given angle a right angle; and the complement of a number is a number which would, by addition, make the given number equal to the next higher unit. 623,741 and 376,259 are complements of each other.

COMPLEXION (Lat. complexio), the color of the skin. This color exists in the epidermis alone, and depends upon the admixture of pigment cells with the ordinary epidermic cells. The ancient anatomists very properly divided the skin into 2 parts or layers, the inner being denominated the cutis or dermis, and the outer the cuticle or epidermis. The celebrated anatomist Malpighi was the first to discover what was thought to be a third layer interposed be tween the cutis and the cuticle, to which the name of rete mucosum, or stratum Malpighii, was applied, from the circumstance that it was supposed to furnish mucus to lubricate those papilla with which it was placed in immediate contact. M. Flourens, in an elaborate memoir on this subject, made to the French academy, went beyond Malpighi and divided this middle portion of the skin into 4 layers: 1, one lying immediately on the cutis, of a cellular structure; 2, a continuous membrane present ing the characteristics of mucous membranes generally, on the external surface of which is spread a black pigment which constitutes the 3d layer; and 4, the inner portion of the epidermis lying contiguous to the coloring matter. M. Flourens displayed by maceration all these layers in the skin of a negro; but on subjecting that of a white man to the same process, he was unable to discover the pigment or the mucous membrane deposited upon it. He therefore concluded that the skin of the colored races has an apparatus entirely wanting in the white, and regarded this diversity as forming a specific distinction, marking the European and negro as belonging to separate species; an opinion which, if the fact were true, would not admit of question, for, as Prichard properly remarks, the endowment of an entirely peculiar organ to one race of which no traces are to be found in the proximate tribe, is a much greater difference than is often to be found on comparing species which stand next to each other in the zoological series. There are many facts, however, well known to medical men, which do not admit of explanation upon M. Flourens's theory. Among these are the discolorations which take place in the skin of European races, in certain disordered states of the constitution. During pregnancy many females have a dark tinge around the nipples, varying in intensity in different cases, and in some the entire abdomen is covered with a hue as dark as that of the African negro. Bomare mentions a case of this kind in the person of a French peasant, whose abdomen became completely black during each pregnancy. Camper likewise gives an account of a female of rank who had naturally a white skin and beautiful complexion, which whenever she became pregnant began to grow brown. "Toward the end of pregnancy," he

says, " she became in color a veritable negress," After delivery, the dark color gradually disap peared. Dr. Starck mentions the case of a man who after an attack of intermittent fever be came as black as a negro. Blumenbach pos sessed a part of the skin taken from the abdomen of a beggar, which was as black as that of an African. Elliotson relates the case of a girl in St. Thomas's hospital, whose family were all white, but whose left shoulder, arm, and hand were of negro blackness, except that a stripe of white ran between the elbow and armpit; also that of a white woman, who in 20 years became as black as a negress without any evident reason. A case is related in the Jour nal général, where a woman became suddenly black from mental distress, and remained so. The blackness in this case was not caused by jaundice, or congestion of blood, but by a change in the coloring matter of the rete mucosum. The "Transactions of the Medical Soci ety of the State of New York," for 1858, contain a case of a change of color in the person of a female, aged 16 years, the daughter of a respectable farmer, reported by Dr. W. H. Gardiner. When the patient was first seen by Dr. Gardiner, Sept. 15, 1857, the discoloration of the skin had existed for about 4 years, and she presented in color the appearance of a dark mulatto with distinctly marked European features. Her father was of English, and her mother of American birth; both had light com. plexions, with light eyes and brown hair. All their children resembled them in complexion except the patient of Dr. Gardiner, who pos sessed the same complexion as her brothers and sisters until she had attained her 14th year. Soon after puberty some dark brown spots were observed upon her forehead, which looked at a little distance as if covered with fine dust. These spots were not constant, nor did they attract much attention until they had been present about 2 years. At the age of 16, after an attack of slight illness, her complexion grew rapidly darker, and in about 2 months had acquired the deep hue which it afterward bore. At this period she presented, when at a short distance, the appearance of a white person whose skin had been covered with a thin coating of lamp-black, through which some appear ance of the hue of the surface was apparent, with here and there spots, from a few lines to a fourth of an inch in diameter, which were as black as the skin of the darkest African. On removing the cuticle from one of these spots, it was found to be overspread with a pigment which had much the color of lamp-black mixed with mu cilage. The hair had changed from its original brown to black, and become coarse and straight. Her eyes were of light hazel, the whites presenting that pearly appearance peculiar to the colored races. Every portion of the surface was free from an icteritous tint. She died in the early part of Oct. 1857, from disease apparently in no way connected with the discoloration of the skin. These facts show that a physical

change may take place by means of which the skin of an individual of a white race may become as black as that of the native of Africa, The coloring matter is likewise liable to be absorbed in the skin of those to whom it is natural, and instances are not uncommon of negroes who gradually lose their black color, and become as white as if they were the offspring of parents of another race. The "Manchester Memoirs" contains the case of a negro 40 years of age whose skin had so changed in 2 years that the narrator was convinced that all the black portions remaining did not exceed a square foot, and the change was then continuing very rapidly. The "Philosophical Transactions" contain the case of a negress in Maryland 40 years of age who had been turning white for 15 years, and had become in that time scarcely inferior in any part of her surface to a European. Another instance is related in the "Philosophical Transactions" of a boy born in Virginia of black parents, who continued of his native color until he was 8 years of age, at which time a change began to take place, although the boy's health continued good. At first white specks made their appearance on his neck and breast, which soon increased in number and size so that from the upper part of his neck to his knees he was completely dappled. Dr. Barton relates the case of Henry Moss, a negro, in the state of Maryland, whose skin had undergone a complete change from a deep black to a clear and healthy white. The change commenced about the abdomen, and gradually extended over the different parts of the body, so that in 7 years it had spread over a greater part of the skin. It had not the appearance of a sickly or albino hue as if from the effect of disease, but was of a healthy aspect. He had never suffered from disease, and during this change, which was gradual and frequently irregtlar, he continued in robust health. A curious case of change of complexion is narrated by Dr. Hutchinson, of Kentucky, in the January number of the " American Journal of Medical Sciences" for 1852. The subject of this notice was a slave belonging to Mr. B., and aged 45. He was born of black parents, and was himself perfectly black until the age of 12. At that time a portion of the skin an inch wide, encircling the cranium just within the edge of the hair, gradually changed to white, also the hair occupying that locality. A white spot next appeared near the inner canthus of the left eye, and from this the white color gradually extended over the face, trunk, and extremities, until it covered the entire surface. The complete change from black to white occupied about 10 years, and but for his hair, which was crisped or woolly, no one at this time would have supposed that his progenitors had any of the characteristics of the negro, his skin presenting the healthy vascular appearance of a fair-complexioned European. When about 22, dark-colored or brown spots began to appear on the face and hands, being limited as they are at present to

those portions of the surface exposed to light. Thus it appears that the coloring matter that gives rise to the various hues in the complexion is sometimes produced in the skin of persons born white, and at others removed from those born black. Now it is hardly possible, in view of these facts, to suppose with M. Flourens that the discoloration which takes place in the skin of the white person is totally different in kind and has its seat in a different structure from that which produces the black or tawny hue in the colored races. All the analogies are against such a supposition, which requires the adduction of the most positive testimony to sustain it.-Microscopical investigations have done much to solve the doubt that hangs over this question. Henle, in examining the skin of the negro by the aid of the microscope, discovered, beside the order of cells usually found, others containing the black pigment which imparts the color to the African's skin. He found these last aggregated especially on those parts of the rete mucosum which project and correspond with the furrows of the surface of the cutis. Dr. Simon, of Berlin, took pains to ascertain whether the discolorations which occasionally take place in the skin of persons of European extraction depend upon the presence of similar cells filled with pigment; and in examining the discolored portions of such skins, as the areola around the nipple, he found that the discolorations depended on the presence of cells filled with pigment in the rete mucosum. The shape and size of these cells correspond with those described by Henle as existing in this portion of the skin of the African, and which imparts to it its peculiar color. Dr. Simon also examined many of those abnormal discolorations that take place in navi materni, or congenital spots, moles, and summer freckles, and found in each that the coloring substance was contained in the rete. All of these discolorations are related therefore, Dr. Simon concludes, to the normal and natural colorations in the skin of the negro. The rete mucosum, which derives so much importance from its being the seat of the coloring matter that gives rise to the varieties of complexion observable among the different races of mankind, is found by more recent microscopical researches, and especially those of Kolliker, not to be a distinct structure, but to consist of the more recently formed parts of the epidermis, whose cells are not yet consolidated by the for mation of horny matter in their interior. The pigment cells which secrete coloring matter, as first shown by Dr. Simon, are not readily distinguishable in the epidermis of the white races except in certain parts of the body, as around the nipple, but are quite perceptible in the new layers of the epidermis of the negro. It was supposed by Dr. Simon that these cells gradually become flattened, and passing to the surface give the dark tint observable in the colored races. The more recent examinations of Kolliker establish the fact that the cells containing coloring material do not change their place, but

remain stationary in that portion of the epidermis in which they were first developed. Dr. Carpenter says: "The epidermis or cuticle covers the exterior surfaces of the body as a thin, semi-transparent pellicle, which is shown by microscopical examination to consist of a series of layers or cells, which are continually wearing off at the external surface and are being renewed at the surface of the true skin, so that the newest and deepest layers gradually become the oldest and most superficial, and are at last thrown off by desquamation. In their progress from the internal to the external surface of the epidermis, the cells undergo a series of well-marked changes. When we examine the innermost layer we find it soft and granular, consisting of nuclei in various stages of development into cells, held together by a tenacious semi-fluid substance. This was formerly considered as a distinct tissue, and was supposed to be the peculiar seat of the color of the skin; it received the designation of rete mucosum. Passing outward, we find the cells more completely formed; at first nearly spherical in shape, but becoming polygonal where they are flattened one against another. Mingled with the epidermic cells we find others which secrete coloring matter instead of horn; these are termed pigment cells. The most remarkable development of pigment cells in the higher animals is on the inner surface of the choroid coat of the eye, where they have a regular arrange ment, and form several layers known as pigmentum nigrum. The black color is given by the accumulation within the cells of a number of flat oval or rounded granules of extreme minuteness, which exhibit an active movement when set free from the cell, and even while enclosed within it." Quain and Sharpey say: "Many of the cells of the cuticle contain pigment, and often give the membrane more or less of a tawny color, even in the white races of mankind. The blackness of the skin of the negro depends entirely on the cuticle. The pigment is contained principally in the cells of the deep layer or rete mucosum, and appears to fade as they approach the surface, but even the superficial part possesses a certain degree of color."-Exposure to light exercises a marked influence over the development of the pigment cells of the skin, and hence many persons become spotted with brown freckles under the stimulus of a summer sun. In the same manner the light skin of the European acquires a swarthy hue when exposed to a long continuance of the sun's rays in a tropical climate, which is due to a development of dark pigment in the cells of the cuticle. Bishop Heber, in his observations on India, states that "it is remarkable to observe how surely all these classes of men (whitePersians, Greeks, Tartars, Turks, and Arabians) in a few generations, even without intermarriage with the Hindoos, assume the deep olive tint, little less dark than the negro, which seems natural to the climate. The Portuguese have, during 300 years' residence in India, become

as black as Caffres." "The hottest portion of the globe," says Dr. Pickering, "appears to be about 17 degrees in width, counting from lat. 27° N., and extends from the Atlantic to the Ganges. One-third, perhaps, of this immense tract is inhabited by the white race, although under a physical aspect that would not readily be recognized by Europeans. The complexion, always dark, is in frequent instances sufficiently so to conceal a flush; indeed, the Malay brown complexion seems to preponderate, and I have seen Arabs of deeper hue who were apparently of unmixed descent. In short, the white race is here protean or polymorphous, and exhibits a diversity in feature and complexion that I have not found in the other races." Dr. Smith says that the influence of climate on the human complexion is demonstrated by well-known and important events within the memory of history. From the Baltic to the Mediterranean the different latitudes of Europe are marked by different shades of color, and in tracing the origin of the fair German, the dark-colored Frenchman, and the swarthy Spaniard and Sicilian, it has been proved that they are all derived from the same parent stock, or at least from nearly resembling nations. The southern provinces of France, of Italy, of Spain, and of other European countries, are distinguished from the northern by s much deeper shade of complexion; thus, the traveller through Spain will discover that while the ladies of the province of Biscay possess fair complexions, those of Granada and the southern provinces are endowed with that dark, swarthy hue which the Spaniard considers as constituting one of the chief elements of beauty. The Georgians and Circassians, who are acknowl edged to be the fairest people on the globe, when transferred to a residence in Constantinople, lose their delicate complexion and gradually acquire a sallow hue, which, in their descendants, becomes a dark olive. But perhaps the most striking example is furnished by the Jewish race, who, by their prohibition to intermarry with other nations, form a distinct people in every quarter of the globe, and yet show noticesble shades of complexion in different climates. The native population of the United States furnish a strong illustration of the influence of climate over the complexion. Deriving in a great part their origin from the more northern nations of Europe, and especially from the English and Irish, whose complexions are remarkably fair, they are found to differ from their ancestors in this respect in a very material degree. A certain paleness of countenance, differing entirely from the marked white and red of the English, strikes the observant traveller at every step of his progress through the United States The elevated temperature of the lowlands in Virginia and Maryland, especially near the seacoast, greatly contributes to impart a darkness to the complexion which, when associated with the paleness so common to the whole popula tion of the United States, removes them in a most marked manner from their British ances

tors. It is very easy to distinguish the natives of the eastern shore in Maryland, and of the counties contiguous to the ocean in Virginia, from their brethren who inhabit the more elevated districts in these states, as much by the marked sallowness of the complexion of the former as by their excitable temperament and spare habit of body. Going still further south, along the sea-coast of Georgia and the Carolinas, it is not unusual to meet with individuals, especially among those who are much exposed to the influence of the sun, who are but a few shades lighter than the aboriginal tribes who formerly peopled these states. "If," says Dr. Barton, "these remarkable changes are wrought on the system in the term of a few years, we ought not to be surprised at seeing even the most opposite tints and features produced from the long and permanent operation of moral and physical causes." Yet notwithstanding the influence exerted by heat in darkening the complexion, it is nevertheless true that many light nations are found inhabiting the warmest regions, while there are dark ones resident in the coldest. Lord Kames, M. de Virey, and Prichard have quoted many instances of this kind. "We found," says Humboldt in his "Political Essay on New Spain," "the people of the Rio Negro swarthier than those of the lower Orinoco, and yet the banks of the first of these rivers enjoy a much cooler climate than the more northern regions. In the forests of Guiana, especially near the sources of the Orinoco, are several tribes of a whitish complexion, the Guiacos, Guajoribs, and Argues, of whom several robust individuals, exhibiting no symptom of the asthenical malady which characterizes albinos, have the appearance of true mestizos. Yet these tribes have never mingled with Europeans, and are surrounded with other tribes of a dark brown hue. The Indians in the torrid zone, who inhabit the most elevated plains of the Cordilleras of the Andes, and those who are under lat. 45 S., have as coppery a complexion as those who, under a burning climate, cultivate bananas in the narrowest and deepest valleys of the equinoctial region." "Do we not in fact behold," says Virey, "the tawny Hungarian dwelling for ages under the same parallel and in the same country with the whitest nations of Europe, and the red Peruvian, the brown Malay, the nearly white Abyssinian, in the very zones which the blackest people in the universe inhabit? The natives of Van Diemen's Land are black, while Europeans of the corresponding northern latitudes are white; and the Malabars, in the most burning climate, are no browner than the Siberians." The temperature of a place, however, depends not only on its latitude, but on its elevation and its meteorological conditions. For these reasons the lines of equal temperature do not always agree with the same degrees of latitude, nor are they measured by the widest range in the thermometer. Now, although the elevation of temperature in Africa may not at any one time be VOL. V.-37

greater than is sometimes observed in America, yet there can be no doubt that the annual amount of heat far exceeds that found in the tropical latitudes of the western continent. (See CLIMATE.) In measuring the effect of any particular climate upon complexion, therefore, it is necessary not only to determine its absolute degree of latitude, but also to ascertain what other causes are in operation tending to bestow & deeper or lighter shade upon the human countenance. It is a well-known fact that the luxuriance of vegetation is not so much dependent on the intensity as on the mean quantity of heat; and the same law which operates in effecting a distribution of plants over the surface of the globe independent of well defined lines of latitude, likewise exercises its influence in determining the intensity of shade observable among the different races of mankind. Those nations most exposed to the weather and furthest removed from civilization are, as a general rule, the darkest. Thus the South sea islanders, who seem to be of one family, vary in complexion according to the degree of their civilization. The New Hollanders, who are savages, are black; the New Zealanders, half civilized, are tawny; the Friendly islanders are frequently of an olive color; while the people of Otaheite and the Society islanders, who are the furthest advanced in civilization, are often possessed of a light complexion and flowing ringlets, and sometimes are considered really beautiful. The same fact is observable among persons of different degrees of cultivation in countries having complete and absolute divisions of rank. Thus the nobility of France, Spain, Italy, Germany, and England are not only easily distinguished from the peasantry, but the intermediate classes are as readily determined. An interesting fact connected with this subject is, that the children of those most exposed to the influence of the sun among the white races, and even the offspring of many who possess a tawny color, are as fair at birth as those of the most delicately complexioned parentage. The children of the Moors are born white, and acquire the complexion of their parents in after years. Russell says that the inhabitants of the country in the vicinage of Aleppo are naturally of a fair complexion; and among the women in the upper ranks of life this fair skin is preserved through life, while the inhabitants of that country are generally tinged with a shade which, although lighter than the negro, is deeper than that of the Telingan.-The division of mankind by Blumenbach into the 5 varieties of Caucasian, Mongolian, Ethiopian, American, and Malay, is, among other characteristics, largely founded on difference in complexion. The Caucasian is, for the most part, characterized by a white skin and red cheeks; the hair of a nut-brown, running on the one hand into yellow, and on the other into black, soft, long, and undulating. To this variety belong all European nations except the Laplanders and the rest of the Finnish race, the western Asiatics as far as the Caspian and the Ganges,