THE ORGANS OF SENSE. 



237 



Fig. 192. — Vertical section through the so-called papilla 

 foliata of the rabbit. 



nerves of taste. Both systems of papillae occur in man, 

 though the foliatae are subject to many individual variations. 

 The change is great in mammalial animals. Cats have no 

 papillae foliatae ; Guinea-pigs have no circumvallatae. 



We have now to examine the above nerve terminations 

 more closely. They are more recent histological acquisitions 

 (Loven, Schwalbe, and others). Complicated cup or bud- 

 shaped organs, the so-called gustatory buds, have been met 

 w i t h here. Large 

 numbers of them oc- 

 cur, as is distinctly 

 represented in our 

 Fig. 192, in the lateral 

 walls of the papillae 

 themselves, and in the 

 inner surface of the surrounding 

 mounds of mucous membrane. 

 The gustatory bud (about 0.08 

 mm. high in man) is an epithelial 

 structure. It (Fig. 193) permeates 

 the entire thickness of this layer, 

 and its points lie free. 



We meet, in the first place, 

 with flattened, lancet-shaped, 

 pointed parietal cells (a). They 

 stand like the staves of a barrel. 

 Above, possibly running out into 

 the finest ciliae, they surround a 

 small opening. 



These supporting or cover cells 

 (2 a) ensheath an inner cell forma- 

 tion, belonging to the axis portion 

 of the gustatory bud, the rod cell, 

 or, as it has also (hypothetically, 

 it is true) been called, the gusta- 

 tory cell (2 b). 



Above, there is a sort of styliform or rod-shaped process 



ze 



Fig. 193. — 1. Gustatory bud of the 

 rabbit ; 2 a, cover cells ; 2 b, rod cells ; 

 2 c, a rod cell with a fine terminal fila- 

 ment. 



