PERSPIRATION. 271 



" The pores, which Leuwenhoek imagined in it," are not 

 visible. 



" The importance of the cuticle to organised systems is de- 

 monstrated by its universality in the animal and vegetable king- 

 doms, and by its being distinctly observable in the embryo from 

 the third month at latest after conception." 



The purpose of the cuticle is, 1. To cover the cutis like oiled 

 silk, and preserve it moist and fit for its functions. Were the 

 cutis exposed to the atmosphere, it would dry, and its vessels 

 could neither excrete nor absorb, nor its nerves feel. This is 

 partly seen, in regard to mucous membranes, when the uterus 

 remains prolapsed beyond the opening of the vagina.s The pro- 

 truded membrane of the vagina then becomes pale and shrivelled, 

 like a dried bladder. The mucous membrane of the eyes and 

 nostrils, and of the mouth, would dry up, but for the additional 

 moisture supplied to the former by the lachrymal glands, and to 

 the latter by the salivary ; and so would the bronchial mucous 

 membrane, if the air did not become first charged with moisture in 

 passing through the mouth and nostrils, and if it passed through 

 the bronchiae instead of entering and returning. 2. To protect 

 the cutis, thus preserved moist, from the immediate contact of 

 substances; some of which would be too easily absorbed, and 

 others would produce painful sensation. 



" The inner part of the cuticle is lined by a fine mucous mem- 

 brane, denominated, from the opinion of its discoverer, reticulum 

 Malpighianum, and by means of which chiefly the cuticle is 

 united more firmly to the corium. h 



" Its nature is mucous ; it is very soluble ; and, being thicker in 

 Ethiopians, may be completely separated in them from both the 

 corium and cuticle, and made to appear as a true distinct mem- 

 brane." i 



E Skin and raucous membranes have much relation to each other; and by 

 constant dryness of the latter, and constant moisture and excitement of the 

 former, a great approximation may be effected. 



h *' Hence I have found the epidermis of Albinoes separate easily by the heat 

 of the sun; whereas, in negroes, it scarcely does soon the application of a blister 

 Consult Mitchell, 1. c. p. 108." 



1 " B. S. Alhinus, De sede et causa colons ^thiopum et cceteror. hominum. 

 Lugd. Batav. 1737. 4to. fig. 1. 



Sam. Th. Soemmerring, iiber die fcorperl. Verschiedenh. des Negers vom Eu- 

 ropaer. Ed. 2. p. 46. sq. 



Some even of the moderns have assigned many laminae, and even different 



T 2 



