ON THE GUSTATORY ORGANS OF THE RABBIt's TONGUE. 297 



tions, a flat anterior and an elevated oval posterior part. The flat and 

 front half of the tongue is of a redder colour than the more elevated 

 posterior, and upon a closer examination of its surface a pile, like 

 the pile of velvet, will be manifest, having scattered about it a few 

 isolated and rounder bodies ; these are distinguished by anatomists 

 into, 1st, the //e/orm papillae, which are found covering the greater 

 part of the dorsal surface of the tongue, while the more sparsely dis- 

 tributed round bodies are the fungiform papillae. It is not with 

 these papilla that we have to deal this evening ; but in lingual 

 anatomy there is a third class of papilla with which the sense of taste 

 is more intimately concerned ; these are the circumvallate papillae. 

 These in the human subject are arranged in a V shape across the 

 back part of the tongue, but in the rabbit they are found occupying 

 two patches, one on each side of the posterior part of the 

 tongue, at the junction of the oval elevation with the root, in the 

 position indicated by the black line in my diagram. They may be 

 easily overlooked by a careless observer, but as I should like many of 

 my hearers to work out this subject, I would advise them to procure 

 a tongue of a hare or a rabbit as fresh as can be got — if from a 

 recently killed animal the better — and wiping the mucus from its 

 surface, they will perceive at the part indicated an oval depressed 

 patch of a different colour to the surrounding tissues, and marked 

 with about ten to fifteen stride which cross its surface. If 

 these patches are cut out of the tongue, and placed in any of the 

 usual hardening agents, or, what is better, are frozen and cut into 

 sections at right angles to the course of these lamina, such a section 

 will be represented by Fig. 1, Plate XXII. 



By. referring to that we shall notice a row of compound papfll^e 

 derived from off-shoots of the connective tissue, and we shall see 

 that these lamin£e or stri^ which we saw in the oval patch were the 

 tops of these compound papilla which we now see in section — that 

 they are ridges of papillae, some of which are forked at intervals, 

 giving rise to secondary papillae, having furrows between them, but 

 the furrows so filled in by epithelium that no evidence of the sub- 

 jacent inequality exists. The epithelial layer is considerably thicker 

 on the summit of the papilla, and on that portion of it which is not 

 in approximation to its neighbour ; but on the sides where it is 

 more protected by the adjacent papillee the epithelial layer is thinner, 

 and it is in this situation that these gustatory cells are found. 



In the sectional view presented by Fig. 1 only three or fouf 



