MUSCLES. 



67 



the general surface. They consist of a duct, terminating in a blind, 

 pouch-like extremity, lined by an epithelium, in the particles of which 

 are included granules of sebaceous matter. The secretion is sub- 

 servient for the lubrication of the hair and the skin. There are gene- 



rally found in their ducts, parasites, of which two specimens are given 

 in b and c, fig. 53, These animals are found in almost every indi- 

 vidual, especially in those possessing a torpid skin; and they multiply 

 in sickness. 



The ceruminous glands of the ear resemble the sebaceous glands. 



SECTION III. 



MUSCLES. 



Muscles are formed of that substance usually called flesh, which 

 has a peculiar contractile power, producing motion ; they consist, 

 independently of the cellular tissue, vessels, and nerves, which 

 enter into their formation, of a special tissue, resembling the middle 

 coat of the arteries. Every muscle is composed of a number of 

 bundles of fibres, each of which consists of filaments ; each fila- 

 ment is divisible into fasciculi, and each fasciculus consists of a num- 

 ber of primitive particles or sarcous elements^ held together by a 

 tough, delicate, and elastic membrane called sarcolemma. The fibres 

 of the voluntary muscl(^, as well as the fibres of the heart and some 



