652 THE POPULAR SCIENCE MONTHLY. 



Crude, simple, and at first sight ludicrous as it may appear, it is 

 nevertheless worthy of consideration that the negro is black, and, in 

 the absence of moonlight or artificial illumination, can not at night be 

 so readily seen as a white man ; he may therefore on this account escape 

 the sight, and consequently the bite, of the mosquito. The deep tint 

 of his skin possibly constitutes a "protective coloring,'''' such as in 

 many other species affords a defense against natural enemies. More- 

 over, the habit, common with many negro races in their native heath, 

 of daily anointing the body with grease, affords additional protection 

 against mosquitoes, as do also, probably, the offensive odor and greasi- 

 ness of his cutaneous secretions. In this connection the work of Dr. 

 Balfour on " Sol-Lunar Influence " in malarial fevers, hitherto ignored, 

 deserves reconsideration. The light of a full moon would render the 

 negro more visible to his culicidal enemy. 



When the negro is imported into this country, and subjected to the 

 conditions of civilized life which usually comprise, among the rest, 

 his remaining during a part of the evening in rooms artificially illumi- 

 nated, or sleeping with his black body portrayed in bold relief upon 

 white bedclotbing the mosquital blood-suckers will then have little 

 difficulty in finding their victim, notwithstanding his protective mela- 

 notic mantle. 



The Conservative Function of Ague. In my original paper, 

 read before the Philosophical Society of Washington, on the 10th of 

 February last (and of which, as I have said, the present production is 

 an abstract), I suggested that the natural conservative design of the 

 processes embodied in the term ague was to develop malarial melano- 

 sis in fact, to change the skin from white to black, thus securing adap- 

 tation to (i. e., protection against) the environment of inoculating gnats, 

 by clothing the individual with a cutaneous mantle of " protective 

 coloring." The spleen I therefore regarded as the organ, one of whose 

 offices is, as it were, to preside over and determine the cutaneous col- 

 oring of the individual a function not hitherto ascribed to it ; though 

 its pigment-forming function, by destruction of blood-corpuscles in its 

 substance, has been long known. The absolute transformation from 

 white to black under the influence of malarial disease has been fre- 

 quently observed (see a case by Dr. William II. Falls, in the " Cincin- 

 nati Lancet and Observer," November 18, 1882, pp. 479-488). Sur- 

 geon-General C. A. Gordon, in his account of the fever among the 

 British troops in Cyprus (" London Medical Press and Circular," new 

 series, vol. xxx, p. 303), in 1878, says : " The Forty-second Regiment 

 suffered terribly at Cyprus ; the men looked worse than they did on 

 the Gold Coast pale and sallow, or Hack (italics Ids), the pure malarial 

 melanosis." 



Be it noted, further, that the causes or conditions that lead to 

 different tints of color in different races of men since it is now known 

 not to depend, as once supposed, upon heat of climate is a complete 



