SEBACEOUS FOLLICLES. 413 



the exhaling or absorbing pores, but their connexion with the 

 vessels which perform these functions has not yet been demon- 

 strated. ./ 



The internal surface of the skin, when carefully dissected 

 from the subjacent cellular membrane, in a subject of ordinary 

 corpulency, appears to have some adipose substance in its 

 texture ; but, as has been already mentioned, when the cellular 

 membrane is destroyed, these portions of adipose matter 

 disappear, and the surface of the skin appears pitted. It is 

 probable that this connexion of the cellular membrane and skin 

 may occasion that delicacy of skin which appears in some 

 hydropic patients. 



In some places on the under surface of the skin are small 

 glands called miliary, from their resemblance to the millet seed ; 

 these glands are supposed to secrete a sebaceous matter, but 

 they are not so general as has been supposed. 



They are sebaceous follicles or ducts, which open on the 

 external surface of the skin, and contain an oily substance, 

 which, sometimes, has the consistence of suet or tallow ; when- 

 these ducts are filled with sebaceous matter, their orifices are 

 often covered by a black substance, which accidentally adheres 

 to the surface of the matter, and forms very small black spots 

 in the skin. These often occur on the nose and ears, and may 

 be removed by pressing out the sebaceous substance, which 

 rises up in the form of small worms. Sometimes this secretion 

 accumulates in the ducts in such quantities, that it forms small 

 tumors in the skin. 



Fig. 107. Fig. 107, is a portion of skin cut vertically 

 from the nose of an old man, in order to show 

 the sebaceous follicles and their ducts, which are 

 magnified much beyond their natural size. They are found in 

 all parts of the body, with the exception of the palms of the 

 hands and soles of the feet ; but in many parts only become 

 visible to the naked eye, in diseased conditions of the skin. 

 They are most numerous in the face, behind the ears, and in 

 the arm-pits and groin. There is a strong analogy between 

 them and the follicles of mucous membranes. 

 35* 





