112 SPECIAL HISTOLOGY. 



less membrane, which, however, does not admit of being 

 actually isolated. 



The bursa mucosa subcutanea are nothing but larger, simple, 

 or partially subdivided reticular spaces, in the subcutaneous 

 cellular tissue, in the fascia superficialis (bursa olecranii), or 

 between the laminae of the fascia muscularis (bursa patella). 

 The internal walls, smooth but uneven, are formed of common 

 connective tissue, possess no epithelium, and include a some- 

 what viscid, clear fluid. 



The elastic tissue exists abundantly in almost all parts of the 

 cutis ; but, in general, far more sparingly than the connective 

 tissue. More rarely it occurs in the form of true elastic mem- 

 branes, which may even resemble the densest elastic networks 

 of the arteries, as in the fascia superficialis of the abdomen and 

 thigh ; while more commonly it represents a loose reticulation of 

 coarser or finer fibres, as in the corium. The papilla (but not 

 all), and the panniculus adiposus, in which they are sometimes 

 wholly wanting, contain only fine elastic (nucleus) fibres. 



Smooth muscles, according to my observations, occur far 

 more extensively in the skin than has hitherto been supposed, 

 and particularly in the subcutaneous cellular tissue of the scrotum, 

 or the tunica dartos, which has thence received the name of 

 <c muscular membrane" (Fleischhaut), and of the penis, including 

 the prepuce and the anterior part of its body, where they run in 

 the form of yellow bundles (whose elements are figured in § 26), 

 measuring \" to \" partly contiguous to the vessels and nerves, 

 partly more isolated in the connective tissue ; they are some- 

 times converted into a network, but are more usually disposed 

 parallel to the raphe of the scrotum and the longitudinal axis 

 of the penis, though, more particularly in the latter situation, 

 they not unfrequently form large transverse bundles. 



2. In the areola of the nipple, the smooth muscles, which are 

 especially well developed in the female, are disposed circularly 

 in a delicate layer, which becomes thicker internally towards the 

 base of the nipple, and are, for the most part, visible to the 

 naked eye, on account of their yellowish red colour, and the 

 thickness of their bundles (up to \") ; in the nipple itself they 

 run in part circularly, in part perpendicularly, and are united 

 into a close network, through whose meshes the excretory ducts 

 of the lacteal glands pass. 



