CUTANEOUS SYSTEM OR SKIN. 193 



the air. Rain is, no doubt, caused in the same manner. Dr. Smith 

 has performed some interesting experiments on the subject of ex- 

 halation, from the skin and lungs jointly. Eight workmen in the 

 Phoenix Gas-works, London (where they must work hard, and be 

 exposed to a high temperature at the same time), were weighed 

 before going to work, and immediately afterwards. In one experi- 

 ment, in November, they continued to work for an hour and a quar- 

 ter, and the greatest loss sustained by any one man was two pounds 

 fifteen ounces. In another experiment, in the same month, one 

 man lost four pounds three ounces in three quarters of an hour ; 

 and in an experiment of the same kind, in June, one man lost no 

 less than five pounds two ounces in an hour and ten minutes. 



We shall conclude this chapter by stating a few other circum- 

 stances connected with the structure and functions of the skin. 

 We have mentioned that the external layer of the skin is called the 

 cuticle. M. Breschet^ a French author, who has very carefully 

 investigated the structure of the skin, considers the cuticle to be of 

 the same nature as the horny matter which forms the nails, the 

 hairs, feathers, horns, &c., of animals. It is secreted by particular 

 organs, and when intended to be colored, it is mixed with coloring 

 matter (which also is secreted by distinct organs) while in a fluid 

 state. The arrangement of the cuticle, in different parts of the 

 human body, is well worthy of attention. Where feeling is to be 

 exercised, it is thin and delicate ; over the joints it is lax and mov- 

 able ; on the palms of the hands and soles of the feet, even in the 

 infant, it is thick and hard, and these properties are greatly in- 

 creased by constant use. Simple as this last provision may appear, 

 it seems doubtful whether the want of it would not have interfered 

 materially with the exercise of many of our most useful arts. 



Between the cuticle and the true skin, formerly mentioned as the 

 part of animals that is tanned, is found the layer that gives the color 

 to the different varieties of the human species, &c. (rete mucosum.) 

 In Europeans it is generally of a light color, in Negroes it is black, 

 and in other races it is intermediate, or of other shades. The color 

 of the Negro does not depend on the blackening of the cuticle by 

 the sun, for his cuticle is seen to be as transparent as an European's 

 when raised by a blister ; and we observe, also, that the secretion 

 of the black coloring matter does not take place in the Negro child 

 until a day or two after birth. The change of color in the human 

 family, I have no doubt, took place at the confounding of the lan- 

 guages at the tower of Babel. It is all nonsense to suppose that 

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