DIGESTION.] 



PHYSIOLOGY. 



107 



moisture in, how is it that the skin is nevertheless 

 sometimes quito moist, as v^hen we perspire ? 



If you I'^ok at Fig. 15, you will see that the epi- 

 dermis is a one point pierced by a canal (h) running 

 right through it. You will notice that this canal is not 

 closed at the bottom of ihe epidermis, but runs right 

 into the dermis or true skin, where the canal becomes 



Fig. 16. — Coiled end of a Sweat Gland, Epithelium not sJunun. 



. ^e coil ; b, the duct ; c, network of capillaries, inside which the duct 



gland lies. 



M tube, with just one layer (e) of cells, like the cells 

 of the epidermis, for its walls. There is no room in 

 x^ig. 15 to show what becomes of this tube, but it 

 runs some way down under the skin all among the 

 blood-vessels, and then twisting itself up into a knot, 

 ,ends blindly, as is shown in Fig. i^, where b is 



HP 



