210 



SPECIAL HISTOLOGY. 



cells, without fat or pigment-granules. In their cavity, which is, hoAv- 

 ever, not always distinct, they sometimes contain a clear fluid, some- 

 times a small quantity of finely-granulated substance. 



Fig. 83. 



- / 



^.. ..^ 





-^ 

 ...^' 



§ 72. The Cerumen of the ear is commonly considered to be the 

 secretion of these glands, though this is only partially correct. If we 

 examine the yellow or broAvnish, soft or more solid, viscid substance 

 which is formed within the cartilaginous meatus, it is found to contain 

 various constituents : independently of a few hairs, occasionally an 

 Acarus foUiculorum, and epidermic cells in various numbers, there 

 occur, — 1. Very many cells completely filled with pale fatty matter of 

 0'009-0*02 of a line, usually of an oval, flattened, irregular shape ; in 

 •which, on the addition of water, or still better of caustic soda, the fat 

 is separated in isolated, round, or irregular dark drops. 2. Much free 

 fatty matter in the form of pale, small yellowish round drops, which, on the 

 addition of water, appear as dark spherical granules, from an immeasurable 

 minuteness up to 0'002 of a line and more; audit is only upon this addition 

 that they become quite distinct, but at the same time are decolorized. 



Fig. 83. — Perpendicular section through the skin of the external auditory meatus; 

 a, corium ; h, siralum Malpighii ; c, horny layer of the epidermis; d, coil of the ceruminons 

 glands; e, their excretory ducts ; /, their apertures; g, hair-sacs ; A, sebaceous glands of the 

 meatus; i, masses of fat. — Magnified 20 diameters. 



