The true identity of Pascal’s mite and the diachronic use of ciron

The identity of Blaise Pascal’s mite is examined. Linguistics, morphology, habitat and size reveal that Pascal’s mite is not Acarus siro L., as usually thought, but Sarcoptes scabiei (L.). The diachronic use of the popular term ciron is explored from a number of different perspectives. In everyday language and in Pascal’s time, the term used to designate A. siro L. was mite (used singly, in English and French) and not ciron, a word restricted to the scabies mite; its use is also investigated. The classification of mites in the 17th and 18th centuries is reviewed.


Introduction
Blaise Pascal's Pensées was published, after his death, in 1670, but was written at an epoch when the microscope became a recreational tool for laypersons (Armintor, 2011). It was also drafted at a time when the concern for scientific rigor combined with an amazing freshness and austere piety (Bouvier, 1996). Pascal (1623-1662 was completely educated by his father and is considered a child prodigy. When he was eleven, he delivered a thesis about the beginning and discontinuation of sound and, at sixteen, he wrote an essay on conic sections. This "effrayant génie" ("scary genius"), as named by Chateaubriand (1802), is renowned as a mathematician (early pioneer in the fields of game theory and probability theory, Pascal's triangle), physicist (the unit of pressure, the pascal, is named after him), inventor (the pascaline is the world's first fully functional mechanical calculator), philosopher (Pascal's wager) and writer. Nowadays, he forms part of the French Baccalaureate Literary Study Program.
Although it is not an acarological book, Pascal's Pensées is of interest to acarologists as he illustrated the infinitesimally small with the familiar ciron, the French word used in the past to designate a mite: "Qu'un ciron, par exemple, luy offre dans la petitesse de son corps des parties incomparablement plus petites, des jambes avec des jointures, des veines dans ces jambes, du sang dans ces veines, des humeurs dans ce sang, des goutes dans ces humeurs, des vapeurs dans ces goutes…" (Pascal, 1670: 173-174, translation by Boitano (2002: "Let a mite show him in its minute body incomparably more minute parts, legs with joints, veins in its legs, blood in the vein, humours in the blood, drops in the humours, vapours in the drops…"). Pascal's mite is abundantly cited in recent books: Espagnat (1986), Morali (2004), Jacquard (2004), Onfray (2014), Godin (2016), from astronomical to philosophical works.

Material and methods
The true identity of Pascal's mite is elucidated by consulting the 16 th and 17 th century dictionaries and encyclopedias, i.e. primary sources. Incunables, books and other documents published at that time, or issued earlier, were also scrutinized. Electronic versions of publications were used, for instance from the Bibliothèque nationale de France. The optical character recognition (OCR) was used whenever possible. Due to lack of space, some references are not given; for instance, Mersenne, Pascal' mentor in the sciences, cited at least 4 times the ciron, but only one reference is mentioned.
There may be marked differences between successive editions (e.g. Malebranche, Mellema, Montaigne). Therefore, the editio princeps or the oldest available edition was preferred. Variants differed depending on the epoch, language and countries: ciron, cyron, süren, syrones… the original noun was maintained. The term ciron also is a patronymic, a French commune, a river… The meaning may be affected by regionalisms: "cironné" sensu "wormeaten" is a typical helvetism (Rey, 1998); this regionalism does not apply to cheese crust.

Results
Results are presented in four parts. The first and longest concerns the vernacular term and its variants, ciron (glossaries and dictionaries of the 16 th and 17 th centuries, the diachronic meaning of the word ciron, its metonymic use, its origin, its popularity, and its symbolism). The second domain involves tle medical word syrones and its variants (the school of Salerno, the school of Montpellier, other approaches). The last parts are devoted to the cheese mite and the classification of mites in the 17 th and 18 th centuries.

A popular approach
French glossaries and dictionaries of the 16 th and 17 th centuries Pascal was not an acarologist, nor was he a physician as were Bonomo and Mouffet. How did French dictionaries of the time define a ciron? All French dictionaries of the 17 th century took the term ciron, from the Nicot's Thresor de la langue françoyse, a document that played an important role in the development of French lexicography, to the 1 st edition of the dictionary published by the French Academy. They all described the habits of the scabies mite (Table 1). The inclusion of the word ciron in the dictionary released by the French Academy is highly interesting as the dictionary banished terms which rarely entered the spoken language (Ernst, 2015: 87). Technical terms were considered disgraceful and relegated to Le Dictionnaire des Arts et des Sciences compiled by Thomas Corneille (Rouleau et al., 2006).
Even better, the bilingual dictionaries of the previous century also reported the term ciron and, from 1650, again referred to the scabies mite (Table 2). Last, Power (1663: 22), an English physician, Rohault (1671: 145), a French physicist, and Ozanam (1694: 162), another French mathematician and also popularizer, even stated that the ciron had the back covered with scales, a feature that definitely excludes the cheese mite with a smooth back.
The diachronic meaning of the word ciron In medieval Europe, glossaries with equivalents for Latin words in vernacular or simpler Latin were in use. Over the course of the 16 th century, successive Calepino's dictionaries were published, originally as a monolingual Latin work, and then enlarged to become multilingual glossaries. The French term ciron was then a simple translation of the Latin acarus and the translation resulted in a synonymy between the two terms. The translation applies also to the Old German seuren (cf Frisius, 1616: 8).
In Pascal's time, Sarcoptes scabiei was common and received many vernacular names
Finally, ciron meant all mites. The famous French popularizer, J.-H. Fabre, still used ciron to designate mites in one of his best-known books (Fabre, 1875). Within a syntagma, it may refer to a specific mite: for instance, the Ciron rutilant des savanes was identified as a Trombicula sp. by Marc André, a founder of this journal (Sevenet, 1936: 60) and the expression is still used today (Euzéby, 2008: 14). Other recent examples of syntagma are provided by Loschiavo (1984), Mills (1990) and Loiselle (1999). The examples above illustrate the transition from a monospecific assignment of the word ciron to a widest use. A similar transition is also observed with the Greek noun ἄκαρι used by Aristotle.

The popularity of the word ciron
Pascal was not the first and only philosopher to use the ciron to illustrate his ideas. In the previous century, Montaigne used the mite image twice (no citation in the first edition of his essays published in 1580, once in the 1588 edition, twice in the posthumous edition). It was perhaps by reading Gassendi (1592-1655) that Pascal adopted the mite image to illustrate the infinitesimally small (Rochot, 1944). Indeed, the term ciron was abundantly cited by Gassendi (Bernier, 1678: 66, 143, 145, 163) and his observation was even reported by dictionaries (see La Furetière in Table 1). Du Roure (1654: 17), Malebranche (1674Malebranche ( : 41-1677, and La Grange (1682: 42) were other philosophers of Pascal's time citing the mite. An alternative approach, also initiated in the 16 th century, consisted of comparing the ciron to the elephant or to another big animal: Bodin (1577: 9), Montaigne (1588Montaigne ( , 1598, Descartes (1647), La Bruyère (1699: 453-454) and more than 30 other authors of this time.
Actually, the term was very popular in France and had already appeared in the previous century, for instance in famous Rabelais' novels: "Enay qui fut tres expert en matiere de oster les cyrons des mains" (Rabelais, 1532: 11). The English equivalent depends on the translators: "Who begat Enay, who was very expert in taking the little Worms out of the Hands" (Smith, 1893: 213) or "Who begat Enay, the most skilful man that ever was, in matter of taking the little worms (called cirons) out of the hands" (Urquhart and Motteux, 1935: 292). The word ciron was repeated in Le tiers livre published in 1546 and in Le quart livre released shortly before his death. The term is also found in a poem by Ronsard (1557: 35), sometimes called the 'prince of poets': "Un ciron qui souvent entame / La peau doüillette de ma-Dame". What is noticeable is that both authors, Rabelais and Ronsard, referred to the scabies mite and not to the cheese mite.
The term was featured in Les Folles entreprises released in 1505 by Pierre Gringore, poet and playwright (Héricault and Montaiglon, 1858: 35) and in Le droict chemin de musique by Bourgeois (1550), composer and music theorist. The Latin equivalent was also used by Scaliger, a philosopher and man of science who spent a major part of his career in France, and synonymies were given: "Acaris. Garapates. Pedicellus. Scirus" (Scaliger, 1557: 600). It was contained twice in the collection of proverbs proposed by Meurier (1557: n.p.). In Le Blanc (1556: 198;1578: 147), ciron translated the acarus used by the Italian polymath Gerolamo Cardano in his De subtilitate rerum published in 1550 (Cardano, 1663: 515). Lastly, the term appeared in works as different as the history book by Crespin (1555: 113), the book on astronomy by Girault (1592: 6), the treatise on wines by Paulmier (1589: 52), the textbook on agronomy (Serres, 1600), the fictional work of the novelist Béroalde de Verville (1612: 184), the comprehensive works on music theory written by Mersenne (1636: 184), and La Fontaine's Fables (La Fontaine, 1668, 1678. Romeo and Juliet, the tragedy completed by William Shakespeare in around 1595, evoked the scabies mite: "Not half so big as a round little worm / Prick'd from the lazy finger of a maid", an interpretation defended by Keil (1957).
The term remained current in the 17 th century. It is used in the correspondance of Nicolas

The symbolism of the word ciron
In his seminal text, Pascal (1670) illustrated the infinitesimally small with the ciron which remains today a living symbol of smallness. An eloquent example is offered by Grousset's (1942) translation of the Zhuangzi, a Chinese canonical text: "un ciron vaut une montagne" (the term wén, opposed to the mountain, is usually translated by mosquito). In the 17 th century, such a sense is common and the smallness of cirons was alluded to by numerous authors who were not physicians: Battista (1529: n.p Another close sense is found in texts written by poets (Baudelaire, 1857) and philosophers (Alain, 1931;Sartre, 1942) who stressed the insignificance or the meanness of man. Diverse negative connotations are perceived in Apollinaire (1911 -"Regardez cette troupe infecte / Aux mille pattes, aux cent yeux / Rotifères, cirons, insectes"), Le Clezio (Nobel Prize in Literature-1965 -"Lourde citerne d'eau stagnante où couraient les cirons et les moustiques") and many others.
The remark of the French chronicler Brantôme (ca 1537-1614) is outstanding: "Le cas d'une fille est fait de chair de ciron ; il démange toujours ; et celui des femmes est de terre de marais, on s'y enfonce jusqu'au ventre" (Brantôme, 1881). Around the same period, this erotic symbolism was copied by Tabarin (Duneton, 2014). Such a symbolism associated with the itch mite was already present in Rabelais and in Cotgrave's dictionary (Screetch, 1995: 179). Lastly, the ciron evoked by Breton (1973: 116) is strangely reminiscent of the statement of King James I of England (1566-1625) who has the credit of having declared that "none but kings and princes should have the itch, for the sensation of scratching is so delightful". A similar allusion is found in the old French song "J'ai un ciron sur la motte" (ca 1475-1480 - Tacaille, 2015). Although King James' remark is associated to scabies (Wilson, 1865: 112;Lyell, 1976: 119;Currier et al. 2012: E50), a reference to Pthirus pubis may not be excluded: the itch-mite is frequently mentioned with lice in old textbooks but the difference was already stressed by Mouffet (1634: 266).

The medical approach
Even if the history of scabies is fascinating and controversial (Ramos-e-Silva, 1998: 625), it is beyond the scope of this article. Just as an example to illustrate the importance of scabies, in Paris around 1850, 250 to 300 sick people went everyday to the Hôpital Saint-Louis where those suffering from ringworm and scabies were treated free of charge (Le Quellec, 2000). Seriously affected scruffy individuals were admitted to a special service providing 60 beds for men and 15 for women (Feulard, 1886).

The school of Salerno
Scabies, important for the 19 th century hospital management, was obviously not ignored in the medical world of the Middle Ages. Syrones appeared in the Trotula, the most influential compendium in medieval Europe, presumably written by Trotula of Salerno (11 th or 12 th century), alleged to be the first female professor of medicine at the medical school of Salerno (Italy). The book comprises three texts written in Latin; these three popular texts survived in more than 100 manuscripts, were assembled and printed by Kraut in 1544 (editio princeps) and were again edited and translated by Green (2001). In De ornatu mulierum, there is the following passage: "Ad syrones rodents capillos…et inde capillos frica inter manu. Hoc syrones expellit et occidit". Green (2001: 175) translated this way: "For itch-mites eating away at the hair…and then rub the hair between the hands. This expels itch-mites and kills them" (Green, 2001: 175). This passage probably refers to a head lice infestation and not to a mite. It is, however, indicative of the difficulty interpreting old medical texts. As already commented by Oudemans (1929: 704), the section dealing with scabies is short (2 lines) and did not refer to an animal. However in the 1550 edition, named Trotulae curandarum aegritudinum muliebrium ante, in, & postpartum Liber, syrones are cited "vermé de manibus & pidibus" (Trotula, 1550: 36).

The school of Montpellier
Quite different were the syrones described in the Chirurgia, also written in medical Latin, by Henri de Mondeville, royal surgeon to French kings Philippe the Fair and Louis the Stubborn: the text, composed between 1306 and 1320, clearly referred to minute animals boring between skin and flesh (Nicaise, 1893: 635).
Guy de Chauliac, who succeeded him in Montpellier (France, the world's oldest medical school still in operation), also stipulated that syrones were small animals, living between "carnem, & cutem" especially on the hands and evoked the contagious nature of syrones in his Chirurgia magna composed around 1363 (Humphery- Smith et al., 1990). The Mal Latin -and the terms syrones or sirones -remained in vogue for several centuries and these terms were still found in Plenck (1776). These animals became cyrons or cirons in subsequent  (1893) and Gombert and Chevalier (2006). Another consequence of Chauliac's Chirurgia magna was the introduction of ciron into Middle English (Kurath, 1959: 280-281). Altough it is obsolete, the word is still found in the Oxford English Dictionary. Guillaume Rondelet, also professor of medicine at the University of Montpellier and teacher of François Rabelais, evoked the cyrones living "semper intra cutim & cuticulam" (Rondelet, 1573: 10) and the women extracting them with a needle (Rondelet, 1573: 11). The syrones, i.e. Sarcoptes scabiei, were also well known in Pascal's time and were mentioned by Platter, a medical student in Montpellier in the previous century; the Swiss physician wrote: "Hos Sirones Germani Súren appellant, rectiùs fortè Chirones, cùm manus occupent" (Platter, 1608: 966). Pascal was 11 years old when they were studied by Mouffet (1634: 267-269) who cited Aristotle (and alluded to "cafeo & cerae"), mentioned his predecessors (Avinzoar, Gabucinus), described their habits, and scripted "Animalculū est omnium minutissimum". The renowned German physician Sennert (1634: 118) referred to sirones or chirones, also called seuren and moreover indicated that, for the most part, they are extracted with a needle (Sennert et al. 1661(Sennert et al. : 2486. Borellus (1656: 16-17 [observatio XXI], 21 [observatio XXXII]) used a microscope to refer to vermiculi associated to scabies and reported turtle-shaped syrones in humans, a shape also observed by the German physician Wichmann (1786: 39) and dermatologists Hebra and Kaposi (1870: 673) (but syrones, which are Acari on page 17 and in Borellus' index, were associated to variolis [observatio XXXI]). Similar confusions with regard to diseases were made by the Polish scholar and physician Jonstonus (1657: 93, 130). In contrast, the syrones "in cute" were appropriately named Wheal-worm, Hand-worm or acarus by the English physicians, Merrett (1667: 206) and Charletoni (1677: 52).

Other medical approaches
Lastly, after the first rough sketches drawn by Hauptmann in 1657 and by Ettmüller in 1682, an illustration was made by Bonomo (1687: end plate) who knew the difference between A. siro occurring in large number in old cheese ("gran numero nel formaggio vecchio" -Bonomo, 1687: 14; fig. 13-15 reproduced in Figure 2) and S. scabiei (his fig. 1-3 also reproduced in Figure 2).

The origin of the word ciron
Two origins were considered by Ménage (1694: 199): either the word derives from the Ancient Greek χείρ (kheír, 'hand') (see also Table 2) or the animal is named after the cire (French name for wax) where it is born according to Aristotle. Michael (1903: 117, footnote) advanced that the medical terms sirones and syrones could derive from the Greek Σίρόσ meaning cavity and be an allusion to the boring habit of S. scabiei.
Following the work of Gutenberg, printing made it possible to popularize manuscripts hitherto copied by hand. The Rommant de la rose written in 1230 by Guillaume de Lorris and completed around 1270-1275 by Jean de Meun was reprinted many times. The verses attributed to the latter, suggest we accept only those who have "mains belles et nettes, ou de cirons ou de bubettes". The examples above attest to the use of the term ciron in Old and Middle French, even before Francis I imposed it as the administrative language by the ordinance of Villers-Cotterêts, in 1539.
Similar words (chiron, sirones…), i.e. derived from the same etymon, were also used in close areas, Germany, Belgium, UK and the Netherlands. For instance, in 1273, sier is for the first time recorded in Middle Dutch, as the plural sieren, in a text from West Flanders (Vaan, 2016). The plural zieren is also found in Die pelgrimage vander menscheliker creature (mid-15 th century) and in Het boeck vanden pelgherym (1486). Pascal's mite was part of a more global language movement involving other European countries.

The cheese mite, another naming in the 17 th century
Acarus siro is not forgotten by 17 th century French authors but is designated by another word, the mite. The term is not in Estienne (1539) but the 1549 edition clearly referred to the cheese mite. Therefore, the two French terms, ciron and mite should not be confused as they designate different species, respectively the scabies mite and the cheese mite. They may however coexist, even in the same sentence as exhibited by the letter of Peiresc of 21 May 1622 (Tamizey de Larroque, 1896).
In the 17 th century, A. siro was usually designated by a single word: mite (French with the derived terms miton, midon), mijt (Dutch), mite (English, noted by Mouffet, 1634: 266), midas (Latin) (references in Table 3). In a letter written in 1622, Peiresc used the words mittes, artisons and mitons to describe mites collected from a piece of cheese (Brunet, 1951). The distinction is still made by Courtin (1824: 50-51). The ciron was rarely associated with cheese (e.g. Monet, 1635: 947;1637: n.p.)   It is noteworthy to remark that the cheese mite is clearly visible to the naked eye while the adult female S. scabiei is only 300-504 μm long (Arlian, 1989), the size of the cheese mite is thus hardly compatible with the infinitesimally small invoked by Pascal. This significant difference in size between the "smallest of Creatures" and the mite observed in cheese was already perceived by Power (1663: 16-17, 22).
Another difference concerns the shape: "the body of the acarus farinae appears to be more oblong than that of the itch insect" (anonym, 1788: 43; see also Geer, 1778: 97), an oblong shape that contrasts with the special turtle shape of S. scabiei as already noted, in Pascal's time, by Borellus (1656: 17).
Nowadays, up to 10 species are identified in cheese, but only 2 are currently inoculated and could be called cheese mite, A. siro and Tyrolichus casei (Melnyk et al. 2010).

Classification of mites in the 17 th and 18 th centuries
If ticks are excluded, mites known in the first half of the 17 th century formed a group limited to 2 species: namely the cheese mite, A. siro, and the scabies mite, Sarcoptes scabiei. Geer (1778: 83) called them 'Mittes' (with two 't', idiosyncratic spelling) and recognized that the species are very different. However, his plate 5 did not illustrate the dorsal scales seen by Power (1663: 22), Rohault (1671: 145) and Ozanam (1694: 162) and typical of the species (Figure 3). Was his microscope so bad? His drawings seem to be so mediocre when they are compared to Goeze's illustrations published by Wichmann (1786) and reproduced in Figure 4.
Many mites were observed during the second half of the 17 th century (pre-Linnean works). For instance, Power (1663) reported mites in dust, in figs, in Jujubes, a red variety on spiders, on humble-bees (genus Bombus, part of Apidae), and in ponds. In 1758, the 10 th edition of the Systema naturae was published by Linnaeus who described 31 species of mites, all in a single genus, Acarus. Under the heading Acarus siro, three species were put together: siro, farinae and scabiei. Provided Geer's domesticus corresponds to Linnaeus' siro, the confusion was cleared up by Geer (1778) but all the mites, discussed under the heading 'mittes', remained in the genus Acarus erected by Linnaeus. The classification was repeated in 1783 but the genus Sarcoptes was established later by Latreille (1802).
In 1775, Fabricius proposed the genus Trombidium for three species (tinctorium, holosericeus and aquaticus), the last two being listed and assigned to Acarus by Linnaeus (1758). The following year, Müller erected the genus Hydrachna. The dismemberment of Linnaeus' genus Acarus had already started as early as the 18 th century and is reflected in Vicq d'Azyr's (1792) classification. Still later in the 18 th century, Latreille (1795) proposed a division into 11 units (e.g. Bdella) and, in 1796, he advanced a final classification (mites were called Acéphales) into 18 genera. A. siro was part of genus 17. Pascal's mite was not mentioned. His ciron referred to the genus Siro, his genus 18, currently assigned to Opiliones and not to mites. Obviously, Latreille's ciron is not Pascal's ciron.

Conclusions
Sarcoptes scabiei lies at the crossroads of two traditions: a popular perspective on the one hand, a medical approach on the other hand. The latter referred to Latin word syrones and traced its history back to Trotula of Salerno (12 th century). The former derived directly from the Franconian etymon seurō already used in the 12 th century by Hildegard of Bingen; Pascal's mite was part of this long popular tradition. Yet both trends were based on the same etymon.
Pascal's mite is an ancient story involving two species, the cheese vs the scabies mite. The identity of Pascal's mite is simply elucidated by consulting the epoch's dictionaries and encyclopedias, i.e. primary sources. Books and other publications published at that time or issued earlier were also scrutinized. In the days of Pascal, S. scabiei was a well-known mite and was designated by the vernacular term ciron. In addition to linguistic arguments, the morphology (scales or spines), the habitat (skin) and the size argue in favor of the scabies mite.
Pascal's ciron is thus the human scabies as written by Morali (2004). The mix-up between the two species, the cheese and the scabies mite, was made by Goeddart (1662: 125), continued in Linnaeus' successive publications (cf. Oudemans, 1913), in Fabricius (1775: 812) and triggered the gallic affair in Paris, usually presented as a scientific fraud perpetrated by a student named Galès in his medical thesis in 1812 (Janier, 1994;Ghesquier, 1999;Ghesquier-Pourcin, 2011). The confusion was also maintained in the 8 th edition of the Dictionnaire de l'Académie française (1932) that explicitly referred to cheese and flour (but not in previous editions) and reproduced in Littré's dictionary (1863: 628). It is also found in Rey (1998: 762) and Bonnafé et al. (2014). The famous Encyclopédie edited by Diderot and d'Alembert probably marked a turning point with two entries for ciron: the first entry (natural science) was written by Daubenton (1753: 475-476) and related to the two species while the second one (medicine) was composed by Venel (1753: 476) and dealt only with the scabies mite.
This example illustrates the way that when we look back into the past with modern techniques and equipment (Ratcliff, 2009) and current ideas (Ghesquier-Pourcin, 2011). There is a growing risk of bias in the future, especially when the principle of priority is to be respected.