238 TWENTY-THIRD LECTURE. 



(of irregular form, it is true) ; below, there is a filamentous 

 process. It is conjectured that the latter passes over as an 

 axis cylinder or primitive fibrilla (?) into the gustatory nerve 

 fibres, which run beneath the gustatory bud, and, there- 

 fore, that the gustatory cells may be terminal nerve structures. 

 No one has yet seen this, however. We shall first appreciate 

 the consequences subsequently, at the olfactory, auditory, and 

 optic nerves. The circumstance is interesting that so-called 

 mucous glandules (p. 141) occur in both varieties of papillse 

 (von Exner). 



Accurate facts are wanting concerning the nerve termina- 

 tions in the other papillae of the tongue. 



The human olfactory apparatus consists of a relatively 

 small part, which contains the termination of the specific nerve 

 of sense. This is the soft parts over the upper portion of the 

 septum, the upper and a portion of the middle turbinated 

 bone. The mucous membrane, which is here yellowish or 

 brownish, bears the appropriate name of the regio olfactoria. 

 All the remainder, the lower divisions of both main cavities, 

 as well as the three adjacent cavities, are unimportant acces- 

 sory parts, as has also been long since taught by compara- 

 tive anatomy. 



The latter division is lined by a very vascular mucous 

 membrane having ciliated cells (the Schneiderian membrane). 

 It contains an immense wealth of serous racemose glands 

 (p. 142). The mucous membrane is thinner in the accessory 

 cavities, and the glands begin to disappear. 



We have no intimate knowledge of the terminations of the 

 sensory nerves of the latter parts. 



Let us now return to the most essential parts, and exam- 

 ine more closely the structure of the regio olfactoria (Fig. 

 194). 



The region bordering on the Schneiderian mucous mem- 

 brane, which therefore is unprovided with olfactory fibres, 

 presents the old ciliated covering and the old serous glands. 

 Here, however, it is different. Bowman's gland tubes appear 

 in the mucous membrane, with yellowish cells. A thickened 



