72 



By teasing the fresh tissue the structural elements composing the 

 bulbs of this area were isolated without great difficulty. They do not 

 appear to differ very materially from those of the taste areas of the 

 calf, sheep, rabbit and man ^). 



The covering or peripheral cells are from 15 to 25 in number and 

 are arranged in more than one layer. They are elongated, slightly 

 flattened, nucleated cells, the two extremities of which taper gradually 

 to a point. 



The gustatory or central cells are smaller, fewer in number, and 

 more delicate than the preceding. They are spindle-shaped or staff- 

 shaped, and consist of a cell body or elliptical-shaped nucleated en- 

 largement, usually situated near the middle of the cell, and two pro- 

 cesses. The peripheral process, broader than the central and nearly 

 straight, is sometimes prolonged into a fine styliform extremity, which 

 usually projects a short distance beyond the orifice of the bulb. In 

 other cells the peripheral process terminates in a somewhat blunted 

 extremity. The central process, more slender than the peripheral and 

 occasionally slightly varicose, usually terminates in a fine point. In 

 none of the taste cells isolated by me did the central process show 

 a tendency to become branched. 



Non-medullated nerve-fibres enter the bases of the folds, and 

 their terminal branches can be seen ramifying directly beneath the 

 epitheUum containing the taste bulbs, with which, in some instances, 

 they appear to be continuous. Sertoli*) and Ranvier^) state that 

 they have traced nerve-fibrils directly into the taste bulbs in this re- 

 gion, the former in the horse, the latter in the rabbit. 



The Papillae circumvallatae. — The papilla circumvallata is ellip- 

 tical in form. The base is pedunculated, and the exposed surface 

 slightly convex or flat with abruptly rounded edges. The interior of 

 the papilla contains serous glands, and at its upper part are many 

 secondary papillae. Serous glands are plentiful about the base of the 

 papilla, and their ducte open into the trench at its sides and deeper 

 part. 



1) LovEN isolated and figured the peripheral and gustatory cells of 

 man and the calf (Arch. f. mikr. Anat., Bd. IV, 1868, S. 103, Taf. VII); 

 ScHWAXBE of the sheep and man (ibid., Bd. IV, 1868, S. 172, Taf. XIII); 

 Engelmann of the rabbit (1. c. S. 782, figs. 298, 299); y. Wrss of man 

 (I. c. S. 243, Taf. XV) ; and W. Keause of man (AUgem. u. mikrosk. 

 Anat., 1876, S. 187, Fig. 103.) 



2) Osservazioni sulle terminazioni dei nervi del gusto. Abstract in 

 Centralbl. f. d. med. Wiss., Nr. 55, 1874, S. 871. 



3) Traite techuiq^ue d'histologie. Paris, 1882, p. 949. 



