P^BBUARY 1, 1899.] 



KNOWLEDGE. 



27 



vera shines through the semi-transparent layers, and 

 any change in the vascularity of the cutaneous surface of 

 the body is at once apparent, whether it be brought about 

 by external or internal stimuli. The bronzing of parts of 

 the body, due to exposure or to the influence of sunlight, 

 is probably the consequence of the increased cutaneous 

 blood supply bringing more of the red, brown, and yellow 

 pigments to the deeper cells of the irtt' mucosum. Freckles, 

 which, curiously enough, occur most frequently on those 

 with hair of a pronounced red colour, do not dififer in any 

 respect from the pigmented skins of the darker races, except 

 in regard to their colour and their circumscribed appear- 

 ance. In persons of dark complexion there is, in addition 

 to the red, brown, and yellow pigments, probably a very 

 slight admixture of the black pigment. This may be 

 present in sufficient quantity to impart a blackness to the 

 hair, but not abundant enough to destroy the fairness of 

 the skin, though in exceptional situations its presence 

 may be very evident. 



By gradual transitions we may pass to those races in 

 which the cutaneous pigment is present in sufficient quan- 

 tity to mask the colour of the underlying tissue and impart 

 thereby a sallowness to the complexion. These are the 

 yellow races, and if sections of their skin be studied they 

 will be found to differ from the highly pigmented cuticle of 

 the negro only in the depth of the tint of the pigment con- 

 tained in their deeper cells. By further steps we can pass 





^. 



i<^. 



.turn corneum. 



'ifinu iiiucosfofi. 



neut in deeper cell: 

 ^tt'atum iHitcosum. 



Fig. 3. — Photomicrograph of Section through Negro's Skin, 

 showing distribution of Pigment. 



easily from the yellow through browns of various sorts to 

 the absolutely black races. Here the pigment is present 

 in varying quantity, in some skins only the deepest row 

 of the cells of the mucosum is loaded with the granules, 

 in others the mucosum for several cells deep may contain the 

 pigment, but it ceases to colour the cells before the stmtum 

 ;li;inulosum is reached. Thus, one skin, to all intents and 

 purposes as black as another, may contain a much less 

 amount of pigment, just as we have seen in the case of 

 hair. 



At present our method of classifying the colours met 

 with in man is crude and not very trustworthy. The best 

 means at our disposal is to employ the colour tables pub- 

 lished either by the Anthropological Society of Paris or 

 the Anthropological Institute of London. But even this 

 is admitted to be far from satisfactory. The difference in 

 the texture of the things compared causes a difficulty in 



the matching of the tints. For our part we think a much 

 better plan would be the employment of carefully dyed 

 pieces of kid, such as are used in the manufacture of 

 gloves ; these could be laid over the skin to be matched, 

 and a much more reliable result obtained. Unfortunately, 

 there would be some difficulty in standardizing the colours, 

 but with some trouble this might be effected. Further, 

 care must be taken to sample the colour of the skin on 

 different parts of the body, for the more exposed parts are 

 naturally those which display the darkest tint. In using 

 either the English or French standard colour sheets, 

 observers have found, as a matter of experience, that it is 

 better to cut a hole in a piece of paper corresponding in 

 colour with that on which the standard tints are printed, 

 and then placing this on the skin to be examined, compare 

 the patch exposed through the hole in the paper with the 

 standard tints held side by side. 



But a mere enumeration of standard tints does not assist 

 us very much. In all cases it seems to us advisable that 

 a lock of hair should, if possible, be obtained from the 

 individual examined. As we have already hinted, we 

 consider the hair a more important index of colour than 

 the skin itself, because by taking given weights of hair, 

 and extracting the pigments from it, we would be in a far 

 better po3ition to determine with accuracy the relative 

 proportions of pigment present. It is assumed, of course, 

 that the hair taken had not been subjected to the in- 

 fluence of lime or other "dressings," and that 

 there was no evidence of senile change in the hair. 

 No doubt the research would be arduous, but the 

 results would amply repay the expenditure of time 

 and trouble. 



But, in addition, there are many other details which 

 seem to have a more or less direct influence on colour 

 production. Of these, temperature may be men- 

 tioned, diurnal as well as nocturnal. The moisture 

 of the atmosphere. The nature of the soil. The 

 diet. The manner of life, whether dwellers in dense 

 forest or jungle — where, for example, the natives 

 are screened from the sun's rays — or dwellers on the 

 hUls and plains, where they are most exposed to 

 light and alternations of temperature. On the other 

 hand, much information is wanted with regard to 

 their susceptibility and immunity to disease of 

 certain kinds. Apart from the ansemia consequent 

 on the disease, whites, who suffer from malaria, 

 appear to acquire a darker complexion. As has been 

 hinted by Darwin, it is just possible that dark- 

 ness of the skin may have been evolved, and is in 

 some way connected with the immunity which coloured 

 races possess from such diseases. There seems to be 

 evidence, too, that in the dark races the size and 

 consequently the weight of the liver is proportionately 

 greater than in the white races. Unfortunately such data 

 are not easy to obtain, but they would be of much service 

 in enabling us to criticise certain theories that have been 

 propounded. Certain it is that whites in tropical climates 

 are much more liable to derangements of that organ than 

 is the case with natives. Another line of enquiry which 

 might much help us to solve the problems of the mode of 

 production of this pigment, and the regeneration of the 

 epidermic layers, would be a careful study of skin diseases 

 in the dark races. We are not aware that it has been 

 approached from this standpoint, but we are confident 

 that it would prove a highly interesting field for re- 

 search. 



The above are a few of the facts which, it seems to us, 

 would help in the elucidation of a problem about which 

 in reality we know very little. 



