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 familiar 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 
