Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett.

  • Karl Theodor Ernst von Siebold
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    §13. If the vesicular cavities containing the liquid and colorless food of the Stomatoda be examined under the microscope by a horizontal central inci- sion, their contents appear colorless; but by changing the focus, viewing alternately the convex and concave surfaces of the vesicle, the points of junction between the colorless globules and the parenchyma appear colored pale-red. This appearance, due to an optical illusion, might easily deceive one into the opinion that the vesicles which are really colorless are colored. From this it is probable that Ehrenberg has described Bur Sana vernalis and Trachelius meleagris as having a red gastric juice.(1) The violet points which are found upon the back and neck of Nassula elegans and Chilodon ornatus are only collections of pigment granules, which, in the first case, are often absent, and in the second are often par- tially dissolved. This last violet liquid has been regarded by Ehre?iberg&) as a gastric juice resembling bile. § 14. The -solid particles of food, whether surrounded by the parenchyma or enclosed in a liquid vesicle, are moved hither and thither in the gelatinous tissue of the body, during the contracting and expanding movements of the animal. In some, the parenchyma with itg contained food moves in a reg- ularly circular manner, like the liquid contained in the articulated tubes of Chara.(1) In Loxodes bursaria (2) this circulation is remarkable, and of much physiological interest. Its cause is yet quite unknown, for in no case is it due to cilia, and it may be observed in individuals entirely at rest. Ehren- berg, (3> therefore, is incorrect in regarding it as due solely to a contratile power of the parenchyma, displacing the molecules. Much less is his ex- planation (4) satisfactory, since the digestive tube of an infusorium can be exteuded at the expense of its stomachal pouches, so as to fill the whole body, giving it the appearance of having a circulation of molecules through- out its entire extent. 1 “ Die Infusionsthierchen,” pp. 321, 326, 329. Ehrenberg has, moreover, in Trachelius melea- gris, confounded the contractile cavities with those non-contractile, and which receive the food. 2 Abhandl. d. Berliner Akad. 1833, p. 179 ; also u Die Infusionsthierchen,” pp. 319, 338, 339.* 1 Vaginicola and Vorticella. See Focke, Isis, Diatomacece, portions of Algae or Desmidieae, and with fragments of variously colored cotton, woolen, and linen fibres, will give a picture of the animal ; to complete which, it is only necessary to add a few loose strings to the bag to represent the varia- ble radiant processes which it possesses around the mouth.” This animal, which is often found with bits of cotton protruding from its mouth, assumes the most bizarre shapes. They appear to multi- ply by fissuration and gemmation even when filled with these heterogeneous particles, and, on the whole, present characteristics as remarkable as 1836, p. 7S6 •, also Meyen, Muller's Arch. 1839, p. 75. 2 Focke loc. cit.j also Erdl, Muller's Arch. 1841, p. 278. 3 Loc. cit. p. 262. 4 Muller's Archiv. 1839, p. 81. those of any animalcule with which we are ac quainted. — Ed. * [§ 13, note 2.] In this connection should be noticed the experiments of Will (Muller's Arch. 1848, p. 509). lie found evidences of a biliary ap- paratus, with Vorticella, Epistylis, and Bursaria. These evidences are based on chemical reaction, and he describes no anatomical apparatus. I men- tion this fact here, although Vor.ticella belongs truly to the Bryozoa, and Bursaria to the Plana- cia. — Ed.