The development of the gustatory organs in man : (a brief summary) / by F. Tuckerman.

  • Tuckerman, Frederick, 1857-
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: The development of the gustatory organs in man : (a brief summary) / by F. Tuckerman. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    PSYCHOLOGICAL LITERATURE. 3 largely imbedded in the stroma of the mucosa. Medullated nerves were fairly Shown in these papilla}. Directly beneath the basal cells of the epkheliutn was a fine, delicate, reticulated network, from which non- medullated nerve-fibrils passed upwards, penetrating the bulbs and neighboring epithelium. On the tongue of a six months' foetus the trenches of the papilla? were for the most part differentiated, and a few immature bulbs were detected on their lateral area. In the lateral organs of taste the furrows were quite free from epithelium, save at their lower part, and bulbs were scattered over the upper surface and sides of the folds. In a foetus at the seventh month, the bulbs had increased greatly on the lateral area of the gustatory papillae, and there was no apparent decrease in the number of those on the free surface. In a child about a month old the bulbs were quite uniformly disposed at the sides of the papillae, those of the lower tiers being less regular in arrangement and smaller, and lying partly in the mucosa. In a child four months old, isolated bulbs still occurred on the free upper surface of the papilla? of both gustatory areas. In the circumvallate papilla? of the adult, the bulbs did not appear to have decreased in number, but they had disappeared almost completely from the upper surface. In the adult papillae foliatae they were far less numerous than in early life, but were still normally present on the upper area of the folds. What purpose the temporary taste-bulbs (for such they appear to be) of the free upper surface of the circumvallate papillae subserve in the embryo, is difficult to comprehend. With the appearance of the bulbs of the lateral area, they gradually disappear, and, from all indications, perish. By the time the bulbs of the free surface of the papillae have attained their full development, bulbs in early stages of formation make their appearance on the wall, the lowermost bulbs being the most elementary. Were it otherwise, it might be conceivable, as Hermann suggests, that by an unfolding of the papillae laterally, the bulbs of the free area are shifted to the sides. In the present state of our knowl- edge, there seems to be no better way than to believe, with Hoffmann, that the bulbs of the free surface perish through the proliferation of the ordinary epithelium. It is not improbable that, after the bulbs have once disappeared from the upper surface, certain altered condi- tions of the epithelium prevent, save in rare instances, their recurrence there. Before concluding thi3 brief summary, the earlier investigations of Honigschmied, Hoffmann and Lustig should be mentioned. Honig- 3chmied, in a communication on the microscopic anatomy of the taste- organs (Ze.it. f. wiss. Zool., xxiii, 1873), merely remarks that he failed to detect in the circumvallate papillae of the new-born child any regular arrangement of the bulbs. Hoffmann (Virchow's Archiv, lxii, 1875) investigated the human embryo and new-born child for the purpose of studying the distribution of the taste-organs in man. In a fungiform papilla of a four and one half months' foetus, and also in the papilla? of one at the sixth month, he found taste-bulbs, but he failed to detect them in earlier embryos. He concludes that they are more frequent in embryos and in newly-born than in older individuals; that in embryos and new-born children they occur more frequently and in greater number on the free surface of the papilla? than in the adult, and that in old persons they are but rarely met with in this region. Lustig (Sitsb. d. k. AkoA. a. Wis*. Wien, Ixxxix, iii, 1884) failed to detect bulbs in the papilla? of a fretus at the end of the fifth month, but in one at the seventh he found them on the free upper surface of both circumval- late and foliate papilla?. While taste-bulbs were wanting in the tongue of a ten weeks* embryo, it is not improbable that they may yet be found in the incipient 3tages of growth in one of the twelfth week of intra- uterine life. F. Tuckerman.