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bile which is requisite to its safety, and its comfortable subsistence in its new situation.*

In the preceding propositions I have endeavoured to state some principles, supporting them on the authority of unquestionable facts, by which to explain the proximate cause of colour, and its various shades in the human species, but, whether the theory which I have attempted to erect on the foundation of these facts be satisfactorily supported or not, the general principle, that climate possesses all the power to change the complexion which I have ascribed to it,

[footnote] *Bilious disorders are known to relax the system, and thereby to render it less liable to the inflammatory fevers to which a tense and plethoric habit would be exposed under a hot sun. The bile which tends easily to become mucous and incrassated, contributes also, by increasing the thickness of the skin, which thereby forms a kind of veil to the body, to resist, the inflammatory action of the sun's rays upon the constitution, and to render it more patient of extreme heat. For, it is observed by Blumenbach, of the reticular membrane of the skin, that it is always thicker in proportion to the darkness of the colouring matter with which its cells are filled. Blum. de gen. %c. p. 164.

But it should ever be remembered that the predominance of bile in the habit, and the discolouration of the skin, although they may be, and, in the first instance, usually are, the effects of disease, yet, becoming, in time, constitutional properties, they remain after all symptoms of disease have passed away; and may even become necessary to a healthful state of the body. [[/footnote]]

can be established, I apprehend, on the clear and decisive evidence of other facts, although I should have failed to point out the precise mode in which climate acts, or accurately to have traced the chain of its effects. -The principle results, then, from the regularity of the complexional zones of the world. - It results from obvious and undeniable events within the memory of history. - And it results from facts which come under our own immediate observation in America.

Encircle the earth in every zone, and, making those reasonable allowances which ought to be made. For the influence of mountains, lakes, and seas, and those other circumstances which are known to modify the temperature of climate, each zone is seen to be marked by its own distinctive, and characteristic complexion. The black prevails under the equator; - near the tropics we arrive at the dark oopper; - and, on this side of the Tropic of Cancer, to the seventieth degree of northern latitude, we successively trace the tawny, the olive,* the brown,

[[footnote]] * Some difference exists in the tints which mark the corresponding latitudes in Asia and Europe, arising from the diversity of the respective climates occasioned by the nature of the soil, the form of the continents, and other causes affecting the temperature of the atmosphere. [[/footnote]]