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 o f generation and the emergence o f the systematic o f m icroscopic beings.
W ith respect to the quarrel of generation, two main episodes have been widely analysed by historians: the Buffon-Needham - H aller-B onnet quarrel between 1749 and 1764, and the renewal of the polemic opposing Spallanzani and B onnet to N eedham (1765-
1 7 76 ) . Spal lanzani is credited by historians of science to have
dem onstrated for the first time the vacuity of the spontaneous generation o f o r g a n i s m s . 9 4 How ever rare studies have exam ined
the reception of his theory abroad, except the relations with Charles B onnet (1720-1793) and the continuation of the polemic
93 Roger 1993, 497-511, 692-717; Bernardi 1986, 409-415; M & R 1986, 30-52; Roe 1982, Farley 1977, 22-27; Castellani 1971.
9 4 Castellani 1992, 1991, 1973, Farley 1977, 25; R ostand 1943, 50-73; Bulloch 1938, 75-79; Singer 1934, 460-461.
with John T urberville N eedham (1713-1782).^5 Some historians followed old Clifford D o b ell’s and Emile G uyénot’s judgm ents on N eed h am ’s work. The animalcules, infusoria and microbes “gave occasion to fancy speculations and to the erroneous observations o f a N eedham ” .96 But other historians have tended to justify
N eed h am ’s views by arguing that his criticisms towards
Spallan zan i’s experim ents on the generation o f the anim alcules were actually well-founded. N eedham objected to Spallanzani that, when heating the sealed infusions, such a way o f experimenting destroyed also the internal air, thus impeding any generation of the an im alcu les.97 S. Roe and Mazzolini and Roe later have shown that philosophical conceptions also influenced the debate: Bonnet and Sp allan zan i’s opposed to N eed h am ’s representations of life and its origins were rather incompatible, the form er being
influenced by a preform ationist-m echanistic view, and the latter by an ato m ist-v italist c o n c e p tio n .98 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. H istorians hardly have m entioned and described the works of H einrich A ugust W risberg (1739-1808), of O tto-Friedrich M üller (1730-1784), and W ilhelm von G leichen (1717-1783) who repeated N e ed h a m ’s experiments, in defense o f the
tran sm u tatio n ist generation of inferior be in g s,99 to say nothing of the scores of scholars who had brought small empirical
9 5 See M &R 1986, 30-52; Roe 1983, 1982, Farley 1977, 22-26; Grm ek 1971. 9 6 G uyénot 1941, 442. See also D obell 1932, 380. This judgm ent was how ever softened by C astellani 1969, 215-221.
9 7 S inger 1934, 461. R ostand (1943, 72-73) show ed that P asteu r argued in a sam e way and ju stified N eedham ’s criticism s. See also B ernardi 2000, 54-56 and R oger 1993, 697.
9 8 M &R 1986, 10.
9 9 Stefani 1999, 329, Ruestow 1996, 261, 270-272; D e M artin 1983, 81-84; R ostand 1943, 47.
contributions to the issue. Im portant spread o f their works could act as a relevant reason explaining why the spontaneous generation apparently acquired so wide an audience at the end o f the century, since it was a theory also defended by important authors like
E rasm us Darwin and Jean-Baptiste de L a m a r c k . Yet very seldom are the studies such as A in sw o rth ’s which in 1976 reconstructed an episode of the transm utationist debate betw een Linnaeus, Baron von M unchhausen, and the British naturalists, a dispute dealing with m icroscopical observations made on some spores o f Fungi taken for an im alcu le’s e g g s.i^ i
The study of the theories of generation, of embryology and of p refo rm atio n ism also supplied historians with other argum ents against the scientific value of the microscope. Elizabeth Gasking argued that the m icroscope indirectly strengthened the
p refo rm atio n ist’s views by embodying tiny structure invisible to the naked e y e . 102 The m icroscope then encouraged “fan cy ” dev elo p m en tal interpretations such as those by p reform ationists who claimed that the body already existed as a whole in the
g e r m . 1 0 3 Through the example of sperm atology, Joseph N eedham set m any examples, from François de Plantade (1670-1741) to G autier d ’Agoty (1717-1785) of the im agined m en and horses “observed” with the microscope and folded up in the
s p e r m a t o z o i d s . 1 0 4 Thus the m icroscope is considered as having encouraged a kind of perverse effect on the theory. It
strengthened, according to historians, the b elief that invisible
1 0 0 R uestow 1996, 275-276; Farley 1977, 38-45. K ant considered spontaneous g eneration to be im possible (S olinas 1969, 190).
101 A insw orth 1976, 23-25. 102 G asking 1967, 45-46.
103 F or later developm ent o f the germ theory, see F antini 1994, 111-115. 104 N eedham 1959, 205-206.
structures existed which reinforced some scholars in their views. Invisible structures were used to prove what the scholar wanted them to prove^o^ —the truth of their own theories— ignoring or neglecting the necessity of observations. W alter B ernardi pursued this line of reasoning further by charting a frontier betw een two visual regimes, of weak and of strong visibility. The former describes a way of observing in which the m icroscopical
observations are influenced by theoretical assum ptions. 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 cham pioned by W olff accounting for the early development of the c h ick en ’s blood v e s s e l s . 1 0 6 g o 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 t h e o r y . ! 0 7 Nevertheless Roe also showed that the epigenesists used such a top-down —weak v isibility— approach when exam ining m icroorganisms: “In M arch 1748 B uffon and N eedham started to test the hypothesis that both spermatic
anim alcule and all m icroorganism s were only m achines emerging from a random com bination of organic particles, a theory
suggested by B u f f o n ” . 1 0 8 Both presented in 1748 and 1749 two interpretations accounting for the origin of anim alcules: 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 anim alcules” , and N eedham built a theory of the
Roe 1981, 84; Bracegirdle 1978a, 12.
106 M onti 1990, 183-189; Roe 1981, 60-61; J. Needham 1959, 22. 107 B ernardi 1995, 33-34.
transm utation from the vegetable to the animal. Partly through these exam ples historians have drawn the conclusion that
m icroscopy, during the Enlightenment, was in a state o f regression by comparison with previous studies by L eeuw enhoek who had indeed established the animal nature of both infusoria and
sperm atozoids. But the episodes of the 1740-1760 period radically 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 a m a te u r’s r e a c h ” . ! 0 9
If many studies have embraced the question of the origin of infusoria around N eedham and Spallanzani, there are how ever alm ost no studies devoted to the history of the systematic of
infusoria, and to their m icroscopic determ ination and description. H isto rian s p ro b ab ly recorded some e ig h teen th -cen tu ry scientific discoveries regarding the structure and life o f “anim alcules” : the contractile vacuole of Protozoa recognised by Louis Joblot in 1718, the discovery of free-living amoeba in 1755 by Rosel, the
identification of diatoms by M üller in 1773, and the property of reviviscence o f the r o t i f e r . ! g m actually one can not consider that the extant references and m ethodology hold the key bringing to a systematic inquiry on the history of infusoria. An example of such indistinctness o f the research sharply stems from the
question of the discovery of the division in infusoria (fission). D obell considered L eeuw enhoek to have d etected the reproduction of Volvox; John Baker has held Trembley, in 1744, to be the first discover of the division of unicellular beings; R ooseboom looked
!0 9 R oger 1993, 195.
! ! R uestow 1996, 261-262; R othschild 1989, 279; B racegirdle 1978, 12; Van der Paas 1973, 110; Rooseboom 1956, 56; Cole 1926.
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 N eedham and that of H.-B. de Saussure (1740-1799), one o f the Genevan intellectual heirs of Bonnet, while other historians have ascribed the discovery to Lazzaro Spallanzani in 1 7 7 6 ! ^ Obviously the subject calls for further inquiry.
As a consequence, except for L eeu w en h o ek ’s contribution about i n f u s o r i a , 112 we actually know more things regarding the history of words such as p r o t i s t a and i n f u s o r i a than the history o f 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 Systerna N a t u r a e The word P r o t o z o a seems not to belong to the Enlightenment, having likely been created in 1817 by Georg A. Goldfuss in Ueber der Entwicklungsstufen des Thiers
Infusoria itself appeared “during the latter h alf of the eighteenth- century (...). The “infusion anim als” of M artin Ledermiiller, or the (latinized) “infusoria” of Heinrich August W risberg, m ade their debuts in the early 1760s to describe m icroscopic organisms that appeared in i nf usi ons” . H o w e v e r , almost all the classical
know ledge about the systematics of infusoria in the eighteenth- century takes its source from works published in the first part of the n i n e t e e n t h - c e n t u r y , such as Histoire naturelle des zoophytes i n f u s o i r e s by Dujardin (1841). He identified the main steps in the progression: John Hill was, in 1752, the first to give Latin names to the anim alcules, Linnaeus grouped them under the appellation of
L enhoff and L enhoff 1986, 13; M &R 1986, 39-40; C astellani 1971, 8; Roseboom 1956, 48; B aker 1952, 155-162; D obell 1932, 380.
112 Ford 1991, 38-47; Bulloch 1938, 22-30; Dobell 1932. 113 G uyénot 1941, 91.
114 R othschild 1989, 279; D obell 1932, 378. 115 R othschild 1989, 278.
Chaos, and Otto-Friedrich M üller in 1773 and 1786 systematically classified 379 in f u s o r i a l W ithout being more investigated, this view was popularised by the first handbooks of history of natural sciences, by Cuvier, and Hoefel.^^^ Even the most popular Larousse dictionary of 1880 copied out D u ja rd in 's g e n e a l o g y , i a topic to which some precision was brought by Cole in 1926 and Bulloch in 1938.^19 Cole corrected for instance the date D ujardin attributed to Jo b lo t’s first observations of animalcules (1718 instead of 1754). Bulloch also gave Joblot —him self a whole chapter in the history of infusoria— a respectable place in the history of
p ro to z o o lo g ic a l r e s e a r c h . Yet historians seem unable to imagine suitable means to analyse the problem represented by the creation of the systematics of infusoria between 1773 and 1786, when not ignored: “It is well known that Leeuwenhoek published figures of four forms of bacteria, and Otto M u ller’s work on infusoria,
published in 1786, did contain bacterial forms, but the systematic study was not taken up until the 19th-century” .i2i Chapter 6 will reconstruct the system of sources showing the existence and
importance of M u ller’s works, as well as those by his predecessors. Indeed their comments on such a fundam ental 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 C hristian G ottfried E hrenberg (1795-1876). H istorians usually have stated that Müller, in his 1786 A n i m a l c u l a infu so ria
^ ^ ^ D ujardin 1841, 3-11.
117 C uvier 1845 V, 271-272; H oefel, 1873, 249-250. Carus (1880, 455) who praised M üller, ignored the attem pt by H ill.
11^ L aro u sse 1880, 690, entry “In fu so ire ” . 119 B ulloch 1938, 37, 171-172.
120 B ulloch 1938, 70-71. See also van der Pass 1973. 121 T urner [1967], 175.
co n fo un d ed worm s, pro to zo a and m etazoa,!^^ 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. Au re lia A' ^^ H istorians have sometimes identified the im provements o f the classification from those by Hill and Linnaeus until that of M ü l l e r . 124 So that the same cliché, which after all is said and done seems a badge to be classified “historian of m icroscopy” , 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
r e s e a r c h ” . 125 And why did this programme not develop? Following Bulloch, Dobell, and Corliss, Ruestow has recently considered that “M ü lle r’s achievem ent hence stands alone among eighteenth-
century studies of m icroorganism s, and, since he lacked immediate heirs of significance, such efforts had come to a halt by the
opening decades of the following century” . 126
I will here draw attention to a contrast between “studies” on M üller and the infusoria which almost did not round the cape of allusions, and studies on Leeuwenhoek. Both scholars lacked “imm ediate 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
122 R uestow 1996, 276-277; R othschild 1989, 278-279; C orliss 1986, G uyénot 1941, 91; Singer 1934, 357; D obell 1932, 376.
123 G uyénot 1941, 90. R othschild 1989, 279.
124 Ruestow 1996, 276; Bulloch 1938, 36-37; D obell 1932, 375-378. 125 R uestow 1996, 276.
126 Ruestow 1996, 277. See Corliss 1986, 476; Bulloch 1938, 29; D obell 1932, 3 7 5 -3 8 2 .
difference, perhaps a discrim ination betw een studies on
L eeuw enhoek and on Müller. The bicentenary of the publication of the posthum ous Animalcula infusoria by O tto -F ried rich M üller gave rise to a... four pages paper in the Jo urn al o f pro to zo o lo g y ,
though M üller is the founder of the systematics o f infusoria betw een 1773 and 1786.^27 jn the symposia on the history of protozoology (issued in J H B 1989), no study was dedicated to Müller, though he was hailed there as the D an ish L i n n a e u s Still historians take alm ost always directly their m aterial from good old classics History o f Protozoology by Francis Cole (1926), D o b ell’s
Little Anim als (1932)1^9 and Bulloch’s History o f Bacteriology
(1938). Such a m ethodology is somewhat surprising, because of two aspects: on one hand there are practically no historical studies about M ü ller’s works, as compared to Leeuwenhoek; on the other hand, as we will see in chapter 7, the historical knowledge from the 1840s onwards took gradually into account only L eeuw enhoek and se v en teen th -cen tu ry m icroscopy. Indeed, when com paring data on Leeuwenhoek and Müller during the 1840s with the present state of our knowledge, one is lead to think that the h istoriography about M üller and E n lig h te n m e n t’s m icroscopical research is more than one century b e h i n d the history of
seventeenth-century m icroscopy. For 150 years, historians have studied L eeuw enhoek and alia, and for 150 years eighteenth- century microscopy has been neglected. As a consequence, 1 dare say that one of the functions of the classic historiography of m icroscopy has mainly been to explain the “absence” of
127 C orliss 1986.
128 R othschild 1989, 278. C hurchill (1989, 188) ju m p e d from L eeuw enhoek to L am arck and then E hren b erg .
microscopy. But such an absence, in a high proportion, is the
product of the lack of interest in eighteenth-century m icroscopy — not in the m icroscope— stemming from the previous
historiography... So that we are lead to the conclusion that a part of this historiographical trend has especially functioned as an
o b s t a c l e to someone undertaking research on the period. Perhaps also the im portance of spontaneous generation has taken a heavy toll, for, oddly enough, such a big hole in historiography
represented by the ghostly E nlightenm ent m icroscopy coincides with the m ajor period in which spontaneous generation was mainly discussed by scholars. Eventually “m icroscopy” 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 E n l i g h t e n m e n t . % shall negate, along with the cliché, the object itself of the standard history of microscopy, and my study shall thus reconstruct the European netw ork of practices o f scholars who used the m icroscope.
It is not easy to break down so rooted a prejudice, and
contem porary historians are from two decades confronted with quite similar a situation to the one eighteenth-century scholars