924 THE SENSORY APPARATUSES. 



extremity rests on the mucous derma, where they receive the terminal nerve- 

 tubes ; and their external extremity reaches the epithelial layer, where they are 

 seen either between two cells, or in an orifice pierced in a single pavement cell. 

 Each taste-body is composed of a small cluster of cells, which are distinguished 

 from each other by their character and position ; those occupying the axis of 

 the organule are the gustative cells ; they are in communication with the nerve- 

 tubes on one side, and on the other are furnished, for the most part, with rods 

 which attain the free surface of the tongue. The superficial, or protective cells, 

 completely envelop the preceding ; they are a kind of epithelial-cells, imbricated 

 hke the skins of an onion. 



These sensitive organs are very numerous in the walls of the circumvallate 

 papillae, Schwalbe reckoned their number at 35,000 in the papillas of the Ox. 

 (As many as 1760 have been counted on one circumvallate papilla of the Ox. In 

 the papillm foliatcB of the Rabbit there are from 14,000 to 15,000 taste-bulbs ; in the 

 papillae of the Sheep and Pig about 9500). They are not met with in these papillae 

 only ; Lowen has found them in a large number of fungiform papillae, if not in 

 all. There is nothing extraordinaiy in this, as the whole surface of the tongue 

 may, in various degrees, appreciate savours. (Szabadfoldy has described small 

 oval or pyriform bodies, lying with their long diameter parallel to the surface. 

 The axis-cylinders of the gustatory nerves enter these, and terminate at their 

 lower part in a slight swelling ; so that they resemble small Paccinian bodies.) 



Differential Characters in the Apparatus of Taste in the other Animals. 



In the domestic Manimifera, the differences in this apparatus are found in the number and 

 variety of forms of the papillae of the tongue. 



In Ruminants, the circumvallate papillae are disposed in two rows at the base of the 

 tongue ; they are smaller than in the Horse, but more numerous— about a dozen being counted 

 in each row. In the Ox, the filiform papillae are covered by a homy sheath, which renders 

 them hard to the touch. 



In the Camel, there are only seen five or six circumvallate papillae, surrounded by papillsb 

 foliatae. 



The Pig, like Solipede, has only two circumvallate papillae. 



In the Dog and Cat, there are two principal papillae, and in their vicinity some smaller 

 calyces. The filiform papillae are composite, and covered by a thick homy layer. Between 

 them, regularly placed, are seen the fungiform papillae, which have a brilliant aspect when 

 looked at obliquely on the surface of the tongue. 



In the Rabbit, the gustatory nerve-endings are buried in special papillary organs, situated 

 on the limits of the upper surface and sides of the tongue, near its base, and named the foliated 

 organs. 



Comparison of the Apparatus of Taste in Man with that of Animals. 



This has been already alluded to at p. 432. 



CHAPTER III. 

 APPARATUS OF SMELL. 



Preparation. — See directions for the preparation of tiie nasal cavities. 



The sense of smell gives the appreciation of odorous emanations to animals. 

 The active instruments of this sense are the filaments of the first pair of cranial 

 nerves, which ramify in the upper part of the pituitary membrane ; this becomes. 



