126 



ON THE BONES, ETC. 



Bion to revert to in a distinct study upon the varieties of the human race,* 

 it is unnecessary to pursue it any farther at present. 



It is a most curious circumstance, that the children of negroes are uni- 

 formly born white, or nearly so ; and that the black pigment which colours 

 them is not fully secreted till several months after birth. It sometimes 

 happens, though rarely, that from a morbid state of the secretory organs 

 there is no pigment secreted at all, or a white pigment is secerned instead 

 of a black ; whence we have white negroes, or persons exhibiting all the 

 common characters of the negro breed in the form of the head and features 

 of the face, with the anomaly of a white skin. And it sometimes happens, 

 though still more rarely, that from a similar kind of morbid action affect- 

 ing the secretory organs, the black pigment is secreted in alternate or 

 interrupted divisions j and in this case we have negro children with brin- 

 dled, marbled, or spotted skins : an instance of which was brought to me 

 by a gentleman about two years ago, who had purchased the child in 

 America, and who, 1 beheve, afterwards exhibited it in this metropolis as 

 a public show. 



The CUTICLE is the thinnest of the layers that form the general integu- 

 ment of the skin. It often, however, becomes thicker, and sometimes 

 even horny, by use. Thus it is always thicker in the sole of the foot and 

 palm of the hand ; and horny in the hands of blacksmiths and dyers ; and 

 still more so in the soles of those who walk barefooted on burning sands. 

 It is annually thrown off" whole by many tribes of animals — as grasshoppers, 

 serpents, and spiders — and as regularly renewed ; and by some animals it 

 is renewed still more frequently : it is shed not less than seven times by the 

 caterpillar of the moth and butterfly before either becomes a chrysaHs. 

 There are a few plants that exfoliate their cuticle in the same manner, 

 and as regularly renew it. The West India plane-tree throws it off 

 annually. 



From the cuticle shoots forth a variety of substances, which either pro- 

 tect or adorn it, the roots of which are not unfrequently imbedded in the 

 true skin itself. Of the harder kind, and which serve chiefly as a defence, 

 are the nails, scales, claws, and horns ; of the softer and more ornamental 

 kinds, are hair, wool, silk, and feathers. 



Hair is the most common production, for we meet with it not only in 

 all mammals, but occasionally in birds, fishes, and insects, varying in con- 

 sistency and fineness, from a down invisible to the naked eye, to a bristle 

 strong enough to support, when a foot long, ten or twelve pounds weight 

 without breaking. 



Wool is not essentially different in its chemical properties from hair, 

 and it varies equally in the fineness and coarseness of its texture. It is 

 generally supposed by the growers, that the fineness of its texture depends 

 upon the nature of the soil ; yet of the two finest sorts we are at present 

 acquainted with, that of Spain and that of New South Wale-!, which last 

 is an offset from the Cajje of Good Bope, and has yielded specimens of 

 broad-cloth, manufactured in this country, as soft and silky as that of un- 

 mixed Merino wool — tha?; of Spain is grown on a pure limestone soil, 

 covered with small leguminous plants instead of with grass ; and that of 

 New South Wales on a soil totally destitute of Ume, and covered with a 

 long, rich, succulent grass alone. 



Food, however, or climate, or both, must be allowed, under certain 



* Series IL Lect. III. 



