100 THE MECHANICAL FUNCTIONS. 



The Epidermis consists of a thin expansion of 

 albuminous matter, arranged in layers, but appa- 

 rently homogeneous in its texture and composition. 

 On accurate examination of portions which have 

 been long macerated in water, they are found to con- 

 tain a great number of minute scales, the product of 

 the chromatogenous glands already described; and 

 which have been agglutinated together into a solid 

 layer by means of the albuminous matter secreted 

 by the blennogenous glands. The epidermis is 

 perforated at regular intervals by ducts* arising 

 from a third set of glands, situated in the most in- 

 terior portion of the corium, the office of which is 

 to secrete the perspiration, and which may accord- 

 ingly be termed the sudorific glands.-\ This fluid, 

 which, under ordinary circumstances, escapes in 

 the form of invisible vapour, but is, at other times, 

 deposited in a liquid state, is conveyed from these 

 glands by the above-mentioned ducts, which pur- 

 sue a spiral course through the whole thickness of 

 the corium, corpus mucosum, and epidermis, till 

 they open obliquely at the surface of the latter. J 



The extreme branches of the lymphatic absorb- 

 ents also extend into the substance of the epider- 

 mis, but nowhere penetrate to its external surface. 



of corpus mucosum adheres to the former, while the remaining por- 

 tion which surrounds the bases of the papillte remains attached to 

 tliem, constituting a reticulated layer perforated by the papillee. It 

 was this appearance which led Malpighi, the discoverer of this part 

 of the skin, to consider it as a real network, and to give it the name 

 of Rete Mucostim, by which it is still frequently known. 



* The ducts are termed by Breschet, Canaux sudoriferes, ou hi- 

 drophores. 



t These, together with the ducts, constitute the appareil diapno- 

 yene of Breschet. 



