Copy 1, Volume 1

The study of medicine. Improved from the author's manuscripts, and by reference to the latest advances in physiology, pathology, and practice / [John Mason Good].

  • Good, John Mason, 1764-1827
Date:
1834
Catalogue details

Licence: Public Domain Mark

Credit: The study of medicine. Improved from the author's manuscripts, and by reference to the latest advances in physiology, pathology, and practice / [John Mason Good]. Source: Wellcome Collection.

    56/784 (page 2)
    In some animals imperfor- ate, PHYSIOLOGICAL PROEM. Cuvier remarks,|one of the most invariable characters of an animal. A single mouth, he says, which some naturalists have fixed upon as a criterion, and contrasted with the multiplicity of the pores of the roots of vegetables, is less constant; for some animals of the family of medusa have several mouths, yet only one common stomachic cavity. ! ; The superior relative importance of the digestive organs in the animal economy is further illustrated by the fact, that the existence of parts of them may be traced in the early stages of the foetus, long before any rudiment of the spinal marrow, brain, or heart, can be detected. In this instance we also find the principle confirmed, that parts, first formed, are most rarely wanting. Thus, monsters have been met with, which consisted of nothing more than an abdomen, more or less perfect; but, the separate developement of a head, or chest, has never been observed. Man may be so incompletely developed, as to approach the point constituting the full organisation of certain lower animals, and to appear only as a mere digestive cavity. But, simple as his organisation may be, the zoophyte, which exhibits a like simplicity, can live and reproduce itself, such organisation being natural to it; but man must perish ; for his existence, as a mere unfinished sketch of himself, would be a contravention of the laws of nature. * ] whole range of the intestinal canal; and hence, its different parts are of very different diameters. In the mouth, where it commences, and in the pharynx, it is comparatively wide; it contracts in the cesophagus ; then again widens to form the stomach, and afterwards contracts again into the tube of the intestines. The intestinal tube itself is also of various diameters, in different parts of its extent ; and it is chiefly on this diversity of magnitude that anatomists have established its divisions. Its general length is five or six times that of the man himself; and, in children not less than ten or twelve times; [digestion in them being particularly active, from the greater supplies of nutriment required for growth and reparation. Meckel found the length of the small intestines very irregular in different persons, and that it varied from thirteen to twenty-seven feet, without any proportional difference in the stature of the body. In some animals, the intestinal canal is imperforate, the dross of the food being rejected by the mouth. This was once supposed to be the case in the medicinal leech: but Cuvier, Blumenbach, and Carus all agree, in opposition to Dumeril, that the leech has a minute anus, from which, however, only a little fecal matter is dis- charged, most of it being voided by the month. No anus has yet been satisfactorily detected in the tape-worm.+ In the actinize, one aperture combines the two offices of mouth and anus. t ] In the human subject, the anus is sometimes imperforate at birth, with a preternatural outlet, formed in some neighbouring part or organ to supply its place, in which case the feces have been discharged by the uretha, the vagina, the navel, or the groin. An extraordinary instance of such accommodation is that of a girl, * Andral, Anat. Pathol., t.ii. p.131. The stomach is formed subsequently to the intestines, and more frequently wanting. ¢ Carus’s Comp, Anat., vol. ii. p. 15. ¥ Ibid. p. 3.