216 SrECIAL HISTOLOGY. 



B. OF THE CERUMINOUS GLANDS. 



§ 71. 



The cevuminous glands of the Ear are brownish simple 

 glands, in external appearance precisely similar to the sudori- 

 parous glands, which do not exist in the whole external 

 auditory meatus, but only in its cartilaginous portion, where 

 they are situated between the lining membrane of the passage 

 and the cartilage, or the fibrous substance which supplies its 

 place, in a tough subcutaneous tissue, containing little fat. 

 They form a connected yellowish-brown layer, visible enough 

 to the naked eye, which is thickest in the inner half of the 

 cartilaginous meatus, and becomes gradually thinner and more 

 lax externally, extending, however, quite as far as the carti- 

 laginous meatus itself. Each ceruminous gland consists of a 

 glandular coil and an excretory duct. The former (fig. 83 d), 

 JL'" — I — §'" in size, is formed by the multitudinous convolu- 

 tions of a single canal of 003'' — O06'", on the average 

 Q-04'" — 0*05'" thickness, which occasionally, although not 

 constantly, throws out little diverticula, and terminates in a 

 blind slightly enlarged end. From the coil a short straight 

 excretory duct, 0-017 — 0*024"' thick, passes perpendicularly 

 upwards, penetrates the corium and epidermis of the auditory 

 meatus, and usually opens independently in a circular pore of 

 0044"', or else into the upper part of a hair sac. 



The following is the intimate structure of the ceruminous 

 glands. The canals of the coil present a fibrous coat and an 

 epithelium, the former being 0004 — 0*005'" in thickness, the 

 latter 0004'". The fibrous covering presents exactly the same 

 conditions as in the larger sudoriparous glands, that is, it con- 

 sists of an internal longitudinal layer of smooth muscles, 

 0*0023 — 0*0026'" in diameter, and an external layer of con- 

 nective tissue, with scattered nuclei, and occasionally very fine 

 transverse nucleus fibres. The epithelium rests immediately 

 upon the muscular layer, and consists of polygonal cells of 

 0*006 — 0*01'" in a single layer, which contain a greater or 

 smaller number of yellowish-brown pigment granules, of 

 immeasurable minuteness, insoluble in acids and alkalies in the 



