574 THE SKIN. 



epithelia are not easily discernible. Treatment with alcohol and 

 turpentine brings the nucleated cuboidal epithelia distinctly to 

 view, and in such specimens we also recognize that the acinus 

 contains several layers of epithelia. In many sebaceous glands 

 a parasitic mite is found, the acarus or demodex folliculorum, 

 which is harmless, however. 



(10) The sudoriparous glands are composed of a single coiled 

 tubule, lying in the deep parts of the skin, usually near or in 

 the subcutaneous tissue j the same tubule produces not only the 

 coil, but the duct also, the difference being that the coiled portion 

 of the tubule is lined with cuboidal epithelia, and the duct, up 

 to the point where it reaches the rete mucosum, with the col- 

 umnar variety. If we assume a prolongation of the outer 

 epithelial layers into the depths of the derma, the formation of 

 the sweat-gland is easily understood. 



The sudoriparous glands are present all over the skin, varying 

 in size in different individuals and in different localities; they 

 are most numerous in the palms of the hands and the soles of 

 the feet ; the largest are found in the axillae and in the neighbor- 

 hood of the anus j they are not found in the glans penis and 

 the inner surface of the prepuce. They are all inserted in an 

 oblique direction in the derma, corresponding to the general 

 arrangement of the connective-tissue bundles. Their orifices on 

 the surface of the skin, in the furrows between the papillary 

 ledges, are perceptible to the naked eye. The sweat-glands at 

 the borders of the eyelids the so-called glands of Moll have, 

 it is maintained, spiral terminations, instead of coils, and empty 

 into the hair-pouch of the cilia. The ceruminal glands of the 

 external auditory canal are constructed like sudoriparous glands, 

 but secrete an unctious substance, which is commonly called 

 ear-wax. 



By cutting through the coil, transverse, oblique, and longi- 

 tudinal sections of the tubule are produced. The lining epithe- 

 lium is, in this situation, a cuboidal or short columnar epithelium 

 in one layer, attached to a delicate hyaline membrane. In the 

 empty condition of the gland the caliber is very narrow, and the 

 cement-ledge of the epithelia is plainly marked at the surface 

 bounding the caliber. (See Fig. 241.) 



The connective tissue carries a large number of capillaries, 

 and produces a capsule surrounding the coil, and prolongations 

 passing around the tubule through its whole extent. In the con- 

 nective tissue there are seen smooth muscle-fibers, which are very 



