BAcTzmwom cAL REvIEWs, June 1976, p. 270-275Copyright © 1976 American Society for Microbiology

Vol. 40, No. 2Printed in U.S.A.

Lazzaro Spallanzani's Opuscoli of 1776RAYMOND N. DOETSCH

Department of Microbiology, University of Maryland, College Park, Maryland 20742

INTRODUCTION...................................................... 270THEORIES OF BUFFON AND NEEDHAM ....................... ............ 270SPALLANZANI'S POSITION: PREFORMATIONISM ........... ............... 273EXPERIMENTS WITH INFUSIONS .......................................... 274LITERATURE CITED ............... ........................... 275

INTRODUCTIONLazzaro Spallanzani's (1729-1799; Fig. 1) dis-

putations with John Turberville Needham(1713-1781) and Georges Louis Leclerc, Comtede Buffon (1707-1788), reached their apogee in1776 with the publication, at Modena, ofPhysi-cal Observations on Animals and Plants(Opuscoli de Fisica, Animale e Vegetabile)(Fig. 2). The book is subtitled Observations andExperiments on Infusion Animalcula Occa-sioned by an Examination of Some Articlesfrom a New Work by Mr. Needham (Osserva-zioni e Sperienze intorno agli Animalucci delleInfusioni in occasioni che si esaminano alcuniArticoli della nuova Opera del Sig. de Need-ham). Included in this span of 304 pages (iden-tified as "Tomo Primo") are two letters, onequite long, one brief, written to Spallanzani inJanuary and April of 1771, by Charles Bonnet(1720-1793), a well-known preformationist,"relative to ideas on infusion animalcula" (rela-tive al Suggetto degli Animali infusori).Opuscoli was not Spallanzani's first work

dealing with the extremely controversial andconfused (at the time) issue ofgeneration mech-anisms. In 1765 his Microscopical Observationsin Regard to the Generation Theory of Need-ham and Buffon (Saggio di Osservazioni Mi-croscopiche Concernenti il Sistema delta Ge-nerazioni dei Signori di Needham e Buffon)appeared, followed 4 years later by Abbe Re-gley's translation of the work, New Investiga-tions, Microscopical Discoveries, and the Gen-eration of Organized Bodies (Nouvelles Re-cherches sur les DIcouvertes Microscopiques, etla Generation des Corps Organises) (Fig. 3).This translation was furnished with copious"notes" supplied by Needham, and the originalwork occupies only 138 pages, while the notes,which are, in fact, a detailed rebuttal of Spal-lanzani's experiments, occupy 159 pages.

THEORIES OF BUFFON AND NEEDHAM

To obtain a clear idea of the nature and im-portance of Opuscoli, it is necessary to sketch

briefly the background and scientific positionsoccupied by Buffon (as he was generallyknown) and Needham with respect to theirviews on generation. This matter has been ex-cellently recounted by Gasking (2). The formerhad developed his ideas on the subject for someyears before they appeared in 1749 in the sec-tion of his monumental Histoire Naturelle ti-tled Des Animaux (volume II). While visitingin England in 1738, Buffon met and discussedhis theory with Abbe Needham, and this en-counter established the basis for their later col-laborations. As for Needham, his views wereexpressed at great length in December 1748, ina paper titled "A Summary ofSome Late Obser-vations Upon the Generation, Composition,and Decomposition of Animal and VegetableSubstances; Communicated in a Letter to Mar-tin Folkes Esq., President of the Royal Soci-ety, by Mr. Turbervill [sic] Needham, Fellow ofthe same Society" (Philos. Trans. 45:615-666).

Buffon obviously was influenced in the con-struction of his theory by P. Gassendi's (1592-1655) De Vita et Moribus Epicuri (1647), a re-vival of Epicurus' theory leading to develop-ment of the later micromechanical outlook inbiology, particularly in the realm of all vitalphenomena, not only sexual reproduction. Buf-fon's ideas on nutrition and generation are notalways easy to translate into meaningful termsof modern biology, but he proposed, in essence,that every living being was built from a largenumber of organized bodies consisting of or-ganic molecules, microscopically or sub-micro-scopically small. In a plant or vegetable, thewhole body served as a template or mold(moule) into which absorbed food was fitted. Inan animal or man, the entire mold was anassemblage of smaller molds, one for each partof the body. Ingested food was postulated tocontain both living and brute matter (matierevive et brute), and the body separated the two,rejecting the latter by the excretory mecha-nisms of kidneys and alimentary tract. All ofthe molds, each in its own part of the body, tookfrom living matter of food, now in the blood,

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SPALLANZANrS OPUSCOLI 271

FIG. 1. Lazzaro Spallanzani by Giovanni Battista Busani (courtesy ofthe National Library ofMedicine) .

those organic molecules best suited to them,and hence they expanded, or grew, in all direc-tions. When an organisms was fully grown, itsmolds no longer required all of the organic mol-ecules available to them, and the excess went,

via the blood, to those parts of the body in-volved with reproduction. Buffon believed thatfor reproduction, the excess food formed a tinyorganized body whose mold was similar to, or acopy of, the mold of the entire body. On the

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pound Bodies in Nature, not rising above theCondition of Machines, which yet might seemto be alive, and spontaneous in the Motions,such as the Calamary Machines would cer-tainly appear, if they were rendered so diminu-tive as to conceal their Mechanism, and such Ithen suspected the spermatic Animals to be: forMotion in general was but an equivocal Argu-ment, and did not necessarily imply Life in thecommon Acceptation of that Term" (paragraph19, page 634; apparently a printer's oversightled to the omission of pagination numbers forNeedham's article, but the next to last paper inthis issue of Philosophical Transactions endsat page 614, so the reader has to "fill in" theblanks from there to the end of Needham'spaper, which concludes volume 45). Needhamwas quite clear in the objective of his research,namely: "... our Enquiry commence(d) uponSeed-Infusions, from a Desire Mr. de Buffonhad to find out the organical Parts, and I, ifpossible, to discover which among these Bodies

FIG. 2. Title page of the 1776 edition of Spallan-zani's Opuscoli.

other hand, reproduction in simple plants wasachieved frtom the smallest possible part, be-cause the multimolecular organized bodies thatcomprised plants were considered both likeeach other and the whole organism. Thus, theentire plant was an assembly ofidentical bodieseach able to form a new whole. Buffon consid-ered the organic parts to be "primitive andincorruptible." Dead organic matter could stillcontain vital organic particles, but since thespecific moule had been destroyed, its orga-nized particles could "separate out." Buffonthought that the moving objects seen in variousorganic infusions might, in fact, be these sepa-rated particles. It is particularly important tonote here that the animalcules observed in var-ious infusions were believed to be authenticliving organisms carried into them aerially. Itwould be Needham's main task to determinewhether this was true. It was at this criticalpoint, then, that Spallanzani's main experi-mental endeavors would be directed.At first Needham wrote: "For my part, I was

then, as I had been before, so far of his [Buf-fon's] Opinion, as to think there were Com-

Par NO";dm, Menmbre de 1* Sodild RoeC dAmScienctsX & de cslle des Antiquaires dc Lndres, KCCorrCfpntdta dAe I'Avadnue des Sciences de Pais.

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Chez L AC0c Ma a, Libraire, rue Chrifline, pM'sla rue Dauphine.

M. D C C. L X t A

FIG. 3. Title page of Needham's French transla-tion ofSpallanzani's Saggio.

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SPALLANZANrS OPUSCOLI 273

were strictly to be look'd upon as Animals, andwhich to be accounted mere Machines" (para-graph 19, page 634.).Needham was primarily an experimentalist,

and his talents far exceeded Buffon's in thisregard, but as his inductions from hazardousobservational work lead him on he finally con-cludes: "It was not till some time after this,that, determin'd to convince myself and others,without any Possibility ofDoubt, whether thesemoving Atoms were really produced from with-out, or from the very Substance infus'd: I dis-covered all the common microscopical Animal-cules, the spermatic ones not excepted, were tobe rangd in the same Class, and that theirGeneration was very different from that of allother animated Beings" (paragraph 20, page637.) This conclusion, quite at variance withBuffon's hopes, was derived from results ini-tially based on the microscopical examination

of roast meat gravy ".. hot from the Fire, andshut ... up in a Phial, clos'd with a Cork so wellmasticated, that my Precautions amounted toas much as I had sealed my Phial hermeti-cally," and also ". . . upon three or four Scores ofdifferent Infusions of animal and vegetableSubstances ... all which constantly gave methe same Phaenomenon with little Variation,and were uniform in their general Result" (par-agraph 31, pages 637, 639.) Thus it was thatNeedham found it necessary to shift his posi-tion radically and he wrote, ". . . we began tolay down a Distinction between animated andmere organizd Bodies; which tho' far frombeing at this time groundless, yet afterwardsproved false. These, and the spermatic Ani-mals, we supposed to be of the latter kind; andto be produced in their respective Fluids, by aCoalition of Active principles ... whilst wethought on the contrary, that the ordinary mi-croscopic Animalcules, with strong Character-istics of spontaneous Motion and Animation,

were to be class'd among Animals, and im-agin'd them to proceed from Parent individualsof their own Species" (paragraph 20, pages 636-637).Needham now had abandoned his precon-

ceived distinction between the animalcules ofinfusions and the so-called atomical ones, andadopted the view that"... vegetative Powers... reside in all Substances animal or vegeta-ble, and in every part of these Substances, asfar as the smallest microscopical point" (para-graph 25, page 644.) One does not find Need-ham suggesting that organic molecules formpatterns that are replicas of the whole orga-nism, and he emphasized his discovery of theexistence of a "vegetative Force." He observes

". . . hence it is probable that every animal orvegetable substance advances as fast as it canin its Resolution to return by a slow Descent toone common Principle, the Source of all, a kindof universal Semen; whence its Atoms may re-turn again, and ascend to a new Life" (para-graph 29, page 654.) Buffon was still explainingthe origin of spermatic animals by ". .. an evo-lution and combination of organical parts."Thus, in Needham's view, some animalcula ofinfusions derive only from "seeds" producingbeings like themselves, and these are presentin the air and, therefore, in newly preparedunheated infusions, whereas those seen in ves-sels containing heated, sealed infusions, areresultants of the action of a vegetative forceacting on the organical molecules constitutingthe infusion. In either case, all infiisoria wereconsidered to belong to the same class. It appar-ently never occurred to Needham to test thevalidity and soundness of his experimental con-ditions since he was quite blinded by the en-ormity of his great "discovery."

SPALLANZANI'S POSITION:PREFORMATIONISM

Spallanzani was a preformationist and fur-thermore, an "ovist." He firmly believed thatall parts of a new individual were preformedwithin the ovum. Since it was difficult to ex-plain how differentiated parts could arise fromunorganized materials, 17th century preforma-tionists had assumed that all living things wereorganized by God at the moment of creation.The first female of each species had presentwithin herself all future generations of herkind. Each generation gave rise to the nextuntil all of the initially created ova had reachedtheir maturity-then the species became ex-tinct. This view was known as emboitement,and it was preformation plus emboitement thatwas the essence of the theory in the 18th cen-tury.

Spallanzani, along with A. Haller (1708-1777) and C. Bonnet, were the three great pre-formationists of this century. During the years1730-1760, preformation theory became lessreadily accepted, although the ovist versiongave it new life for a considerable time, largelydue to the efforts of these three men. Inciden-tally, none of them began as a preformationist,but became convinced of the correctness of thistheory later in their careers.The work contra Needham and Buffon repre-

sented only a small facet of Spallanzani's inves-tigations on generation, but it is the part rele-vant to microbiology. In passing, it may benoted that for all of Spallanzani's experimental

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flair, and despite the fact that his results gener-ally have remained firm, the work did little toclarify the basic biological issues of the time,and indeed, his results were misinterpreted bythe need for forcibly fitting them into currentpreformationist dogma.

EXPERIMENTS WITH INFUSIONSAs a preformationist, Spallanzani could not

persuade himself to the view that the animal-cula of infusions were brought to life by a conca-tenation of vegetative force with organic mole-cules. C. Bonnet already had written of a "pre-existence of infusoria." Thus Spallanzani setabout to determine other reasons for their pres-ence in Needham's infusions. The prior experi-ments of his countryman, F. Redi (1621-1697),and the Frenchman, L. Joblot (1645-1723),clearly provided models for Spallanzani. InRedi's case, insects were shown not to arisespontaneously from decaying meat by the sim-ple expedient of covering vessels containing itwith a thin cloth, thus excluding their egg lay-ing parents (Esperienze Intorno alla Genera-zioni degl'Insetti, 1668). And Joblot's experi-ments, even more to the point, that hay infu-sions boiled for 15 min and then covered withparchment did not give rise to any "living in-sects" or infusoria (Descriptions et Usages deplusiers Nouveaux Microscopes, 1718). It wasbecause ofSpallanzani's expertise as an innova-tive experimenter that the results documentedin the Opuscoli turned out the way they did. AsSpallanzani wrote in the concluding chapter(12) of part II (page 203): "The infusion animal-cula are simply not'vital beings' in Needham'ssense, but exhibit true and characteristic prop-erties of animality" (Gli Animali infusori nonsono Esseri semplicemente vitali conforme ilpensare del Needham, ma hanno le vere, ecaratteristiche note dell'Animalita). Movementwas considered to be solely an "animal prop-erty" long after Spallanzani's time.

Most, but not all, experiments described inthe Opuscoli consist of microscope observationsmade on infusions of kidney beans, vetches,buckwheat, barley, maize, mallows, beets, etc.,heated in closed vessels for various periods oftime, set aside to await developments thatwould be observed macro- or microscopically.The presence and viability of the animalculawas judged mainly on their ability to move orexhibit translational motility. Animalcular re-production was noted macroscopically by an in-crease in turbidity of the infusion under study.The effects of vacuum, "electrical fluid," heat,cold, and various scents and liquids on the proc-esses of motility and reproduction in animal-

cula constituted a major part of Spallanzani'sinvestigations. As far as microscope techniquewas concerned, a statement in the Saggio of1765 tells the reader that"... in my observa-tions on infusion animalcula, I generally usedan instrument similar to those of Leeuwen-hoek's; it consisted of a single lens strongenough to easily observe them with precision,including the most delicate and fine details"[author's translation]. Spallanzani also used acompound microscope, but this notwithstand-ing, it is difficult, if not impossible, to identifytoday many of the organisms (mainly protozoa)he described in his work. The simple micro-scope was used in both a horizontal and verticalposition, and candle light reflected from a con-cave mirror served as the illumination source.Spallanzani wrote that Needham used essen-tially the same microscope technique.Nineteen flasks containing vegetable infu-

sions were hermetically sealed and kept for 1 hin boiling water. Upon examination, after aperiod of incubation at room temperature, not asingle animalculum could be detected. None-theless, if these infusions (of white kidneybeans, vetches, buckwheat, barley, maize, andseeds of mallows and beets) were now freelyexposed to the air, all showed the presence ofinfusoria in a day or two. Spallanzani con-cluded that long heating per se had no effect onthe vegative power of these infusions. Indeed,11 kinds ofseeds were reduced to ash by holdingover burning coal, and infusions prepared fromthese ashed seeds also showed the presence ofanimalcula in a few days.One learns from the Opuscoli that all ani-

malcula die at a temperature "around boiling,"but that ".. . all animalcula are not alike af-fected by cold." It is also noted that". . . everyfluid is not equally favourable for the expansionof animalcular eggs. Pure water alone is unfitfor it; hence it is no longer a mystery, why in it,and much more in distilled water, we hardlyever see animalcula" (1).

In another section, Spallanzani observed that".... vapors of camphor ... occasioned suddenagitation and discomposure in the animalcula:they endeavoured to retreat from the malig-nant fumes, by retiring deep into the infusions"(1). Here, one might easily imagine, is an ob-servation on negative chemotaxis-perhaps thefirst ever recorded. Spallanzani also deter-mined that salt water, vinegar, ink, brandy,and spirit ofwine were fatal to animalcula. Oneneed not cite further examples of these simpleobservational experiments to ask, as Bonnetdid, in his letter of 17 January 1771, referring tosome of Spallanzani's experimental results, 4

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years before their publication in the Opuscoli:"How can we refuse to assent to the generalconclusions which you deduce from such deci-sive experiments? How can we refuse to agree,that the vegetative or productive power of ourfriend the Epigenicist is a perfect chimera?" (1).

Most microbiologists appreciate the impor-tance of Spallanzani's work on infusion animal-cula. His conclusions were sharply outlined, aswe may gather from his statement: "As I couldnot then conceal my propensity to believe, thatinfusion animalcula originated from germs,

neither do I hesitate to say, propensity hasbecome perfect conviction. If the animalcula donot originate from the vegetative power, I donot see how we can ascribe their origin to anything but eggs, seeds, or preorganized corpus-

cles, which we understand and distinguish bythe name of germs" (1).

But, of course, the matter did not end withthe appearance of Opuscoli, and as is wellknown, the Needham-Spallanzani controversyslowly faded away in a mist of equivocation. Ithas been pointed out on more than one occasionthat spontaneous generation cannot be "dis-proved." One can only show that it does notoccur under the experimental conditions advo-cated by proponents, or that erroneous conclu-sions were drawn from correct observations.Spallanzani's bWte noire was his inability todevise an experiment that did not involve heat-ing (or "torturing" as his adversary said) the airover infusions. This innovation came later inthe work of F. Schulze (1815-1873) and H. G. F.Schr6der (1810-1885) and T. von Dusch (1824-1890) (4, 5). Hence, an unequivocal conclusion,based upon incontrovertible experimental evi-

SPALLANZANrS OPUSCOLI 275

dence, that the air did not contain some heat-labile element essential for operation of a "veg-etative power" was not possible in Spallanzani'stime. The Opuscoli clearly foreshadowed thepattern of experiments in this direction, and inthis respect Spallanzani's influence on futuredevelopments was more than passing, culmi-nating in Pasteur's epic work nearly a centurylater (3).Let us conclude, then, as the ASM observes

and honors the 200th anniversary of the publi-cation ofOpuscoli and the great Italian master,with words from Dalyell, who stated in histranslator's preface; "The acknowledged fameof the celebrated author of these tracts, and theimportance ofhis numerous discoveries, are toowell established to require any additional con-firmation here."

LITERATURE CITED1. Dalyell, J. G. 1803. Tracts on the natural history

of animals and vegetables. Translated fromthe original Italian of Abbe Spallanzani, 2nded, vol. 1. William Creech and Archibald Con-stable, Edinburgh.

2. Gasking, E. B. 1967. Investigations into genera-tion. Johns Hopkins Press, Baltimore.

3. Pasteur, L. 1862. Mdmoire sur les corpusclesorganisms qui existent dans l'atmosphere. Ex-amen de la doctrine des generations sponta-nees. Ann. Chem. Phys. 64:5-110.

4. Schroder, H. G. F., and T. von Dusch. 1854.Ueber Filtration der Luft in Beziehungen aufFaulniss und Gahrung. Ann. Chem. Pharm.89:232-243.

5. Schulze, F. 1836. Vorlaufige Mittheilung derResultate einer Experimentalen Beobachtunguber Generatio Aequivoca. Ann. Phys. Chem.39:487-489.

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