1840.] 



On the Skin in the Dark Races of Mankind. 



175 



nana Gouda, whose hair and beard are blanched by age, paid me a visit 

 at the mine. He informed me that it is upwards of forty years ago 

 since he dug it ; and that, until Mr Heath's discovery, about twenty-two 

 years ago, he had not the slightest idea of the treasures contained in his 

 own well, and of which he had been robbed for eighteen years by the 

 people he employed. 



In India, the beryl appears to be almost confined to this particular 

 distiict. The natives, however, inform me that it occurs at Vaniam- 

 badi, at the northern base of the Nilgherries, in rocks of a similar age 

 and petrographical character. In Europe it occurs also in the primitive 

 rocks — in the granite and gneiss formations. — Edinburgh New PhilosO' 

 pMcal Journal^ October January 1841. 



XI. — On the Fiinciio?is of the Colouring Matter of the Skin in the 

 Dark Races of Mankind. — By Robert Mortimer Gjlover, M. 

 D., Lecturer on Chemistry in the Newcastle-on-Tyne School of 

 Medicine. 



Various hints and hypotheses have been put forth as to the functions 

 performed by the peculiar organization of the skin in the dark races of 

 mankind. The opinions of Sir Everard Home, published in the 

 Philosophical Transactions for 1821, have been generally adopted by 

 physiologists as apparently founded on a methodical attempt to investigate 

 the subject by direct experiment, and to elucidate it by analogical 

 reasoning. The experiments of Sir Everard give results certainly quite 

 opposed to what has been determined by physical observers respecting 

 the laws which affect the radiation from, and absorption of, heat by 

 coloured surfaces. This circumstance drew my attention to the subject, 

 and led me to repeat some of the experiments related by Sir Everard. 



It may be mentioned, before entering on the subject, that this inquiry 

 was proposed by Lord Bacon. 



The structure of the skin and of its layers is yet involved in some 

 doubt as to many particulars ; but so far as our inquiry is concerned 

 there is no doubt whatever. It is clear that there is a spongy or vascular 

 layer between the cuticle and true skin ; or on the surface of the latter, 

 constituting a portion of it. It is also certain that the colouring matter 

 of the skin resides in this region. And that the intensity of shade is the 

 greater or less abundance of the colouring mutter. Hence the European 



