"The whole human appearance is still more diversified by the state of society, in which different tribes of our race exist, and by their manner of living, the influence of which causes, deserves to be more minutely examined. Hence, I shall now pass under review the general effects of climate upon the colour of the human skin; then notice the principal, apparent deviations from the common law, exhibited in various portions of the earth.

"The power of climate to change the complexion, is demonstrated by facts which constantly occur to our own observation. In the summer season we perceive, that the intensity of the sun's rays in this temperate latitude, tends to darken the colour of the skin, especially among the labouring poor who are more constantly than others, exposed to their action. In the winter, on the other hand, the cold and keen winds which then prevail, contribute to chafe the countenance, and to excite in it a sanguine and ruddy complexion. The degree, in which the one or the other prevails over its opposite, may be considered as a constant and uniform cause to the action of which the constitution is exposed.

"Heat and cold affect the nervous system by tension or relaxation, by dilation or contraction, and in this way produce an alteration in the state of the solids. Hence also the fluids are affected; the quantity of the perspiration is augmented or diminished; and the proportions of the various secretions changed. But the human skin is susceptible of still greater and more sensible changes by the opposite actions of the intense rays of the sun, or of the principle of cold upon its delicate texture. These effects, in countries where heat and 'cold succeed each other in nearly equal proportions, are transient and interchangeable. But, where the climate, in any given proportion, repeats the one or the other of these impressions, there, in the same degree, is formed a correspondent and habitual colour of the skin.

"The dark colours of the tropical nations, however, are not to be ascribed solely to the action of the sun's rays upon the skin. Extreme heat, especially when united with putrid animal, or vegetable exhalations, which in all torrid climates are found copiously to impregnate the atmosphere, tends greatly to augment the secretion of bile in the human system, which being diffused over the whole surface of the body, imparts to the complexion a dull yellowish tinge, that soon assumes a very dark hue by being exposed to the sun, and

by immediate contact with the external air. Different shades of the dark colours, therefore, till we arrive at the deepest black, will be found in the human complexion, in proportion to the predominancy of bile in the constitution, as well as of heat in the climate."

STRUCTURE OF THE HUMAN SKIN.

tr I shall now make a preliminary remark on the structure of the skin, the seat of colour. The human skin has been discovered by anatomists to consist of three distinct lamellæ, or integuments :-the external, or scarf-skin, which is an extremely fine netting, and perfectly transparent in the darkest coloured nations:-the interiour or true skin, which in people of all the different grades of colour, is white:and an intermediate membrane which is cellular in its structure, somewhat like a honey-comb.-This membrane is the proper seat of colour, being filled with a delicate mucous, or viscid liquor, which easily receives the lively tinge of the blood when strongly propelled by any cause to the surface, or the duller stain of the bile, when it enters in any undue quantity into the circulation. The smallest surcharge of this secretion imparts to it a yellowish appearance, which, by remaining long in contact with the atmosphere, assumes a darker hue; and, if exposed, at the same time, to the immediate influence of the sun, approaches, according to the heat of the climate and the degree in which the bile prevails, towards black."

GENERAL DIVERSITIES AND CAUSES OF

COMPLEXION.

"Encircle the earth in every zone, and make 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, and each zone is seen to be marked by its own distinctive and characteristick complexion. The black prevails under the equator ;-near the tropicks we arrive at the dark copper;-and on this side of the tropick of Cancer to the seventieth degree of nothern latitude we successively

trace the tawny, the olive, the brown, the fair, the sanguine. In each of these grades we discover several shades or tints; till, beneath the arctick circle, we return to the black. This general uniformity in the effect, as we proceed towards the North, or the South, affords a strong presumption, that the various shades of complexion which distinguish the different latitudes, are to be ascribed chiefly to the influence of climate. The apparent deviations from this law which are presented to our view in particular regions of the globe, will, when we come in the progress of this discourse to point out their causes, serve only to confirm the general principle.

"The influence of climate on the human complexion, is demonstrated by well known and important events within the memory of history. From the Baltick to the Mediterranean the different latitudes of Europe are marked by different shades of colour. In tracing the origin of the fair German, the dark coloured Frenchman, the swarthy Spaniard and Sicilian, it has been proved, that they are all derived from the same primitive stock; or, at least from nearly resembling nations which may be comprehended under the general names of Huns and Goths. The southern provinces of France, of Italy, of Spain, and of other countries in Europe, are distinguished from the northern by a much deeper shade of complexion. And, if we extend our view beyond Europe to the great empires of the East, to Arabia, to Persia, to India, and China, this observation is still more applicable to those countries which embrace so much greater an extent of latitude.

"The inhabitants of Pekin are fair, while those of Canton exhibit as deep a colour as the Mexicans. The Persians in the vicinity of the Caspian sea, are among the fairest people in the world; and their neighbours, the Georgians and Circassians, are acknowledged to be the most beautiful. But this delicate complexion gradually changes to a dark olive as we approach the gulf of Ormus. The inhabitants of the stony and desert Arabia, are distinguished by a light copper colour, while those of the southern provinces of Mocha and Yemen, are of as deep a hue as those of middle India. The same gradation holds in Egypt, from the Mediterranean sea to the foot of the mountains of Abyssinia. The population of the southern provinces of the peninsula of India, are black; on the North and just below the range of the Caucasian mountain is, the complexion changes to a

light chestnut, or yellow colour. And this gradation is observed both on the Malabar and the Coromandel coast. But no example can carry with it greater authority on this subject than that of the Jews, who, though descended from one stock, are marked with the peculiar characteristicks of every climate, and exhibit the fair, the brown, the swarthy, the olive, the tawny or copper colour, and even the black. And indeed the diversified peculiarities of children in the same family, favour the doctrine of the identity of the origin of different nations, though one is black, another red, and another white. From such examples, at least, we derive a practical proof, that there is in human nature a susceptibility of great varieties which may be incorporated into the constitutions of families, and of nations, without impairing any of the essential properties of the species."

SOME PECULIARITIES OF THE HUMAN HAIR.

"The peculiarity of hair, now demanding our attention, is that spare, coarse, and involved substance like wool, which covers the head of the tropical African. But its spareness or coarseness is analogous to effects which are constantly seen to be produced by the temperature of arid climates upon the different species of animals. Its involution may be occasioned in part by the excessive heat of a vertical sun, acting upon sands which glow with an ardour unknown in any other quarter of the globe. It may nevertheless be occasioned chiefly by some peculiar quality of the secretion, by which it is nourished. That the curl, or nap of the hair, depends in a great degree upon this cause, is rendered the more probable by the appearance which it exhibits on the chin, over the armpits, and other parts of the human body. The hair or wool is becoming less involved among the negroes born in these United States, and especially among the domestick servants who are well fed, and clothed; and who are bred in the habits of all the neatness and cleanliness which prevail in the mansions of their masters. And many of those of the third and fourth class of the descendants of African ancestors by carefully dressing it, frequently extend it in a braid or cue of several inches in length.

"Suffer me to relate an anecdote, mentioned by Dr.

William Barton of Philadelphia, and which demonstrates, that the involution and woolly nature of the hair of the African negro, depend in a great degree, if not chiefly, on the quality of its nutriment in the skin. Henry Moss, a negro in the state of Maryland, began, upwards of twenty years ago, to undergo a change in the colour of his skin, from a deep black, to a clear and healthy white. The change commenced about the abdomen, and gradually extended over different parts of the body, till, at the end of seven years, the period at which I saw him, the white had already overspread the greater portion of his skin. It had nothing of the appearance of a sickly, or Albino hue, as if it had been the effect of disease. He was a vigorous and active man, and had never suffered any disease either at the commencement, or during the progress of the change. The white complexion did not advance by regularly spreading from a single centre over the whole surface; but, soon after it made its first appearance, it began to show itself on various parts of the body, nearly at the same time, whence it gradually encroached in different directions on the original colour, till at length, the black was left only here and there in spots of various sizes and shapes. These spots were largest and most frequent, where the body, from the nakedness of the parts, or the raggedness of his clothing, was most exposed to the rays of the sun. This extraordinary change did not proceed, by gradually and equably diluting the intensity of the shades of the black colour over the whole person at once; but the original black, reduced to spots when I saw it, by the encroachments of the white, resembled dark clouds insensibly melting away at their edges. The back of his hands, and his face, retained a larger proportion of the black than other parts of his body; of these, however, the greater portion was changed. And the white colour had extended itself to a considerable distance under the hair. Wherever this took place, the woolly substance entirely disappeared, and a fine, straight hair of silky softness succeeded in its room. Hence that secretion in the skin which contributes chiefly to the formation of the negro complexion, seems to be the chief cause also of the curl, or woolly appearance of the hair.

Although the principal cause of the peculiar form of the African hair, consists in those secretions which, being deposited in the cells of the skin, become the nutriment of this