Generation and infusoria

In order to avoid spreading the subject, I will restrict the following inquiry to the issue of infusoria and related topics such as the quarrel of generation and the emergence of the systematic of microscopic beings.

With respect to the quarrel of generation, two main episodes have been widely analysed by historians: the Buffon-Needham-Haller-Bonnet quarrel between 1749 and 1764, and the renewal of the polemic opposing Spallanzani and Bonnet to Needham

(1765-1776).⁹⁵ Spallanzani is credited by historians of science to have demonstrated for the first time the vacuity of the spontaneous generation of organisms.⁹⁶ However rare studies have examined the reception of his theory abroad, except the relations with Charles Bonnet (1720-1793) and the continuation of the polemic with John Turberville Needham (1713-1782).⁹⁷ Some historians followed old Clifford Dobell’s and Emile Guyénot’s judgments on Needham’s work. The animalcules, infusoria and microbes

“gave occasion to fancy speculations and to the erroneous observations of a

Needham”.⁹⁸ But other historians have tended to justify Needham’s views by arguing that his criticisms towards Spallanzani’s experiments on the generation of the

animalcules were actually well-founded. Needham objected to Spallanzani that, when heating the sealed infusions, such a way of experimenting destroyed also the internal air, thus impeding any generation of the animalcules.⁹⁹ S. Roe and Mazzolini and Roe later have shown that philosophical conceptions also influenced the debate: Bonnet and Spallanzani’s opposed to Needham’s representations of life and its origins were rather incompatible, the former being influenced by a preformationist-mechanistic view, and

95 Roger 1993, 497-511, 692-717; Bernardi 1986, 409-415; M&R 1986, 30-52; Roe 1982, Farley 1977, 22-27; Castellani 1971.

96 Castellani 1973, 1991, 1992; Farley 1977, 25; Rostand 1943, 50-73; Bulloch 1938, 75-79;

Singer 1934, 460-461.

97 See M&R 1986, 30-52; Roe 1983, 1982, Farley 1977, 22-26; Grmek 1971.

98 Guyénot 1941, 442. See also Dobell 1932, 380. This judgment was however softened by Castellani 1969, 215-221.

99 Singer 1934, 461. Rostand (1943, 72-73) showed that Pasteur argued in a same way and justified Needham’s criticisms. See also Bernardi 2000, 54-56 and Roger 1993, 697.

the latter by an atomist-vitalist conception.¹⁰⁰ On the other hand, the role played by scholars from the Northern parts of Europe in this quarrel, and especially in relation to infusoria was thoroughly neglected. Historians hardly have mentioned and described the works of Heinrich August Wrisberg (1739-1808), of Otto-Friedrich Müller (1730-1784), and Wilhelm von Gleichen (1717-1783) who repeated Needham’s experiments, in defense of the spontaneous generation of inferior beings,¹⁰¹ to say nothing of the scores of scholars who had brought small empirical contributions to the issue. Important spread of their works could act as a relevant reason explaining why the spontaneous generation apparently acquired so wide an audience at the end of the century, since it was a theory also defended by important authors like Erasmus Darwin and Jean-Baptiste de Lamarck.¹⁰² Yet very seldom are the studies such as Ainsworth’s which in 1976 reconstructed an episode of the transmutationist debate between Linnaeus, Baron von Munchhausen, and the British naturalists, a dispute dealing with microscopical observations made on some spores of Fungi taken for animalcule’s eggs.¹⁰³

The study of the theories of generation, of embryology and of preformationism also supplied historians with other arguments against the scientific value of the microscope.

Elizabeth Gasking argued that the microscope indirectly strengthened the

preformationist’s views by embodying tiny structure invisible to the naked eye.¹⁰⁴ The microscope then encouraged fancy developmental interpretations such as those by preformationists who claimed that the body already existed as a whole in the germ.¹⁰⁵ Through the example of spermatology, Joseph Needham set many examples, from François de Plantade (1670-1741) to Gautier d’Agoty (1717-1785) of the imagined men and horses “observed” with the microscope and folded up in the spermatozoids.¹⁰⁶ Thus

100 M&R 1986, 10.

101 Stefani 1999, 329, Ruestow 1996, 261, 270-272; De Martin 1983, 81-84; Rostand 1943, 47.

102 Ruestow 1996, 275-276; Farley 1977, 38-45. Solinas (1969, 190) however has shown that Kant considered spontaneous generation to be impossible experimentally as well as conceptually.

103 Ainsworth 1976, 23-25.

104 Gasking 1967, 45-46.

105 For later development of the germ theory, see Fantini 1994, 111-115.

106 Needham 1959, 205-206.

the microscope is considered as having encouraged a kind of perverse effect on the theory. It strengthened, according to historians, the belief that invisible structures existed which reinforced some scholars in their views. Invisible structures were used to prove what the scholar wanted them to prove¹⁰⁷ --the truth of their own theories-- ignoring or neglecting the necessity of observations. Walter Bernardi pursued this line of reasoning further by charting a frontier between two visual regimes, of weak and of strong visibility. The former describes a way of observing in which the microscopical observations are influenced by theoretical assumptions. In such a regime an observation being at variance with the system would be discarded. Such was apparently done by Haller in spring 1765 when he tested anew the epigenetic hypothesis championed by Wolff accounting for the early development of the chicken’s blood vessels.¹⁰⁸ So that thanks to the microscope, the invisible was used as a strategy by preformationists. The strong visibility depicts the way to observe in the epigenetic system for which the observation prevails over the theory.¹⁰⁹ Nevertheless Roe also showed that the epigenesists used such a top-down --weak visibility-- approach when examining microorganisms : “In March 1748 Buffon and Needham started to test the hypothesis that both spermatic animalcule and all microorganisms were only machines emerging from a random combination of organic particles, a theory suggested by Buffon”.¹¹⁰ Both presented in 1748 and 1749 two interpretations accounting for the origin of animalcules: Buffon stood firm on the organic particle theory, and credited hazard with a leading role in the making of these small machines, including the “spermatic

animalcules”, and Needham built a theory of the transmutation from the vegetable to the animal. Partly through these examples historians have drawn the conclusion that microscopy, during the Enlightenment, was in a state of regression by comparison with previous studies by Leeuwenhoek who had indeed established the animal nature of both infusoria and spermatozoids. But the episodes of the 1740-1760 period radically

107 Roe 1981, 84; Bracegirdle 1978a, 12.

108 On this topic, see Monti 1990, 183-189, Roe 1981, 60-61; J. Needham 1959, 22.

109 Bernardi 1995, 33-34.

110 Roe 1983, 161.

changed the conditions of vision, and Jacques Roger has deeply thrown light on the question, considering that “by the 1750s, scientific observation ceased to be within amateur’s reach”.¹¹¹ .

If many studies have embraced the question of the origin of infusoria around Needham and Spallanzani, there are however almost no studies devoted to the history of the systematic of infusoria, and to their microscopic determination and description.

Historians probably recorded some eighteenth-century’s scientific discoveries regarding the structure and life of “animalcules” : the contractile vacuole of Protozoa recognised by Louis Joblot in 1718, the discovery of free-living amoeba in 1755 by Rösel, the identification of diatoms by Müller in 1773, and the property of reviviscence of the rotifer.¹¹² But actually one can not consider that the extant references and methodology hold the key bringing to a systematic inquiry on the history of infusoria. An example of such indistinctness of the research sharply stems from the question of the discovery of the division in infusoria (fission). Dobell considered Leeuwenhoek to have detected the reproduction of Volvox; John Baker has held Trembley, in 1744, to be the first discover of the division of unicellular beings; Rooseboom looked upon the British naturalist John Ellis as having made the discovery in 1769. Still for 1769, Mazzolini and Roe have put forward the names of Needham and that of H.-B. de Saussure (1740-1799), one of the Genevan intellectual heirs of Bonnet, while other historians have ascribed the discovery to Lazzaro Spallanzani in 1776!¹¹³ Obviously the subject calls for further inquiry.

As a consequence, except for Leeuwenhoek’s contribution about infusoria,¹¹⁴ we actually know more things regarding the history of words such as protista and infusoria

111 Roger 1993, 195. A study of the antispontaneist research of this period, through the categories of the forms of communication and the rationalisation of the practices of the microscope is available in manuscript.

112 Ruestow 1996, 261-262; Rothschild 1989, 279; Bracegirdle 1978, 12; Van der Paas 1973, 110;

Rooseboom 1956, 56; Cole 1926.

113 Lenhoff and Lenhoff 1986, 13; M&R 1986, 39-40; Castellani 1971, 8; Roseboom 1956, 48;

Baker 1952, 155-162; Dobell 1932, 380.

114 Ford 1991, 38-47; Bulloch 1938, 22-30; Dobell 1932.

than the history of infusoria strictly speaking. It was Gmelin that entered the Protista in the Linnaean classification with the name of infusoria in the 13th edition of the Systema Naturae.¹¹⁵ The word Protozoa seems not to belong to the Enlightenment, having likely been created in 1817 by Georg A. Goldfuss in Ueber der Entwicklungsstufen des

Thiers.¹¹⁶ Infusoria itself appeared “during the latter half of the eighteenth-century (...).

The “infusion animals” of Martin Ledermüller, or the (latinized) “infusoria” of Heinrich August Wrisberg, made their debuts in the early 1760s to describe microscopic

organisms that appeared in infusions”.¹¹⁷ However, almost all the classical knowledge about the systematic of infusoria in the eighteenth-century takes its source from works published in the first part of the nineteenth-century, such as Histoire naturelle des zoophytes infusoires by Dujardin (1841). He identified the main steps in the

progression: John Hill was, in 1752, the first to give Latin names to the animalcules, Linnaeus grouped them under the appellation of Chaos, and Otto-Friedrich Müller in 1773 and 1786 systematically classified 379 infusoria.¹¹⁸ Without being more investigated, this view was popularised by the first handbooks of history of natural sciences, by Cuvier, and Hoefel.¹¹⁹ Even the most popular Larousse dictionary of 1880 copied out Dujardin’s genealogy,¹²⁰ a topic to which some precision was brought by Cole in 1926 and Bulloch in 1938.¹²¹ Cole corrected for instance the date Dujardin attributed to Joblot’s first observations of animalcules (1718 instead of 1754). Bulloch also gave Joblot --himself a whole chapter in the history of infusoria-- a respectable place in the history of protozoological research.¹²² Yet historians seem unable to imagine suitable means to analyse the problem represented by the creation of the systematic of infusoria between 1773 and 1786, when not ignored: “It is well known

115 Guyénot 1941, 91.

116 Rothschild 1989, 279; Dobell 1932, 378.

117 Rothschild 1989, 278.

118 Dujardin 1841, 3-11.

119 Cuvier 1845 V, 271-272; Hoefel, 1873, 249-250. Carus (1880, 455) who praised Müller, ignored the attempt by Hill.

120 Larousse 1880, 690, entry “Infusoire”.

121 Bulloch 1938, 37, 171-172.

122 Bulloch 1938, 70-71. See also van der Pass 1973.

that Leeuwenhoek published figures of four forms of bacteria, and Otto Müller’s work on infusoria, published in 1786, did contain bacterial forms, but the systematic study was not taken up until the 19th-century”.¹²³Chapter 8 will reconstruct the system of sources showing the existence and importance of Müller’s works, as well as those by his predecessors. Indeed their comments on such a fundamental taking-off end up with arguments that mainly highlight the lack of this work in contrast with the studies of the following period, especially those of Christian Gottfried Ehrenberg (1795-1876).

Historians usually have stated that Müller, in his 1786 Animalcula infusoria

confounded worms, protozoa and metazoa,¹²⁴ that he made “errors difficult to account for” such as taking a diatom --a vegetable-- for an animal, and they have pointed at some holes in his descriptions, for instance Müller did not notice the cilia in P.

Aurelia.¹²⁵ Historians have sometimes identified the improvements of the classification from those by Hill and Linnaeus until that of Müller.¹²⁶ So that the same cliché, which after all is said and done seems a badge to be classified “historian of microscopy”, is once more used for infusoria: “Despite such implications --and the expectation, indeed, that so much was yet to be learned from the infusoria-- the eighteenth-century failed to develop the study of microscopic life into a sustained and integrated field of

research”.¹²⁷ And why did this programme not develop? Following Bulloch, Dobell, and Corliss, Ruestow has recently considered that “Müller’s achievement hence stands alone among eighteenth-century studies of microorganisms, and, since he lacked immediate heirs of significance, such efforts had come to a halt by the opening decades of the following century”.¹²⁸

I will here draw attention to a contrast between “studies” on Müller and the infusoria which almost did not round the cape of allusions, and studies on Leeuwenhoek. Both

123 Turner [1967], 175.

124 Ruestow 1996, 276-277; Rothschild 1989, 278-279; Corliss 1986, Guyénot 1941, 91; Singer 1934, 357; Dobell 1932, 376.

125 Guyénot 1941, 90. Rothschild 1989, 279.

126 Ruestow 1996, 276; Bulloch 1938, 36-37; Dobell 1932, 375-378.

127 Ruestow 1996, 276.

128 Ruestow 1996, 277. See Corliss 1986, 476; Bulloch 1938, 29; Dobell 1932, 375-382.

scholars lacked “immediate heirs of significance”, which means that, according to historiography, their works were not developed in substantial fields of investigation after their deaths. But there is a striking difference, perhaps a discrimination between studies on Leeuwenhoek and on Müller. The bicentenary of the publication of the posthumous Animalcula infusoria by Otto-Friedrich Müller gave rise to a... four pages paper in the Journal of protozoology, though Müller is the founder of the systematics of infusoria between 1773 and 1786.¹²⁹ In the symposia on the history of protozoology (issued in JHB 1989), no study was dedicated to Müller, though he was hailed there as the Danish Linnaeus.¹³⁰ Still historians take almost always directly their material from good old classics History of Protozoology by Francis Cole (1926), Dobell’s Little Animals (1932)¹³¹ and Bulloch’s History of Bacteriology (1938). Such a methodology is somewhat surprising, because of two aspects: on one hand there are practically no historical studies about Müller’s works, as compared to Leeuwenhoek; on the other hand, as we will see in chapter 9, the historical knowledge from the 1840s onwards took gradually into account only Leeuwenhoek and seventeenth-century microscopy. Indeed, when comparing data on Leeuwenhoek and Müller during the 1840s with the present state of our knowledge, one is lead to think that the historiography about Müller and Enlightenment’s microscopy is more than one century behind the history of

seventeenth-century microscopy.¹³² For 150 years, historians have studied

Leeuwenhoek and alia, and for 150 years eighteenth-century microscopy has been neglected. As a consequence, I dare say that one of the functions of the classic

historiography of microscopy has mainly been to explain the “absence” of microscopy.

But such an absence, in a high proportion, is the product of the lack of interest in eighteenth-century microscopy --not in the microscope-- stemming from the previous historiography... So that we are lead to the conclusion that a part of this

129 An. 1986.

130 Rothschild 1989, 278. In his retrospect of the history of protozoology, Churchill (1989, 188) jumped from Leeuwenhoek to Lamarck and then Ehrenberg.

131 Dobell 1932, 371-381.

132 Such knowledge is displayed for instance in Dujardin 1841, Ehrenberg 1835, and Harting 1839.

See chapter 9.

historiographical trend has especially functioned as an obstacle to someone undertaking research on the period. Perhaps also the importance of spontaneous generation has taken a heavy toll, for, oddly enough, such a big hole in historiography represented by the ghostly Enlightenment microscopy coincides with the major period in which spontaneous generation was mainly discussed by scholars. Eventually “microscopy”

itself could appear as a nineteenth-century invention, and bear the anachronistic load close to the “history of biology” or of “vitalism” using nineteenth-century words to designate fields that did not exist during the Enlightenment.¹³³ I shall negate, along with the cliché, the object itself of the standard history of microscopy, and my study shall thus reconstruct the European network of practices of scholars who used the microscope.

It is not easy to break down so rooted a prejudice, and contemporary historians are from two decades confronted with quite similar a situation to the one eighteenth-century scholars stumbled over. On one hand, there is a dogmatic set of beliefs acting as obstacles to undertaking research on eighteenth-century practices of the microscope, a mythology I will attempt to deconstruct on chapter 9. On the other hand once one goes looking for primary sources, they display in most cases a flagrant contradiction with the expectations. As a result, and with very few exceptions, the historian always finds himself in rather the same situation as Leeuwenhoek, when he opened the corked vessel containing a four days old infusion, full of animalcules: the theory is wrong! But

instead of changing method, Leeuwenhoek did not stir his belief, and preferred to continue adhering to the antispontaneist theory.¹³⁴ For the historian, such a tension between being consistent with the expectations of the technical history of the

microscope, and the contact with the sources has probably been the principal hindrance to look at Enlightenment’s use of the microscope in greater depth. Up to the 1990s indeed, there are seldom studies that have brought positive data embodying

133 See Jardine 2000, 261-262.

134 See Ruestow 1984, 235-237.

century microscopical research in its practices and context, looking at what the uses actually were of the microscope in the scientific life. Studies by Castellani about Spallanzani, especially the publication of his experimental notebooks on embryology and generation issued in 1978, are exceptions. Even rarer are the studies that have ventured to draw from their data conclusions other than the usual song of the absence of a microscopical programme, or at least, that have imagined other causes than the “bad microscopes”. Bracegirdle himself, when looking at the sources was astonished to find that during eighteenth-century, “some striking scientific results were achieved”,¹³⁵ but this could of course not be the rule since scholars “worked in isolation”.¹³⁶ How strong is the prejudice! From the old-fashioned idea of the microscope used as a toy, historians might find a way to prove that their belief was true, and have invented the story of the isolated scholar, just because they did not look at the system of sources which allow a reconstruction of an issue.¹³⁷ The historians who have emphasised the importance of Dutch microscopy during the eighteenth-century, still have concluded that microscopy was absent. Marian Fournier inquired about particular aspects of Dutch microscopy admitting that many microscopical studies took place in the eighteenth-century. Yet she appealed to statistics in order to show both the preeminence of Leeuwenhoek and the

“decline of microscopy”.¹³⁸ These are good examples of the actual tension between following the credo and archive work. Nevertheless, from a decade, the attitude of historians of microscopy seems to have progressively changed and they did not any more make reference to the technological “proofs” brought by old Zanobio, Bradbury and Bracegirdle. Perhaps it is the sign that the spirit in which these studies were carried out belongs to a remote period in the history of microscopy. Some studies have

emphasised the impact of the microscope on the cultural realm and philosophical conceptions in the seventeenth-century.¹³⁹ Other trends, such as the question of

135 Bracegirdle 1978, 12.

136 Bracegirdle 1978, 12.

137 Ruestow (1996, 156) has shown that Leeuwenhoek’s works were embedded into expansive social interaction, but mainly with common people.

138 Fournier 1989, 1991, 5, 16.

139 Mazzolini 1997, Wilson 1995, Parigi 1993, Solinas 1967.

ambiguous animals have captured the attention of historians and some of them consider that the Enlightenment “was the time of the great microscopical discoveries, when creatures were found that did not seem to be constructed by analogy with other creatures at all”.¹⁴⁰ Barsanti has regarded the studies of ambiguous organisms by microscopists since the 1740s to serve as the basis of the new biology in the early nineteenth-century.¹⁴¹

Nevertheless, there is no smoke without fire. If, during more than one century,

historians have seldom found evidences for microscopy in the eighteenth-century, there are likely some reasons for this, which touches on their object: they looked for a

discipline where there is but a system of low visible practices. I shall then challenge the current credo, arguing in favour of the following hypothesis. I do agree with the

historians who have shown that the fashionable and heuristic representation of the microscope of the second half of the seventeenth-century radically changed at the turn

historians who have shown that the fashionable and heuristic representation of the microscope of the second half of the seventeenth-century radically changed at the turn