Till-: NASAL CAVITIES. 



11.- 



Pig. 235. 



and is insinuated, by the middle meat us. into the cells of the inferior or 

 anterior compartment of these osteo-cartilaginoits columns. It also penetrates, 

 by the semicircular opening of this meatus, into the sinus, to give it its 

 mucous covering, and is likewise prolonged into the apparatus of Jacobson. 

 Behind, it is confounded with the lining membrane of the pharyngeal cavity. 

 Its deeji face is separated by the periosteum or perichondrium, from the 

 bony or cartilaginous walls on which it is spread; and it is united to the 

 two prccited layers, this union being closest where it is thinnest, although 

 it can always be easily distinguished from these two fibrous layers through 

 out the whole extent of the nasal fossa. The free, or superficial face, presents 

 numerous glandular orifices, and is constantly covered by an abundance of 

 mucus, that prevents the desiccation to which this surface is exposed by 

 the incessant movement of air over it. 



STKCCTURE. The organisation of the pituitary membrane resembles 

 that of other mucous membranes, but it also presents some differences 

 rding as to whether it is examined near the nostrils or deeper in 

 the cavities. It is also usual to divide it into two portions : the olfactory 

 i,iiii-<>iix mi-mbrant; which covers the upper part of the ethmoidal turbinated 

 bone and cells ; and the Schnciderian membrane covering the inferior two- 

 thirds ot the nasal cavities. 



The corium of the Schtieiderian membrane is thick, soft, spongy, and 

 rose-coloured, and contains a large number of vessels and glands. The 

 latter are mucous or racemose glands, and arc extremely abundant in the 

 layer covering the septum of the nose, as well as at the inner face of the 

 cartilaginous appendices of the turbinated bones ; 

 though they are rare or altogether absent on the 

 external face of the latter. The epithelium is ciliated 

 and stratified, the deeper cells being round, those on 

 the sin-fact! columnar. 



The "/f'tn't'-ri/ linn-nits membrane differs from the 

 preceding by its greater thinness, its delicateness, its 

 slightly yellow tint, and the character of its epithe- 

 lium. The ,-nrmm contains straight or slightly-con- 

 i tiihnjiii- ii/iinds the glands of Bowman. The 

 if, it Li limn is olniunar and >7m////YJ, and readily 

 changes; in animals it is destitute of cilia. The 

 de< per cells oon tain aome yellowish pigment granules. 

 Schult/e dix-rilxs a> -//if. /-/;/ <<//>-, ceitain fusiform 

 nts which he considers as concerned in olfaction. 

 '! cells have two prolongations: a deep one, 

 which is connected with the fibres of the olfactory 

 nerve: and a superficial, that enters between the 

 epithelial oils and tends to approach the free surface 

 of the membrane. 



(The " olfactory cells " are thin, rod-like bodies 

 (Fig. 2'25, b), presenting varicose enlargements which 



connected with processes of deeper-seated nerve- CKLL80K T11 , 

 is. The epithelial cylinders proper (d, e) arc 

 related at their bases with the septa of connective 

 16 bel. nging to the sub epithelial glandular layer, 

 an 1 an- pr.-liahly in communication \vith tlieolt 

 cell. Sehidt/. <h M-ril>es another set of epithelial 

 cell, terminating externally by truncated flat surfaces, and to all 



MUCOUS Ml. MUIl A 



6, r, After 

 </,<. . 



Cl.rU. 



