Melanin

“ Eiselt of Prague called attention to the fact that in cases of melanotic cancer of the liver, melanine appears in the renal secretion.20 When the urine is passed it is usually quite clear; but after standing it becomes of a dark colour, even as dark as porter, without, however, losing its transparency. This deepening of the colour is no doubt due to the oxidation of the melanotic pigment, as the employment of an oxidizing agent, such as nitric or chromic acid, causes the same change to occur instantly. ”

“ The lips turn pale, the eyes loose their brightness and by degrees the white grows as it were greenish, the gums want their due firmness, with their proper colour; and an unpleasing foulness grows upon the teeth: the inside of the mouth is pale and furred, and the throat dry and husky: the colour of the skin is pale (though there are periods when the face is florid) and as the obstruction gathers ground, and more affects the liver, the whole body becomes yellow, tawny, greenish, and at length of that deep and dusky hue, to which men of swift imagination have given the name of blackness. ”

“ Melanism is an anomaly, the exact contrary of the preceding. It is characterized by the presence in the tissues and skin of an excessive amount of pigment. True total melanism is unknown in man, in whom is only observed partial melanism, characterized simply by a pronounced coloration of part of the integument.
Some curious instances have been related of an infant with a two-colored face, and of others with one side of the face white and the other black; whether they were cases of partial albinism or partial melanism cannot be ascertained from the descriptions. ”

“ It is obvious that, the blacker the pigment, the less light and heat will be transmitted to excite these glands into activity. In the second place, there is a continual transudation of sweat from the minute vessels of the surface of the body through the epidermis at every point. The thicker or the more oily the scarf-skin, the less will the amount of this transudation be. If it be both thick and oily, as in many dark races, the quantity transuded will be reduced to a minimum; if it be thin and not oily, as in the fairest members of the white race, transudation will be copious. ”

“ The human skin develops pigments to protect itself against a strong sun, and the quantity of pigment in the skin varies with the intensity of the sun.
“It is therefore the men who live in the hottest and least shaded parts of the world—that is to say, in the African, that we find the blackest skin. The white peoples, on the contrary, are confined to a region where the humidity of the atmosphere forms a screen against the rays of the sun. Finally, between the Negro and the White, is the Yellow man, who is a product of desiccating grasslands with seasonal extremes of temperature.” ”

“ The sclerotic coat, which in a healthy European is almost what it is called, the “white” of the eye, only takes a slightly yellow tinge among the darkest races, as the African negro. Again, in ordinary eyes of all races, the pupil in the centre of the iris appears absolutely black, being in fact transparent, and showing through to the black pigment lining the choroid coat at the back of the eye. But the iris itself, if examined in a number of types of men, has most various colour. In understanding the coloration of the eye, as of the skin, the peculiarities of albinos are instructive. ”

“ On gray horses that at 10 or 12 years of age are turning white in color, purple-black malignant growths, known as pigment of melanotic tumors, frequently appear where the skin is black in color, and constitute the disease termed melanosis. ”

“ The parts of the body usually bare, as the skin of the face and hands, are darker than others. In the same region, country-people are more tanned than town residents. In latitudes not far apart, the inhabitants of the same country vary in complexion in a measure perceptibly related to the intensity of solar light. In Europe three varieties of color in the skin are distinctly marked: olive-brown, with black hair, beard, and eyes; chestnut, with tawny beard and bluish eyes; blond, with fair, light beard and sky-blue eyes. White skins show more readily alterations occasioned by light and heat ”

“ Now the colour of people depends a little on the colour of their blood, for there is a network of tiny veins in the lower part of their skin, but it depends even more on millions of little specks of yellowish and brownish paint which lie in the upper part of their skin. A negro may be as black as your hat outside, but his blood is red all the same, and he looks black because the little specks of paint in the upper part of his skin are very dark and hide the red blood behind them. ”

“ The colouring of the dark races appears to be similar in nature to the temporary freckling and sun-burning of the fair white race. Also, Europeans have permanent dark colouring in some portions of the skin, though not exposed to the sun; the areola of the breast, for instance; while in certain affections, known by the medical name of melanism, patches closely resembling negro skin appear on the body. On the whole it seems that the distinction of colour, from the fairest Englishman to the darkest African, has no hard and fast lines, but varies gradually from one tint to another. ”

“ As for the adrenal superiority of the white man, "it is 150 years since John Hunter came to the conclusion ... that the original color of man's skin was black, and all the knowledge that we have gathered since his supports the inference he drew. From the fact that pigment begins to collect and thus darken the skin when the adrenal bodies become the seat of a destructive disease we infer that they have to do with the clearing away of pigment, and that we Europeans owe the fairness of our skins to some particular virtue resident in the adrenal bodies." ”

“ Among the Jews who have settled in Northern Europe, are many of light complexion, while those who live in India are as dark as the Hindoos. Intense heat also increases this coloring matter, and thus a furnace-man's skin, even where protected by clothing, becomes completely bronzed. The black pigment has been known to disappear during severe illness, and a lighter color to be developed in its place. Among the negroes, are sometimes found people who have no complexion, i. e., there is no coloring matter in their skin, hair, or the iris of their eyes. ”

“ While dark-haired people show pigmentation in a very marked manner, those with red hair show it slightly or not at all. In some peculiar manner red-­haired people appear to possess a comparative immunity to the effects of intestinal stasis. Except for the face, the areas that show pigmentation most conspicuously are those exposed to friction, such as the inner aspects of the upper parts of the thighs, with the adjacent opposing surfaces of the buttock, the spines and abdomen where the corset or dress presses, the axillary folds, the bend of the elbow, and the neck. ”

“ The general fact of increasing nigrescence from temperate towards equatorial regions is conspicuous enough, despite some irregularity of the shading.53 This fact points strongly to some direct relation between climate and pigmentation, but gives no hint how the pigmental processes are affected. The physiologist finds that in the case of the negro, the dark skin is associated with a dense cuticle, diminished perspiration, smaller chests and less respiratory power, a lower temperature and more rapid pulse,54 all which variations may enter into the problem of the negroes coloring. ”

“ The patient becomes intensely weak, muscular movement becomes impossible, intellectual processes cause great fatigue, and finally blood pressure becomes so low that fatal collapse ensues from lack of blood in the brain. The external symptoms of these cases is a pigmentation, that is, a very dark discolouration of the skin, which develops rather early in the disease. The tongue especially becomes a very dark brown. Areas of pigmentation also occur where the skin is irritated,—at the wrists from the irritation of the coat sleeves, at the edge of the hair from the irritation of the hat. ”

“ Yet from the very happy circumstance of the conspicuousness of the pigment, the results of their activity could be observed with the utmost facility, and their behaviour in relation to inflammatory congestion easily studied even under a low magnifying power.
The pigment cells pervade the skin and subcutaneous tissue of which the frog's web consists, and are especially numerous about the blood-vessels, round which their branches twine abundantly. They must, therefore, be acted on along with the vascular parietes by anything applied to the surface of the membrane. ”

“ In fair individuals with blue eyes and a pink and white skin, the pigment seemed to be entirely wanting. In individuals with a brown skin, black hair, and a very dark iris, “not only the brain enveloped by its membranes assumes a deeper shade, but a layer of black matter, in every way comparable to that of the Negro, covers the protuberance, the pineal gland, and some other points of the nervous centres.” ”

“ It would seem as if the blackness is associated with the general thickening of the skin and is an accompaniment of the general organic adaptation of the negro to his hot malarious climate. The effects of sunburn vary with different races. It is with the races having intermediate pigmentation, such as the dark Europeans and the yellow peoples, that the effect is most noticeable. With the former the sun burns the skin uniformly, making them of the tint of mulattoes. ”

“ In all races there occur abnormal varieties, which should be observed with reference to their being hereditary, such as Albinos, whose dead-whiteness is due to absence of pigment from the skin. Even such tendencies as that to the occurrence of red hair where the ordinary hue is black, or to melanism or diseased darkening of the skin, are worth remark. ”

“ There are some cases on record where emotional states have caused loss of pigment in the negro or other colored races, or in the hair, as when, in well-substantiated cases, people's hair has become white in a single night. In every case of pigmentary disturbance, then, the individual must be carefully studied and as far as possible all emotional disturbance must be eliminated. ”

“ The skin rested, as did the brain, so that it seemed probable that central activity, thought, will, or whatever name is given, has some effect in the change of color. The probability is that, as they become pale, the pigment does not leave the skin, but that it is collected in spheres too small to affect our retina, which will be impressed by the same quantity of pigment when more extended. ”

“ The reason is, that in him the pigment allows the slightest differences in the afflux of blood to the dermis to be perceived. With the Negro as with us, the blood has its share in the colouring, the tint of which it deepens or modifies. ”

“ However, to return to the Query: the term pale is applied to the yellow-tinted skin; fair, to the red or pink; brown, to the mixture of red and yellow, with either blue or such darkness as above described; sallow, to yellow and darkness; and the only close approach to whiteness that we ever see, is in the sick room of the long-suffering fair complexion. In death, this changes to a "blackish grey," a mixture of white and darkness.
The pale complexion indicates a thick, hard, dry skin; the fair, a thin and soft one ”

“ These findings are the more noteworthy by reason of their contrast to the usual deep pigmentation of the Indian eye. Some of our specimens throw light on this phenomenon, for we observe in them two changes: (1) The pigmentary layer of the retina is irregularly thinned and altered, and at some points its pigment can be seen migrating into the choroid; (2) the choroidal pigment itself is extensively altered in an irregular manner, being heaped up in some areas and thinned in others. ”

“ It is a very rare disease. Both Negroes and Caucasians occasionally have it, but it is naturally more conspicuous on blacks than whites. It absolutely removes skin pigment and sometimes it turns a Negro completely white but only after a period of thirty or forty years. It occurred to me that if one could discover some means of artificially inducing and stimulating this nervous disease at will, one might possibly solve the American race problem. ”

“ Between the two is placed the mucous layer, of which the pigment alone in reality varies in quantity and colour according to the race.
All the colours presented by the human skin have two common elements, the white of the dermis and the red of the blood. Moreover, each has its own proper element, resulting from the colourings of the pigment. The rays reflected from these different tissues combine into a resultant which produces the different tints and traverses the epidermis. ”

“ The colour of the human skin has always held an important place among physical criteria of race. Physiology explains colour as a consequence of climate and even diet. The pigment or colour- ing matter under the epidermis, or rather under the second or Malpighian skin, is not peculiar to the Negroid and other coloured races, but is common to all human beings. ”

“ Do you know one way we can tell if all the organs are doing their work well? By watching for the sign language. If the blood is not carrying the skin sufficient nourishment, it will be very pale and dull looking. If the waste materials are not being carried off, they may accumulate in the skin and clog the pores. Then we will have pimples or blackheads. Each person's skin is a law unto itself, and what is beneficial to one may not be to another. ”