On tape and cystic worms : with an introduction on the origin of intestinal worms / by Carl Theodor von Siebold ; translated by T.H. Huxley.

  • Siebold, C. Th. E. von (Carl Th. Ernst), 1804-1885.
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: On tape and cystic worms : with an introduction on the origin of intestinal worms / by Carl Theodor von Siebold ; translated by T.H. Huxley. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    certain degree of development elsewhere. This is particularly the case with such intestinal worms as remain parasitic in the last stage of their existence^ viz.—that of sexual maturity, whilst the Gordiaccei [Gordius and Mermis), as soon as they are full- grown, quit their parasitical life, in order to become sexually mature, away from the animal they have infested. During these early wanderings, the worms in question commonly undergo a change of form—^a sort of metamorphosis, often accompanied by other phenomena of so highly remarkable and abnormal a character, that naturalists could not at first understand the varied character and import of these phases of existence, nor comprehend their relation with hitherto known facts.^ For a long time it was supposed that these discoveries were isolated facts, and they were regarded as a sort of curiosity; but here again the saying was verified, that that which at first appeared to be the exception, eventually proves to be the rule. By degrees, a mass of obser- vations upon certain remarkable metamorphoses of the intestinal worms accumulated, and constituted a complete chaos of seem- ingly irregular phenomena, which broke down every barrier hitherto set by the acknowledged laws of animal existence and propagation, until the penetration of the Danish naturalist, Steenstrup,^ succeeded in evolving a certain order out of this confusion, by the discovery therein of a hidden, underlying law of nature, by which all the phenomena that had seemed so devoid of plan could be reduced to order. Steenstrup named the newly discovered law, the Alternation of Generations,'' a phrase which describes this phenomenon. That an animal bears young which ' I may refer to the king's-yellow worms discovered by Bojanus in water-snails, and now become famous. (See Oken's ' Isis,' 1818, p. 729, plate 9, figs, a, t.) Of this discovery Oken says Observations of this kind make one dizzy. No less attention was excited by Von Bar's description of the Bucephaluspolymorphus of the fresh-water mussel. (See ' Verhandlungen der Kaiserl. Akad. d. Naturforscher,' B. xiii, 1826, p. 570, pi. 30); and by the Leucochloridum paradoxum, &r&t discovered by Ahrens, and afterwards described anew by Carus. (See ' Magazin der Naturforschenden Frennde zu Berlin, 1810, p. 292, pi. 10, figs. 12—19, and the < Verhandlungen der Kaiserlicheu Akademie,' Bd. xvii, 1855, p. 87, pi. 7.) s See his important essay on the ' Alternation of Generations,' Copenhagen, 1842, [This essay has been translated by Mr. Busk, and forms one of the publications of the Kay Society. It must not be forgotten that the first conception of the doctrine of the Alternation of Generations, and the first use of the term, are due to Chamisso. See his 'De Animalibus quibusdam e classc vermium Linnaana,' 1819, and ' Reise urn die Erde.'—Ed.]