138 



THE ESSENTIALS OF HISTOLOGY. 



muscular layer. The passage through the epidermis has no proper 

 wall, but is merely a channel excavated between the epithelium-cells. 



The ceruminous glands of the ear are modified sweat-glands. 



The sweat-glands are developed, like the hairs, from downgrowths of 

 the Malpighian layer of the epidermis into the corium, the rudiments 



FIG. 162. SECTION OF A SWEAT-GLAND IN THE SKIN OF MAX. 



a, a, secreting tube in section ; 6, a coil seen from above ; c, c, efferent tube ; d, intertubular 

 connective tissue with blood-vessels. 1, basement membrane ; 2. muscular fibres cut 

 across ; 3, secreting epithelium of tubule. 



which are thus formed becoming eventually coiled up at their extremi- 

 ties and converted into hollow tubes. The (muscular) fibres of the 

 tubes as well as the secreting epithelium-cells are thus epiblastic 

 structures. 



The sweat-glands receive nerve-fibres, and each gland has a special 

 cluster of capillary blood-vessels. 



