72 INFLUENCE OF LIGHT. 



The salutary influence of the solar light as & 

 stimulus to the skin has been much overlooked, and 

 yet it must be obvious to every one after a moment's 

 reflection. Those who live in mines or dark caves, 

 and who are rarely exposed to the light of day, pre- 

 sent a pale relaxed sallowness of skin, which con- 

 trasts with the ruddy freshness of country people 

 and others living much in the open air. The In- 

 habitants of towns may be known by the light 

 colour and delicacy of skin which confinement 

 induces. Part of the effect is owing, no doubt, to 

 the agency of the external air, in the constitution 

 of which the skin seems to produce changes analo- 

 gous to those which take place in the lungs during 

 respiration ; but much is also attributable to depri- 

 vation of the stimulus of light. Even vegetables 

 become pale, watery, and feeble in the dark; and, in 

 like manner, men who work during the night and 

 sleep during the day never present the vigorous 

 look of health, which distinguishes well-fed day- 

 labourers. The squalid paleness and depression of 

 the poor population, resident in the dark lanes of 

 large and crowded cities, show the necessity of 

 consulting the wants of nature more than is gene- 

 rally done, when erecting new streets and manufac- 

 tories, and providing play-ground for the young. 



When the saline and animal elements left by the 

 perspiration are not duly removed by washing or 

 bathing, they at last obstruct the pores and irritate 

 the skin. And it is apparently for this reason that, 

 in the eastern and warmer countries, where perspi- 

 ration is very copious, ablution and bathing have 

 assumed the rank and importance of religious ob- 

 servances. Those who are in the habit of using 

 the flesh-brush daily are at first surprised at the 

 quantity of white dry scurf which it brings off; and 

 those who take a warm bath for half an hour at long 

 intervals cannot fail to have noticed the great 

 amount of impurities which it removed, and the 



