Protistology 3 (4), 283296 (2004) Protistology A brief history of ciliate studies (late XVII the first third of the XX century) Sergei I. Fokin Biological Research Institute of St.Petersburg State University, Russia; * Dipartimento di Etologia, Ecologia ed Evoluzione, Univeritq di Pisa, Italy Summary The most prominent protistologists who worked with ciliates from the Leeuwenhoek time up to the beginning of the XX century are mentioned. Their achievements in ciliatology and especially in taxonomy of ciliates are briefly discussed on the basis of the original literature and reviews, published during the last 150 years. Key words: ciliates, history of ciliatology, protists Ciliates were among the first living microscopic some other Eastern European countries. The present organisms to be discovered and described by A. article attempts to fill this blank at least in part. Leeuwenhoek (Dobell, 1932) and have attracted much Early studies of the world of protists were triggered scientific interest ever since. Apart from a plethora of by the invention and progress of microscopes in the first studies devoted especially to representatives of this half of the XVII century. However, at first microscopes group, some ciliates are favourite model objects used interested only a few physicists, astronomers and in diverse investigations in the fields of cytology, philosophers (Sobol, 1949). “The invisible world of molecular biology, genetics, biochemistry and physio living creatures” waited for its researcher. More than logy. Despite of a number of publications dedicated to half a century since the invention of the microscope the history of protistiology (Calkins, 1901; Cole, 1926; had passed, before such a man appeared: a manufac Brodsky, 1937; Corliss, 1978, 1991,1997; Kuznicki, turer from Delft and a selftaught optician Antony van 1982; Entzeroth, 1994; Geus, 1994; Leadbeater and Leeuwenhoek (16321723) (Dobell, 1932; Corliss, McCready, 2000; Vickerman et al., 2000; Fokin, 2001a; 1975, 2002). Though he had no scientific education, it Wolf and Hausmann, 2001; Kuznicki, 2003), the major was Leeuwenhoek who made the first reliable obser historical stages of development of ciliatology are still vations of live ciliates. He described them, as well as not enough reflected in modern literature. Especially it many other microscopic objects, in his letters to the is true for the development of ciliatology in Russia and London Royal Society starting from 1674 (Dobell, 1932; Corliss, 1975). Leeuwenhoek was also the first to * Current address for communication and reprints draw a ciliate (apparently, Nyctotherus), from the frog’s © 2004 by Russia, Protistology 284 · Sergei I. Fokin gut (1683). Those observations, amazing for their time, Altogether, quite many XVIII century scientists were made with the use of very simple microscopes, in described and made sketches of ciliates and other tiny fact, magnifying glasses, which, however, allowed a animals, unicellular or multicellular (flagellates, remarkably high magnification (up to 300 times). amoebae, rotifers, trematode larvae), then considered Leeuwenhoek introduced a lot of technical innovations as “infusoria” (see Kutorga, 1839). S.S. Kutoga (1805 and was probably the first to achieve in his microscopes 1861), one of the first Russian scientists to study ciliates, the illumination effect resembling the presentday “dark wrote in 1839: “this discovery [of infusoria] excited all field”. the researchers, and everybody in possession of a Judging from his detailed descriptions, Leeuwen microscope hastened to enjoy the sight of perpetual hoek dealt with Carchesium, Chilodonella, Coleps, movement of this invisible world”. Among the resear Colpidium, Cyclidium, Dileptus, Kerona, Paramecium, chers fascinated by “infusoria” were Baker (1698 Vorticella and a number of other ciliates (Corliss, 1975). 1774), who described Lacrymaria in 1753, and He did not only mark morphological details of the Wrisberg, who first applied the term “infusoria” to “animalcules” observed but also measured them, protists (1765). In 1769 Ellis (17101776) experimen described their reproduction, retractivity and appa tally induced extrusion of trichocysts in Paramecium, rently some conjugation stages. and in 1796 Guanzati first described cysts in a ciliate, At the same time, however, the “invisible world” belonging presumably to the genus Amphileptus (Corliss, attracted several more researchers. For instance, in 1678 1991). Somewhat earlier (1754) Joblot described the Ch. Huygens (16291695) described several ciliates in contractile vacuole and noted the characteristic position a letter to his brother (Dobell, 1932). Buonanni (1638 of cilia in different ciliates. 1725) was the first to publish a drawing of a ciliate Scientific achievements of O.F. Mzller (1730 (apparently, Colpidium) in 1691 (Cole, 1926). Two year 1784), a famous Danish zoologist and the first later King sketched several protists, including Euplotes systematist of ciliates, deserve special mention (Corliss, (Corliss, 1991). 1986). His outstanding monographs “Vermivm The middle of the next, XVIII, century was terrestrium et fluviatilium seu animaliun infusoriorum, dominated by the ideas of Carl Linneaus (17071778), helminthicorum et testaceorum” (Mzller, 1773) and the father of modern taxonomy and biological nomen “Animalcula infusoria fluviatilia et marina” (Mzller, clature. Being a botanist, he had little concern for water 1786) contain about 300 species descriptions of “animalcula” and did not trust the microscope. Only the bacteria, protists (mostly marine and freshwater ciliates) 12th edition of his Systema Naturae (1767) included and small multicellular animals. Mzller described protists (four genera), two of which were personified as ciliates from marine sand, scuticociliatids, gymno Volvox and Vorticella. The rest of Protozoa were huddled stomatids, tintinninds, oligotrichs, suctoria, the into two other genera, whose names, Chaos and Furia, colonial Ophridinium, the marine loricate Folliculina, told their own tale. “Mysterious living molecules, to be and made notes on their ecology and physiology. In understood by our descendants”, that was how Linnaeus naming the animals discovered he adhered to the characterised ciliates (Sobol,1949). However, as early as binominal nomenclature rules, and many Latin names in 1703 an anonymous author published a drawing of, of ciliates are still followed by the letters O.F.M. Mzller unmistakably, a paramecium (Woodruff, 1945; Wichter should be credited with the correct interpretation of the man, 1953). The same ciliate was investigated by L. Joblot conjugation phenomenon in ciliates as a sexual process. (16451723), who produced in 1718 a pioneer descrip More than 100 years had to pass before protozoologists tion of ciliature, nuclei and contractile vacuoles in (Balbiani, 1861) finally accepted this notion. Note ciliates. In 1752 J. Hill (17171775), in his famous worthy, Mzller considered protists as the most simply “History of Animals”, gave the “slippershaped” ciliate organized living creatures, a view supported by the its present name, Paramecium. He is the author of many natural philosophers – Lamarck, Schweigger, Oken – other names, including Cyclidium and Enchelys. who relied on Mzller’s works. Unfortunately, Hill’s priority has not been retained, The first Russian protozoological research dates because his descriptions were made 6 years before the back to the late XVIII century. A zoologicalphysiolo January of 1758, since which time, according to the gical dissertation of M.M. Terekhovsky (17401796), International Codex of Zoological Nomenclature, “On Linnaeus’ Chaos infusorium” (1775), was generic names are accepted as valid. Also in 17441748, defended in the University of Strasbourg (Sobol, 1949). A. Trembley (17001784), renown for the study of the On the basis of longterm successive experiments with hydra, investigated division in “funnelshaped polyps” different infusions, the author proved in 88 paragraphs (ciliates from the genus Stentor) and described repro of his dissertation that ciliates “as all animals, originate duction in Epistylis, Carchesium and Zoothamnium by way of reproduction from antecedent parents”. Thus, (Kanaev, 1972; Corliss, 1991). as early as in 1775, Terekhovsky confuted the wide Protistology · 285 spread theory about spontaneous generation of ciliates, associated with a broader geographical range of studies giving an infallible proof of their animal nature. The and further improvement of microscopic techniques: main works of L. Spallanzani (17291799) on this topic the invention of the Chevalier complex object lens, the saw light in 1765 and 1776. These problems stirred the Lister microscope and the Ross correction eyelens (see scientific world even in the first half of the XIX century. Karpov, 2001). Secondly, after the “critical mass” of “Let those destined to study the nature deeper species descriptions had been accumulated and determine whether these water animalcula belong to comparative taxonomic studies began (Corliss, 1992), worms, or to insects, or to some other animal class”, – attempts at classification of protists on the basis of wrote Terekhovsky in the conclusion of his dissertation. characteristics of their groups became possible. – “Let them also, following Hill and Mzller, determine The next prominent researcher and systematist of more precisely their genera and species” (Sobol, 1949). ciliates after O.F. Mzller was, undoubtedly, Ch. G. This task was to be accomplished in the