[28] K. Sprengel, Hist. de la Medicine.
QUARTERLY SUMMARY OF MEDICAL AND SURGICAL INTELLIGENCE.
I. ANATOMY.
1. Papillæ of the Tongue.—At the upper surface of the tongue, say MM. Leuret and Lassaigne, in their recent work on digestion, the mucous membrane presents projections of three different species; and these are, the sensitive papillæ, the epidermoid papillæ, and the mucous cryptæ. The sensitive papillæ are numerous. They occupy the anterior four-fifths of the tongue, on which they are implanted by a narrow pedicle. The rounded head of these papillæ is much more prominent in the living subject, than after death; but injections are capable of restoring them to their pristine form. Nervous fibres from the lingual branch of the fifth pair have been distinctly traced to their roots. These papillæ are of various sizes; at the root of the tongue they form a V. They are all vascular and nervous. The sense of taste is referred by these writers almost exclusively to the above papillæ.
The epidermoid papillæ are of a nature similar to those retroverted prominences so remarkable on the tongue of the cat; as well as in the lion, and some other animals. They are larger in many species than in man, and, in general, the sensibility of the tongue appears to diminish in proportion to the remoteness of the subject from the human structure. The epidermoid papillæ are separated from the tongue along with the epidermis, or rather, epithelium, by maceration for a few days in vinegar. They are pyramidal in form. They are grouped round the sensitive papillæ, except on the edges and point of the tongue, where they are rare. Their base is perforated, and always gives outlet to a crypta. In an epithelium separated from the tongue, these minute and numerous perforations are easily distinguished from the larger ones left by the sensitive papillæ.
The office of the epidermoid papillæ appears purely mechanical.
The only cryptæ which produce, of themselves, a visible projection on the surface of the tongue, are situated at its base. They are formed by the mucous membrane, like other cryptæ, and are scattered between the sensitive papillæ.
In the tongue of birds, there is always a bone or cartilage; and the external membrane is dense. In reptiles the tongue is soft, possessed of little sensibility, and capable of great elongation. In fishes it is endowed with little motion, and is often wanting.—Bulletin Medicale.