Volume 1

A student's text-book of zoology / by Adam Sedgwick.

  • Sedgwick, Adam, 1854-1913.
Date:
1898-1909
Catalogue details

Licence: In copyright

Credit: A student's text-book of zoology / by Adam Sedgwick. Source: Wellcome Collection.

    41/640 (page 25)
    Infusoria were discovered towards the end of tlie 17th century in a vessel of .stagnant water by A. von Leeuwenhoek, who made use of a magnifying glass for the examination of small organisms. The name Infusoria, wliich was at first used to denote all animalculae which a]ipear in infusions and are only visible with the aid of a microscope, was first brought into use by Ledermiiller and Wrisberg in the last century. Later on the Danish naturalist 0. Fr. Muller made valuable additions to our knowledge of Infusoria. He observed their conjugation and their reproduction by fission and gemmation, and wrote the first systematic work on the subject. 0. Fr. Muller included a much larger number of forms than we do nowadays, for he placed among the Infusoria all invertebrate water animal- culse without jointed organs of locomotion and of microscopical size. The knowledge of Infusoria received a new impulse from the comprehensive researches of Ehrenberg. The principal work of this investigator, “Die Infusionsthierchen als vollkommene Organismen,” discovered a kingdom of organisms hardly thought of. These were observed and portrayed under the highest microscopic powers. Many of Ehrenberg’s drawings may even yet be taken as patterns, and are hardly surpassed by later representations, but the significance of the facts observed has been essentially corrected by more recent investi- gations. Ehrenberg also conceded too great an extent to the group of Infusoria, including not only the lowest plants such as Diatomacecu, Desmidiacece, under the name of Polygastrica anentera, but also the much more highly organized Rotifera. As he chose the organization of the last-named for the basis of his explanations, he was led into numerous errors. Ehrenberg ascribed to the Infusoria mouth and anus, stomach and intestines, testis and ovary, kidneys, sense-organs, and a vascular system, without being able to give reliable proofs of the nature of these organs. There very soon came a reaction in the way of regarding the Infusorian structure; for the discoverer of the RMzopoda, Dujardin, as well as von Siebold and Kolliker (the latter taking into consideration the so-called nucleus and nucleolus), referred the Infusorian body to the simple cell. In the subsequent works of Stein, Claparede, Lachmann, and Balbiani numerous differentiations der Infusorien.” Jen. Zeitschrift, Tom. VII., 1873. 0. Biitsclili, Studicn iiber die ersten JEntwickelungsvorgdnge dcs Eizelle, die Zelltheilung und die Conjuga- tion des Infusorien, Frankfurt, 1876. Saville Kent, A Manual of the Infusoria, London, 1880-2. Maupas, “ Sur la multiplication des Infusoires Cilies.” Arch, 'd. Zool. Exp. (2), 6, and “La Rajeunissement Karyogamique cliez les Cilies, ibid. (2), 7.