1840.] 



On the Skin in the Dark Races of Manhhid. 



177 



may be apparent that, since Sir Everard published, the matter has been 

 misunderstood. 



The notions entertained at present by physiologists, with regard to the 

 operation of this pigment, are implicitly those ol" Sir Everard. And what 

 they are, will appear from the following brief quotation from an elemen- 

 tary work :—" The secretion on the cutis vera, which gives the black 

 colour to the skin, appears to assist in fitting men for residence in hot 

 climates, because although such skin, by absorbing more caloric, rises to 

 a higher temperature under the sun's rays than white skin does, yet it 

 does not inflame so readily from a rise of temperature." Dr. Alison's 

 meaning is, that although the skin of a negro may rise to a higher tem- 

 perature under the sun's rays than a white skin in the same circum.stances, 

 yet the dark skin is less likely to inflame at that highe?- tempei-ature than 

 the white skin at that loiver one. This, then, is the conclusion of Sir 

 Everard Home, whose paper I now proceed to examine. 



The paper of Sir Everard Home contains alleged facts and experi- 

 ments, tending to prove the Negro more capable of witlistanding exces- 

 sive heat of the sun's rays than the white man, and attributing this to a 

 supposed property in dark surfaces of destroying the scorching and blis- 

 tering effect of tlie sun's rays. The former conclusion has already been 

 admitted. The facts by which Sir Everard supports his second position 

 are to be considered. 



Sir Everard having fallen asleep on the deck of a vessel exposed to a 

 tropical sun, found, on awaking, his thigh scorched through a pair of thin 

 white linen trousers. From this simple observation, the extravagant 

 conclusion is drawn of black being a better protection against the sun's 

 rays than white. 



An experiment is next related, in which Sir Everard found, on expos- 

 ing his hand to the sun's rays for 4-o minutes, while a thermometer at- 

 tached to it stood at 90*^, that blisters rose and coagulated lymph was 

 exuded. I have attempted to produce the same effect by the concen- 

 trated rays of the sun at the same temperature indicated in a similar wa}', 

 and kept up to within one or two minutes of the time, when my patience 

 was exhausted, without any result except slight reddening. Six years 

 ago, while off the coast of Algiers, I sat for half an hour immoveable in 

 the sun, having the greater part of my face exposed, the thermometer in 

 the sun's rays being considerably above 100°, and though my face was 

 scorched, nothing like the effect described by Sir Everard took place. 



Sir Everard next attempted to compare the inflaming and blistering 

 power of the sun's rays with that of hot w'aler. He says, that water at 

 the temperature of 120" was painful to the body, and became unbearable 



