Cochineal, Kermes and Coccus between ambiguous organisms and hermaphrodites

The small organism named cochineal was imported into Europe since the conquest of Mexico, where it was used for dying textiles by the natives. In Europe, its arrival reduced the use of Kermes^g (Coccus ilicis) and the importation of Coccus polonicus which had come from Poland, as well as other plants like lichen which were previously used for dying.³⁰¹ The Spaniards rapidly mastered the techniques of the new world for production and transport in the former Aztec empire. Among other methods, cochineal was smoked and dried in the sun, a technique that proved itself to be highly efficient in avoiding putrefaction even when shipped across the Atlantic. Boats mainly landed in the southern part of Spain, from where goods were dispatched to the old continent, and sold by apothecaries. Arriving in Europe as a dried grain of a size between a grape seed and a grain of pepper, the cochineal was considered by many people, including some naturalists, to be the seed of a vegetable not yet described. The problem of its nature, vegetable or animal, began to be discussed in the 1670s with the microscope on hand, in Italy, Britain, Germany and France. In England, after research by Martin Lister (1638-1711) of the early 1670s, the question mostly turned on a 1691 report published in Philosophical Transactions by a Spaniard, in which he alleged that the presumed dried grains were nothing more than insects.³⁰² Evidence was mainly supplied by citing the two procedures used by indigenous people of killing insects by fumigation and drying them under the sun so as to transform their appearance into that of a vegetable seed.

In Italy, and more precisely in Tuscany, the general interest in defining the varieties of methods of reproduction lead scholars to consider insects such as lice and Kermes.

Though Redi demonstrated in 1668 that insects hatched from eggs, there remained some doubtful parts of the theory, such as the origin of the oak gall louse which Redi

301 De Jaucourt (1777 XIX, 1022) said in Encyclopédie, “The use of cochineal ruled out every dye that could be supplied by plants.” See also Nissole 1717, 441, and Hill 1752a, 5.

302 An. 1691, 503.

attributed to a vegetable soul.³⁰³ Malpighi’s criticisms drove Redi to change his mind, and an important question emerged out of this quarrel: was it possible to find insects that were both viviparous and oviparous?³⁰⁴ During the 1680s, Diacinto Cestoni observed lice and their lack of mating habits, and compared it to other insects such as Kermes. In November 1689, he wrote to Redi about the discovery of the eggs of Kermes.³⁰⁵ Probably through private correspondence, the thing came to be known, and such exception to a rule considered general excited the scientific world. In 1693 the French academicians Philippe de la Hire and Sedileau, quoting the works of Redi, studied the louse of the orange tree and showed that it was an ovipara with sexual differentiation though they considered that they should mate “when they were young, and before they were fixed to the tree”.³⁰⁶ At the end of the year, La Hire described a microscopic spider that lived as a parasite on the common flea, considering he launched thus a field of research untouched by Redi.³⁰⁷ Probably during that period, La Hire observed the cochineal and took it for the dry trunk of an insect, but Fontenelle did not give further precision about the period of La Hire research.³⁰⁸ Leeuwenhoek begun his own works on the louse of the orange tree and on the cochineal in 1695, having

probably been influenced by Redi, La Hire and Sedileau.³⁰⁹

Around 1704, the debate over exceptions in mating became topical throughout Europe.

Several sites saw involvement in investigating the question, in Paris, in Holland, in Italy and in England. Philosophical Transactions served Leeuwenhoek in dealing with a public different from the French, for whom La Hire and Nicolas Lemery (1645-1715) were discussing the issue. Leeuwenhoek referred to the previously mentioned paper by

303 Redi 1668, 146-147. In 1683, Cestoni also wrote to Redi against the vegetable soul (Baglioni 1940, 94-95).

304 Redi 1684, 71. The question was recalled by Geer 1772, 43ff.

305 Baglioni 1940, 32.

306 La Hire and Sedileau 1730, 13-14.

307 La Hire 1730, 425.

308 Fontenelle 1706, 11.

309 On Leeuwenhoek’s work on cochineal see van Seters 1962, 98.

the Spaniard with whom he shared some claims.³¹⁰ Through microscopical observations and microdissections, and also inspired by La Hire’s view, Leeuwenhoek propounded that the cochineal of the new world was a part of an insect, a mere trunk deprived of its wings and feet. People of course continued to consider cochineal to be a vegetable seed.

In fact, around 1704, Leeuwenhoek had had an argument with an Amsterdam merchant, who claimed that the cochineal was not an insect, arguing that there were not enough people in the new world to catch and dismember the amount of cochineal that a single ship could transport to Europe.³¹¹ Leeuwenhoek reaffirmed his belief that “Cochineel is nothing else but the trunk or hind part of a living creature”.³¹² From the anonymous Spaniard’s paper, he quoted the technique used by Jamaicans for refining the desiccation of the insects. The cochineal were “rubb’d between the hands, till their wings, legs, etc. fall off, which are garbl’d out, and then the remaining trunk of the animals are put into shallow copper boxes, till they become quite dry”.³¹³ In order to refute the merchant’s view, Leeuwenhoek gathered several “grains” of cochineal of various origins, and began to repeat the microdissections.³¹⁴ He found eggs in the bellies, up to 200 in the larger specimens, the first indication of their animality.

However, in his view, he was not dealing with a whole insect, but only with its trunk.

He drenched the organism with water, having “soakt their trunks thoroughly”.³¹⁵ Getting to the crux of his microscopical observation, he added that even the head was gone, such that the common cochineal of apothecaries was but a mere trunk of an

310 Leeuwenhoek 1704 quoted him on pages 1615-1616.

311 Leeuwenhoek 1704, 1614.

312 Leeuwenhoek 1704, 1615.

313 Leeuwenhoek 1704, 1616.

314 Ruestow (1996, 205-206) has related this work by Leeuwenhoek to the micro dissections performed by Malpighi and Swammerdam on the sexual apparatus of insects.

315 Leeuwenhoek 1704, 1619 (the pagination is wrongly 1615).

insect.³¹⁶ As usual, a draughtsman collaborated with Leeuwenhoek after he had prepared a microscope. From the microdissection of a cochineal soaked in rain water

316 Leeuwenhoek 1704, 1620.

for 24 hours he drew microscopical pictures of cochineal’s eggs, their anatomical parts and embryos, some of them with legs. (Fig. E)

There are two theses in Leeuwenhoek’s paper which are of interest to the history of microscopical entomology, and which reveal his way of working. The first relates to the nature of the cochineal and the second concerns its generation. The important fact is that both opinions were later rejected, and they became symbolic of the Dutchman’s limitations when involving himself in the microscopical investigation of nature. The first thesis argued that the common cochineal of apothecaries was the trunk of an insect, and not a whole insect. Arguments supporting the vegetable nature of the cochineal met perhaps with favour in the Royal Society but no further discussion was published. The vegetable theory was partly discarded in the academic world though not with sufficient evidence; Leeuwenhoek however referred only to the Spaniard’s paper. He did not mention anyone else who had previously studied the cochineal, and there is no special mention nor discussion of any previous research carried out at the Académie des Sciences, in Germany or in Italy, showing the cochineal to be a whole insect or a mere trunk. Indeed, though the trunk thesis had first been expressed by La Hire, it was Leeuwenhoek, and not La Hire, who would later be rejected from the entomological tradition, most probably because of his tendency of not citing previous papers by other scholars.

The second thesis was aimed more closely at the academic world, or, expressed more clearly, to the representation of the academic world according to Leeuwenhoek, and exclusively concerned the generation of cochineal. He did indeed observe that several species of flies did not need to mate in order to breed offspring, in other words they were parthenogenetic species. In the same paper, he began to oppose his observations to

“those that maintain there can be no animal generated without a copulation of male and female”,³¹⁷ namely Francesco Redi, who had died seven years before, and his many disciples. Had he been able to read their books, especially Redi’s and La Hire’s works,

317 Leeuwenhoek 1704, 1619.

the Dutchman would have known that the parthenogenetic question had been an issue since Cestoni made it one during the late 1680s, providing the end point of seventeenth-century observations of parthenogenetic phenomena in insects.³¹⁸ Nevertheless, in 1704, Leeuwenhoek changed his mind in regards to his previous opinion. His first “aim was to be satisfy’d (as [he] suppos’d) that they were the trunks or bodies of the male flie”.³¹⁹ But the anatomical and morphological identity of the smaller cochineal --thought to be the male-- and the larger cochineal insect induced him to change his opinion, and he was further convinced when he discovered many eggs enclosed in the insects regardless of size.

However, with nothing like the methodological prudence held up as a standard by experimental philosophers, Leeuwenhoek inferred from his observations that the species of cochineal was lacking of males and constituted only by females, because he could not find either male or insect without eggs.³²⁰ Two explanations were supplied to account for this, the one analogical and the other derived from Leeuwenhoek’s

microdissections and microscopical observations. The analogical argument rested on his previous observations of clouds of insects which “infested the leaves of the lime-trees, or those other that were found upon currant trees, cherry trees or hazel-nut trees, all with animalcule bring forth young alive and these young ones being very little, have their bodies fill’d with other young, and are all females, and consequently there is no copulation among them”.³²¹ Leeuwenhoek most likely saw parthenogenetic phenomena

318 In 1714, Cestoni (1715, 161) replicated observations he had made in 1689 on parasitic insects of the willow and wrote them in a letter to Vallisneri, which the latter published in 1715.

319 Leeuwenhoek 1704, 1619.

320 Leeuwenhoek 1704, 1619. John Ellis, in 1762, described the male cochineal in Philosophical Transactions. He used a similar technique of moistening the insect for 24 hours (Ellis 1762, 665). In the second part of the century, the entire story was well known, as written by Daubenton (1778 V, 334) in Encyclopédie, “nowadays there is no doubt that the cochineal is a desiccated insect. We have

incontestable proof of that by the observations made in Mexico, the only country where it is gathered.

However, independently of the facts that have been established on this, we could take the cochineal for an insect, in the condition in which we see it in our country, especially if observing with a lens or a microscope, after being put in water or in vinegar. Thanks to this preparation, we can distinguish in the most formless seeds of cochineal the different rings of which the body of the insect was composed of, and we can find in several of these seeds entire legs”.

321 Leeuwenhoek 1704, 1619.

in lice,³²² but he inferred “consequently” and without empirical evidence that this was also the identical situation for the cochineal, just because he met with it frequently in his dissections. Thus, with the asexual generation hypothesis in mind, he dissected five more cochineal insects under the microscope. On finding unequal numbers of eggs in various stages of development, he wrote: “From these observations I conclude, that the production of the coccineel flies happens after the same manner as that of the

animalcula upon the lime, currant, plumb and hazel-nut trees”.³²³ According to the methodological standards of that time, expressed in Holland in the treatises of s’Gravesandes and Hermann Boerhaave, in order to put forward such an affirmation, Leeuwenhoek should have performed experiments.³²⁴ What was especially lacking in Leeuwenhoek’s work was a sense of modern experimentation, of counter logical experimental evidence and a capacity for following organisms within a strict experimental setting. He will later be criticised on this point by scholars of the next period: by Réaumur, Trembley, Bonnet, and even by Ledermüller.³²⁵ In actuality, Réaumur qualified his specificity in exploring invisible objects: “It seems that

Leeuwenhoek was much better able to see the objects of a prodigious smallness, than those of a sensible size, the small objects being more of his domain”.³²⁶ His was simply an observational and manipulative activity, but, for the relative lack of the sense of experimentation, and of observing “intermediary objects”, he missed making

discoveries to which he was very close. The naturalists, the natural philosophers and the scholars since the time of Redi, Guericke, Boyle and Mariotte repeated that a thesis

322 van Seters 1962, 99 has argued priority be given to Leeuwenhoek over Cestoni because, according to him, Cestoni’s letters were only published in 1733, in Vallisneri’s Opera omnia. But some of them were already published in Venice in 1697 in the journal Galleria di Minerva.

323 Leeuwenhoek 1704, 1624-1625.

324 For a survey of the Dutch reform of methodology and experimentation, see Brunet 1926 and de Pater 1989.

325 In a letter to Réaumur about the polyps discovered by Leeuwenhoek, Trembley writes: “vous verrez dans la lettre de Lewenhock, qu’il a vu d’autres espèces de polypes que nous connaissons, mais qu’il n’en a suivi aucune” (CRT 1943, 145). “Il nous manque un bon examen critique des oeuvres de ce pénétrant et infatigable scrutateur des merveilles de la nature” (Bonnet 1781[1764] II, 21). See also Ledermüller 1764, 72-73.

326 Réaumur 1740, 129.

could be supported through the empirical demonstration that the contrary was impossible.

It was probably not a coincidence that during the same year, 1704, interest in the problem was awakened in several countries, including Holland, Germany and France.

In France, the study of lice and cochineal in the Paris Academy was part of a larger microscopical programme, launched in the late seventeenth-century and parallel to that of cryptogam. Between 1703 and 1706, 1710 and 1714, and 1728 and 1731, many microscopical papers were written describing anatomy, physiology, morphology and the behaviour of several species of insects.³²⁷ La Hire thus came anew to the question of the louse in 1703, coming to consider the absence of metamorphosis and generation through eggs, while a Jesuit from Madrid, Father Alcazar reported at the same time in Journal de Trévoux the method of collecting and breeding cochineal in central

America.³²⁸ In 1704, La Hire carried on previous microscopical observations on

metamorphosis, generation, and speciation of cochineal and lice. By placing eggs of the louse in a cactus Opuntia, he could see the new born leaving such a habitat, and

observed that they could be fertile even eight months after mating.³²⁹ This research explicitly continued that of Redi and addressed issues of both taxonomic groups and reproduction habits of these insects. In Germany as well, physicians were interested in the cochineal, mainly used for dying, and three dissertations for instance were written in Leipzig between 1701 and 1709.³³⁰ Later, the heritage of Redi would still be

acknowledged by the MD Lorenz Heister (1683–1758) in his microscopical observation of the parasites of the fly.³³¹ Nonetheless, such a European trend of studies on cochineal

327 Fontenelle 1705, 16; Fontenelle 1706, 10; La Hire 1706; Poupart 1706; Tournefort 1706, 339;

Fontenelle 1707, 9; Réaumur 1712a, 305; Réaumur 1712b, 400; Fontenelle 1714a, 17-18; Geoffroy 1714, 27-28, Réaumur 1714a, 196-197; Maraldi 1714, 327; Geoffroy 1717, 137; Réaumur 1717a, 105-107;

Nissole 1717, 438-439; Réaumur 1721, 269; Réaumur 1730a, 145-149; Réaumur 1730b, 315-320;

Réaumur 1732, 70; Maupertuis 1733, 227.

328 Alcazar 1704, 168-170. According to Fontenelle 1705, 17 Plumier said that the cochineal bred over the Opuntia in North America.

329 La Hire 1706, 47.

330 Richter 1701; Lang 1704; Paullini 1709, 263-266.

331 Heister 1727, 409.

and related insects did not allow the establishment of clear-cut differences between species, even if La Hire’s experiment demonstrated that cochineal and lice of the orange tree were two different species.³³² Equally the conceptions of ambiguity and

parthenogenetic phenomena were not shaped definitely, and in fact, a general

agreement was not reached among scholars, although no one questioned the relevance of the microscope for such an inquiry. Indeed, still in 1714, so strong was the

disagreement among scholars as to the question of the origin of these organisms, green fly, Kermes, “gallinsects” and cochineal, that the French botanist from Montpellier Guillaume Nissole (1647-1735) could write that “there are almost as many feelings regarding the origin of Kermes as there are authors who have written about it”.³³³ In 1710 a new wave of studies emerged in Italy that later was to reach France.

Vallisneri, in his 1710 Consideration and Experiments on the Origin, Development and Costumes of several Insects, described the louse of the rose and its method of

generation. At Vallisneri’s request, Count Marsigli studied the case of the Kermes on which he published in 1711 a letter to Vallisneri in Venice.³³⁴ There he confirmed, through microscopical observations and chemical analysis, that this insect came from eggs and worms, thus following Malpighi’s interpretation set out in Anatome

plantarum.³³⁵ The Kermes presented a better specimen for observation than the Mexican cochineal because it was available alive in the south of Europe, being a parasitic host of the oak tree feeding on the oak apple. Consequently many naturalists had discussed its nature since the Renaissance. Marsigli’s thesis gave the opportunity to Diacinto Cestoni and Vallisneri of publishing microscopical observations of the Kermes around 1715, observations made more than twenty years previously. This work begun investigation into the life process of the insect. Cestoni’s History of the Seed Kermes was inserted into Vallisneri’s pamphlet on the Chameleon in 1715 and reinforced the

332 Fontenelle 1706, 11.

333 Nissole 1717, 436.

334 Marsigli 1711.

335 Marsigli 1733[1711], 37.

thesis of the insect nature of the Kermes.³³⁶ The collaboration between Vallisneri and Cestoni, dating back to 1697, led them, already in that year, to describe the

metamorphic cycle of the flea.³³⁷ Following Cestoni’s observation of the 1680s, they showed that lice, cochineal and Kermes belonged to a similar class of organisms

because of their similar method of reproduction. This was acknowledged in 1714 by the naturalist from Neuchâtel, Louis Bourguet, himself a close collaborator of Vallisneri:

“It is also Mr Vallisneri and Cestoni who had found that the small animals producing the seed Kermes, the cochineal, the bedbugs and the lice of plants, and other insects they justifiably count as zoophytes, producing all of them without exception their fetus”.³³⁸

Touching on conceptions akin to the elucidation of the origins and transmission of species, having already been discussed in the Académie des Sciences, the question of ambiguity could not leave the French academicians cold. Claude-Joseph Geoffroy published, in 1717, a series of experiments of 1714 on cochineal and Kermes in the Mémoires de l’Académie des Sciences. A typical inquiry of that time studied organisms both through chemical analysis and microscopical observations, as was the method of Marsigli.³³⁹ Geoffroy examined Kermes and various sorts of cochineal, that from Poland, and that of the cactus Opuntia.³⁴⁰ In accordance with the programme of utility of the Academy,³⁴¹ Geoffroy wanted to try several animal substances in order to find the best dye. But one of his explicit goals was also “to prove that cochineal [was] an insect”³⁴² using both methodologies, chemical and microscopical. Geoffroy put the

Touching on conceptions akin to the elucidation of the origins and transmission of species, having already been discussed in the Académie des Sciences, the question of ambiguity could not leave the French academicians cold. Claude-Joseph Geoffroy published, in 1717, a series of experiments of 1714 on cochineal and Kermes in the Mémoires de l’Académie des Sciences. A typical inquiry of that time studied organisms both through chemical analysis and microscopical observations, as was the method of Marsigli.³³⁹ Geoffroy examined Kermes and various sorts of cochineal, that from Poland, and that of the cactus Opuntia.³⁴⁰ In accordance with the programme of utility of the Academy,³⁴¹ Geoffroy wanted to try several animal substances in order to find the best dye. But one of his explicit goals was also “to prove that cochineal [was] an insect”³⁴² using both methodologies, chemical and microscopical. Geoffroy put the