THE NOSE. 419 



siderable for a mucous membrane, it is remarkably delicate 

 and soft, and is so much affected by almost all reagents as to 

 allow of its being studied only with considerable trouble. 

 According to my observations, it should be described as a 

 squamose cylinder -epithelium ; at all events, in opposition to 

 Todd and Bowman, I always find as its outermost layer, one 

 or two strata of slender, vertical cells, 0*005 — 0007'" long, 

 whilst it must be allowed that, more deeply, spherical elements, 

 of 0*003 — 0-004"', alone appear to exist. All these cells have 

 minute, round nuclei, usually pale, finely granular contents 

 of a brownish hue in the deepest layer only in the Rabbit and 

 Dog, and such delicate membranes, that in water they instantly 

 burst. Although the ciliated cells of the nasal fossae are much 

 more readily affected by water than those of other situations, 

 this is true to a much greater extent as regards the cells 

 of the olfactory region; and the destructive effect of the 

 filling of the nasal cavities with water (E. H. Weber) and 

 other fluids is thus easily accounted for, as well as, on the other 

 hand, is the ready transition of volatile substances through the 

 epithelium rendered intelligible. For the moistening and 

 protection of this epithelium throughout the region in which it 

 exists, it is furnished with a great number of the " glands of 

 Bowman," which is the more remarkable, because the imme- 

 diately contiguous, ciliated mucous membrane is but scantily 

 supplied with glands, or is wholly without them. These glands 

 are simple cylinders, either straight or slightly convoluted at 

 the lower end and 0-08 — 0*1'" in length, or elongated pyriform 

 follicles, situated principally between the larger branches of 

 the olfactory nerves, in crowded rows, in part, however, more 

 isolated, as at the lower boundaries of the olfactory region. 

 They most nearly approach certain forms of the Lieberkuhnian 

 glands, and the sudoriparous glands of the foetus. I have 

 never yet noticed divisions of the follicles, although it is very 

 possible that I may have overlooked them, since these organs 

 are extremely delicate, and easily altered. Their canals, 0014 — 

 0-025"' wide, are lined by a beautiful, simple epithelium, com- 

 posed of rounded polygonal cells, 0006 — 0-008'" in size, con- 

 taining more or fewer yellowish or brownish pigment-granules, 

 to which is due the varying colour of the olfactory mucous 

 membrane. Their excretory ducts are rather more contracted 



