CHAPTER XIV 



THE COLOURS OF MAMMALS AND THE ORIGIN 

 OF PIGMENTS 



Coloration of Mammals — Pigments of Mammals — Colour of 

 the Hair and Skin in Man, and its Bearing on General 

 Problems — Origin of Melanin — Pigment and Waste 

 Products — Experimental Evidence — Conclusions — Criti- 

 cism of these Conclusions. 



We have already remarked on the famiHar fact that 

 mammals are rarely remarkable for brilliant pig- 

 ments, the prevailing colouring -matters being the 

 dull-coloured melanins. The statement is, of course, 

 true only of the colours of the skin, for bright pig- 

 ments do occur in the tissues ; thus haemoglobin 

 colours not only the blood but most of the muscles, 

 and yellow lipochromes occur often in quantity in 

 the fat, in the plasma of the blood, in the muscles, 

 and so on. Of these the haemoglobin of the blood 

 is an important factor in coloration in the white 

 races of mankind, and when associated with certain 

 peculiarities of the structure of the epidermis, gives 

 rise to the bright tints of the callosities of many 

 monkeys, of the face of the mandrill {Cynocephalus 

 maimon), and so on. Under normal conditions 



