The Tropics and Pigment. 363 



'Of disease, my own experience of the tropics has shown me that 

 the white man in the black man's country degenerates mentally, 

 physically, and morally, and that his children are attenuated 

 specimens of his race. Thus I am compelled to affirm that 

 labourers will ever need the protection of colour in direct rela- 

 tion to their environment. 



The Complex Nature of Animal Pigments. 



. As our subject was extended to include all living organisms, 

 -some reference must be made to the complex nature of their 

 pigmentation. To understand the reason of the diversity of 

 colour that appears in animals, it is necessary to look into the 

 conditions that give rise to the need of colour, and they may be 

 best presented by the following homely illustration : — 



A man may put on any old coat to protect himself from the 

 sun's rays, but a soldier needs the security of colour, and wears 

 khaki. To distinguish the officer, he is adorned with gold braid 

 and buttons, a most powerful weapon in the struggle for sexual 

 selection. So it is with animals. Any old coat seems to serve 

 our domestic companions, whilst animals that live in peril of 

 their lives are warily clothed ; and others, who are free from 

 that anxiety, are adorned for the struggle of sexual selection. 



Behind these post hoc performances there is some subtle agent 

 at w^ork, the biological factor, life. A man's circumstances may 

 demand a coat, but these circumstances do not make the coat, 

 and so it is with Nature's " visible garments." Btit the coat is 

 constructed out of matter and force, and so one must conclude 

 that the factors that are concerned in the production of pigment 

 are^ — life, matter and force. In declaring an adherence to this 

 three-fold division, one is privileged in. that much of the dogma 

 that has been founded on hypothetical science is in a state of 

 flux. But life, matter and force exist, and in distinguishing the 

 vital from the physical I will here simply assert my cTkim as an 

 article of faith. 



The influence of breeding on colour determines the importance 

 of the biological factor, which shows its highest effort in sexual 

 selection. It is not required to give evidence that matter, as a 

 change of food, and force, as a change of environment, will also 



12a 



