distinguuntur, & coëunt, tum demum ova pariunt, ut rursus eiisdem generis vermes flant, & generationis successio consequatur, speciesq' conservetur.’ Cf. Harvey's citation, Ex. 57/445, from p. 46 of Fabrizio (Adelmann, p. 428).
  • The comparisons are given in Ex. 62 476 481 see citation, foot-note 36, below.
  • Describing his findings during the fifth day of incubation of the chick egg, he notes: ‘There appears the figure of a vermiculus or worm—like the primordia for the worms and the caterpillars on branches of trees, in bark-blisters, in fruit, in blossoms, and elsewhere …’ Ex. 18 364 364 Cf. Ex. 62/478.
  • ‘Similiter se habet generatio … quorumlibet animalium; sive semen eorum casu adsit, sive ab agente univoco eiusdem generis proveniat. Quippe etiam in semine fortuito inest principium generationis motivum, quod ex se et per seipsum procreet; idemque quod in animalium congenerum semine reperitur, potens scilicet animal efformare’ Ex. 57 446 446
  • ‘… In generatione animalium, quaedam ex materia prius cocta et aucta formantur et transfigurantur; omnesque partes simul per metamorphosin oriuntur ac distinguuntur, perfectumque animal enascitur: quaedam vero, … per epigenesin…. Priori modo fit insectorum generatio, ubi vermis per metamorphosin [cf. foot-note 45, below] ex ovo [a “first egg”; cf. foot-note 36, below] nascitur; vel ex materia putrescente (humido siccescente, vel sicco humescente) primordia [hatched larvae] procreantur, e quibus (tanquam ex eruca ad perfectam magnitudinem aucta, vel ex aurelia) per [the second] metamorphosin papilio vel musca oritur iusta magnitudine, nec a primo ortu quidquam auctior fit…. In illis, casus seu fortuna videtur maxime generationem promovere; in quibus forma oritur ex potentia materiae prae-exsistentis, causaque prima generationis est materia potius, quam efficiens externum.’ In the next paragraph he goes on with the passage cited: ‘Quaedam igitur animalia sua sponte nascuntur, ex materia sponte vel casu concocta; ut Aristoteles Met. VII [c 9; 1034b5] videtur asserere. Quorum scilicet materia potest a se ipsa moveri, eo motu'a casu, quo semen movet in generatione aliorum animalium’, Ex. 45/350. See Ex. 50/386, cited, foot-note 43. Although Harvey quotes Aristotle to support the ‘chance’ influencing of the larva-pupa as parallel to influence via seminal fluid in univocal generation, they disagree in one respect: In univocal generation via insemination, what is contacted and directly influenced is a maternal ‘geniture’, according to Aristotle. The ‘geniture’ is up-graded to fecundity. For Harvey, in univocal generation, the female organism is contacted and directly influenced and advanced to such fecundity as to produce a (fertile) conceptus. They agree in at least this: The larva-material is not activated by seminal fluid, as an ‘efficiens externum’; but, with concurring ‘chance’ influences, the larva can proceed spontaneously.
  • By ‘geniture’ Harvey and Aristotle mean parent-produced material entering into fertilization. Seminal fluid is the male geniture. It is a homogeneous material; at insemination it is in an activated condition which lasts only for a limited time. There is no suggestion of microgametes. Maternal genitures would be, e.g., an unfertilized fish-egg, or, according to Aristotle, the mammalian catamenia at the uterus before insemination has affected this refined material. See, e.g. Ex. 14 241 241 Ex. 26/292; Ex. 32/309; Ex. 40/331; Ex. 50/333; Ex. 63/483; Ex. 72/537.
  • Ex. , 62 480 – 480 . Two pages before, Harvey classifies ova thus: ‘We designate as complete [perfecta], those finished in the uterus; they attain full size before being deposited. Such are the eggs of birds. We call incomplete [imperfecta] those extruded earlier, which have not yet achieved full size but are enlarged post partum—as those of the fish, crustaceans, and molluscs. Similarly: the primordia of insects called scolices by Aristotle are referred to this group, also the primordia of those which arise spontaneously…. From some incomplete eggs, properly called ova—as those of fish—a completed animal is procreated. [Harvey took the fertilized fish-egg to be uncompleted until it had swelled; after that it formed the embryo.] There are others, improperly called ova, from which arises an incomplete animal, namely a scolex or a caterpillar. This worm [larva] is midway between a completed and an incomplete ovum’, Ex. 62/478, 479. Thus, insect ‘first eggs’ are improperly called eggs and are incomplete.
  • Ex. , 57 445 – 445 . On the next page, he states: ‘Eodem modo generantur tam ea, quae sponte oriri dicuntur, et materiam suam primam primave exordia [first eggs] a putredine, coeno, rore, excrementis, vel partibus stirpium aut animalium, casu fortuitove nanciscuntur; quam illa, quae ex semine animalium congenerum proveniunt. Quippe omnibus viventibus id commune est, ut ex semine ceu ovo originem ducant; sive semen illud ex aliis eiusdem speciei procedat, sive casu aliunde adveniat.’
  • See Willis The Works of William Harvey, M.D. New York 1847 lxxi lxxi foot-note 26 above. One way Harvey has of saying that the egg is an individual organism, not part of the host, is by saying that the source of operations is the organism's own anima.
  • Ex. , 18 264 – 264 . He refers to plant parasites at several points, v.g., to ‘the vermiculi coming from plants and their fruits … in galls, cocco baphico, rose ovaries, and many others. “An animal can be created in almost anything—whether as the moist dries or as the dry moistens. [Arist. Hist. An. V. 32]”.’ Ex. 27/297. Cf. foot-note 33, above, and foot-note 45, below.
  • Harvey usually has reference to insect generation via internal fertilization. But the notion of a-sexual or of parthenogenic reproduction was of course as old as Aristotle; see Ex. 50 386 386 And there is the statement: ‘… many insects (including silk-worms, and butterflies), conceive eggs and oviposit without insemination (as also do fish); but the eggs are unfertile and subventitious’. Ex. 5/201. Parthenogenesis (of fertile eggs) and production of non-fertile eggs would also be ‘spontaneous’.
  • Origination ex putredine is a common designation of Harvey's for a-biogenesis (the modern term) from various substrates. Whatever his terminology, and whether or not he thinks a-biogenesis ever occurs, Harvey clearly refers to it at least at the following points Ex. 29 304 304 (plants, not from seed); Ex. 38/323; Ex. 41/337; Ex. 45/350; Ex. 50/386; Ex. 57/446; Ex. 62/476; Ex. ‘On Parturition’/548; Ex. ‘On Uterine Membranes’/573. Loci seemingly referring to a-biogenesis, but not so expressly, are: Ex. 1/182; Ex. 18/264, 265; Ex. 27/297.
  • He cites Aristotle's reference to cicada eggs from ‘foeminae a coitu suaviores’ Ex. 62 478 478 The same chapter (5) of the ancient Historia Animalium, as well as chapters 7, 8, 17, 19–32, often deal with production of eggs ‘ex coitu’. Harvey contrasts infertile silk-worm and butterfly eggs with those produced after insemination, Ex. 5/201.
  • Speaking of ‘cuncta animalia’, he writes: ‘Quorum quaedam sponte nascuntur sine aliquo efficiente univoco; quaedam maris foeminaeque simul sociatis operis; quaedam ab alterutro duntaxat sexu; quaedam per alia instrumenta intermedia, eaque interdum plura, interdum pauciora; quaedam instrumentis univocis; quaedam aequivocis et ex accidente generantur’ Ex. 50 386 386 He goes on to say that ‘omnia corpora naturalia’ are instruments: ‘suntque haec vel naturalia solum, ut calor, spiritus, aëris putredinisve tepor et caetera, vel simul etiam animata …’. He parallels the male with various other ‘instruments’, which, as it were, are intermediate in effecting the adequate fecundity of the completed ovum: ‘Ex dictis itaque aliquatenus constat, quodnam a mare in generatione afferatur symbolum. Nempe gallus idem ovo confert, ut ex subventaneo prolificum evadat, quod vegetabilium fructibus tribuitur ab aestivo solis fervore, ut maturitatem consequantur et semina eorum foecunda fiant; idemque, quod sponte nascentibus foecunditatem affert; et ex vermibus erucas, ex his aurelias, ex aureliis papiliones, muscas, apes et caetera progenerat’ (Ibid.).
  • Ex. , 38 323 – 323 . That he refers inclusively to cases where the ‘spontaneous’ generation occurring ‘fortuituously’ is a-biogenetic, becomes clearer as he says further on that ‘the sun … or whatever is regarded as the common father in animal generation, procreates certain ones itself, through chance, as though without any instrument, equivocally’, loc. cit., 324. As to ‘only males’—the text reads: ‘In some [species], however, [one comes upon (supplying reperiantur from the preceding clause)] only the males, and no females are seen—because they all procreate by emitting something outside themselves into mud, soil, or the water’, loc. cit., 323. If there is ambiguity here, Harvey has made his mind clear that females are necessary in Ex. 29; cf. foot-note 48.
  • Ex. , 45 350 – 350 . see quotation, foot-note 33, above. He is possibly referring to the (first) egg rather than to the larva itself, as beginning a-biogenetically. He goes on to note the second metamorphosis, which he is accenting. (Harvey, like Aristotle, was aware of direct development in the cicada, locust, etc., cf. Ex. 57/446; Ex. 62/478. These have only one metamorphosis.)
  • Ex. , 62 476 – 476 . Aristotle, as Harvey quotes him: ‘… some arise spontaneously, without any preceding seed of [their] kind [Hist. An. V. 1]’. Cf. Harvey's generalization in the first citation of this paper.
  • Ex. , 18 264 – 264 . 265. Aristotle refers to the origin ‘from dew’ of (first) eggs ‘smaller than millet after which are tiny worms; then they enlarge for three days … (Hist. An. V. 19]’, loc. cit..
  • Ex. , 29 304 – 304 . He apparently refers to plants, here. He has quoted Aristotle's ‘Everyone regards the earth as feminine, and the mother; the heavens and the sun, however, and the rest of the same sort, are called by the title … father [De Gen. An. I.2]’. Then Harvey makes the remark quoted, adding: ‘… Some females procreate alone, without a male (as when the hen produces a wind egg); but males never generate anything without the female’.
  • Ex. , 57 446 – 446 . cited above, foot-note 37
  • It was pointed out that what Harvey calls the ‘spontaneously originated’ are not necessarily of a-biogenetic origin. The neutralizing contexts of each of the citations just made has been indicated. In addition: The opinion that some a-biogenesis was a fact had been in peaceful possession of the field—both ‘vulgar’ and scientific—since Aristotle; there was no burning question in the minds of Harvey's readers. In these circumstances he might well omit contesting the belief each time he mentioned it. A-biogenesis would not exclude ‘instrumentality’ Ex. 50 386 386 Ex. 38/322, 324; nor ‘Ex ovo omnia’ or metamorphosis—Ex. 45/350, Ex. 62/476, Ex. 18/264, 265, Ex. 57/445. Also, multiple references to a-biogenesis do not show that it is a possibility, in Harvey's mind. A (rather trying) feature of De Generatione is this: although at one point he clearly expresses his stand on an issue, Harvey keeps on repeating the speculated contrary solutions—e.g., re Fabrizio's ‘bursa’ in the cloaca of the fowl, Ex. 6/202, 203; Ex. 12/227; Ex. 26/292; Ex. 40/330; Ex. 48/369; or, re contact between ‘genitures’, Ex. 14/240–242; Ex. 26/292; Ex. 32/309; Ex. 34/315; Ex. 40/331; Ex. 49/372; Ex. 50/383; Ex. 68/501; Ex. 72/537; Ex. ‘On Conception’/593.
  • Harvey may be offering little more than the speculation of Fracastoro, De Contagione (1546), who theorized about infection by airborne seminaria contagionum—not necessarily living, according to Garrison An Introduction to the History of Medicine 1929 233 233 Harvey's Ex. 41 was written more than fifteen years (see foot-note 55, below) before microscopic data on infection: Garrison says, p. 253, that ‘the earliest of the microscopists’, Kircher, Scrutinium Pestis (1658) ‘was undoubtedly the first to state in explicit terms the doctrine of contagium animatum as the cause of infectious disease’. (‘Living’ [animatum] was an ambiguous term—cf. Ex. 27/298—even after the observation of micro-organisms; cf. Garrison, p. 233, foot-note 1. Unambiguously, at many points in his book, Harvey regards the ‘seeds’ for larvae as individual, living organisms.) Harvey deals mainly with the transfer of a ‘hidden’ contagion factor in air, buildings, clothing, with its latent period, with its virulent potential for widespread havoc to ‘man and beast’ (Ex. 41/338)—speculatively comparing it with rot, odours, etc. He does not say that it is living [animatum] (but cf. Ex. 27/298), or that it is corpuscular. Cf. G. Sarton, Six Wings, London, 1958 pp. 206, 207, 211.
  • The features of ‘contagion’ which Harvey compares with those of seminal fluid as it contacts the maternal organism and later effects ‘fecundity’, etc., are these: momentary contact by contagion material (perhaps non-living); an a-symptomatic interval; then, production of disease like that of the earlier patient; the power of the contagion in pervading the whole organism of the patient. Concerning Harvey's discussions of ‘fecundity’, cf. Foote An Organism's “Soul” as Described by William Harvey, M.D. Rome 1964 18 ff 18 ff pp. 77–83
  • Harvey compares some features of contagion with those of the ‘eggs’ for larvae, others with those of seminal fluid. Points of similarity between the contagion factor and the subvisible eggs include the transfer from a distance, ‘through the air’. The comparison of ‘contagion’ with seminal fluid has nothing to do with such transport, or with ‘wind eggs’. Bayon William Harvey … Ann. Sci. 1939 377 377 seems to confuse the issue. The larva ‘seeds’ are corpuscular and living; Harvey describes seminal fluid as homogeneous (cf. foot-note 35, above) and considers that it and contagion both may be not living (Ex. 52/397, 398; Ex. 49/373). Bayon, op. cit., p. 59, departs from Harvey, I think, in suggesting ‘sperma’ in the fluid; but cf. his remarks, p. 57.
  • See Ex. 57 445 445 for the text
  • Harvey seems to have composed the Exercitationes in sequence as numbered. As late as Ex. 62 480 480 he anticipates reporting on insects. Hence he wrote Ex. 41 well before the Rebellion—which, as he notes in Ex. 68/502, changed his plans. (Cf. foot-note 5, above.) The contagion idea persisted until after the publication of De Generatione, as Harvey's notes on the fly-leaves of a copy show—cf. Needham, op. cit., p. 123; here ‘insect seeds’ are again mentioned. (Contagion is discussed in Harvey's 1653 letter Opera (1766), p. 627, to Nardi—but only with reference to fertilization.)
  • Harvey refers to tenets in which a-biogenesis replaces the parent's producing a (first egg—in Ex. 41 337 337 Ex. 57/446 (cited, foot-note 37, above), Ex. ‘On Parturition’/544; it replaces the (first) egg's producing the larva—in Ex. 45/349, 350. Which of the primordia—egg, larva, or pupa—would begin a-biogenetically, is indefinite in Ex. 38/323, Ex. 50/386, Ex. 62/476, and in Ex. ‘On Uterine Membranes’/573. The primordium referred to in Ex. 18/264, 265 and Ex. 27/297 is the (first) egg, that in Ex. 1/182 is indefinite; but perhaps a-biogenesis is not referred to in these three loci.
  • See foot-note 50, above. Although De Generatione does not establish that Harvey believed a-biogenesis ever occurs, he writes, in the beginning of Ch. 17 of De Motu Cordis Frankfurt 1628 64 64 as if he did accept the ex putredine origin of some larvae (and some worms).
  • Some analysis of Harvey's basic life-science is incorporated in a study, ‘Harvey: Materials and Causes in Generation’, not yet published. Cf. Foote An Organism's “Soul” as Described by William Harvey, M.D. Rome 1964 22 26 33–36
  • According to Bayon William Harvey … Ann. Sci. 1939 61 61 65

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Order Reprints Request Corporate Permissions

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

Request Academic Permissions

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.

Related research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.