28 THE EXTERNAL AND MIDDLE EAR, BY J. KESSEL. 



face and Lead, invests the cartilage, and at its inferior extremity 

 forms a simple duplication known as the lobulus. Its whole 

 surface is covered by lanuginous hairs, into the sacs of which 

 sebaceous glands, having a diameter of from 0'5 to 2'0 millimeters, 

 open. These last attain their greatest size in the interior of the 

 concha, where, in comparison to the size of the hairs, they are 

 very large and numerous, so that their openings are visible to 

 the naked eye as minute fossae. This relation is altered in 

 many individuals at the entrance of the external meatus, where 

 the woolly hairs are remarkably developed, on which account 

 they have been named " tragal " hairs. Small sweat glands, of 

 0*15 of a millimeter, are chiefly found upon that surface of the 

 auricle that is turned towards the skull. 



The subcutaneous tissue of the external skin of the auricle 

 does not everywhere present exactly the same features. It 

 contains numerous elastic fibres which may be traced passing 

 through the perichondrium as far as to the fibres of the reticu- 

 lar cartilage. On the concave surface of the auricle this tissue 

 forms a thin lamina firmly attached to the perichondrium, on 

 which account the skin is not here moveable. On the concave 

 surface the subcutaneous tissue is more abundant, and the skin 

 can consequently be moved hither and thither to some extent, 

 and in the lobule and lower parts it contains fat cells in its 

 meshes in gradually increasing proportion, by which means the 

 form and thickness of the lobule, whicji it is well known pos- 

 sesses no supporting cartilage, is essentially determined. 



The auricle derives its blood from various sources. The 

 capillary plexuses proceeding from the arterial trunks ramify 

 around the hair follicles and glands of the cutis and in the 

 cartilage. A few of the vessels, according to Pareidt (31), 

 traverse the cartilage obliquely from the inner to the outer side, 

 whilst others remain in the perichondrium. Some of the latter, 

 according to Meyer (28), give off minute branches that pene- 

 trate the cartilage, and ramify in its substance. 



Nerves are found most abundantly on the convex surface of 

 the concha. They are less numerous on the concave surface 

 and in the lobule. The larger trunks accompany the larger 

 vessels, and penetrate the mesial surface of the cartilage in 

 order to reach the skin of the lateral surface. 



