EARLY HISTORY OF MANKIND. 227 



manently the imperfect brain, projecting lower jaw, and 

 slender bent limbs, of a Caucasian child, some considerable 

 time before the period of its birth. The aboriginal American 

 represents the same child nearer birth. The Mongolian is an 

 arrested infant newly born. And so forth. All this is as 

 respects form ; ( 93 ) but whence colour ? This might be sup- 

 posed to have depended on climatal agencies only ; but it has 

 been shown by overpowering evidence to be independent of 

 these. In further considering the matter, we are met by 

 the very remarkable fact that colour is deepest in the least 

 perfectly developed type, next in the Malay, next in the 

 American, next in the Mongolian, the very order in which 

 the degrees of development are ranged. May not colour, 

 then, depend upon development also ? We do not, indeed, 

 see that a Caucasian foetus at the stage which the African 

 represents is black ; neither is a Caucasian child yellow, like 

 the Mongolian. But the case of a Caucasian foetus, or 

 child, at any of its stages of development, is different from 

 that of a being whose mature form only comes up to the 

 same point. When a being is presented, who at full time has 

 only attained a point of formation such as the Caucasian 

 passed at a comparatively early stage of this embryotic 

 history, there may be a character of skin liable to a certain 

 tinting on being exposed. Development being arrested at so 

 immature a stage in the case of the Xegro, the skin may 

 take on the colour as an unavoidable consequence of its 

 imperfect organization. It is favourable to this view, that 

 Negro infants are not deeply black at first, but only acquire 

 the full colour after exposure for some time to the atmo- 

 sphere ; also that the parts of the body concealed by clothing 

 are not generally of so deep a hue as the face and hands. 

 The phenomenon, in short, appears identical in character 

 with the photographic process ; not a result of the action of 

 heat, as has been so long blunderingly supposed, but of light ! 

 It takes its place under the infant science of actino-chemistry, 

 to which, perhaps, many other remarkable phenomena con- 

 nected with the natural history of our race will yet be 

 referred. This view, seeming to account for all the varieties 

 Q2 



