ON LIGHT IN SOxME OF ITS RELATIONS TO 

 DISEASE. 



By George T. Stevens, M.D. 



[An address read before the Albany Institute, Dec. 19, 1876.] 



So important, so indispensable, in fact, is the agency of 

 light to life that Lavoisier was warranted in the assertion 

 that, " without light, nature were without life and soul ; 

 and a beneficent God, in spreading light over creation, 

 strewed the surface of the earth with organization, with 

 sensation, and with thought." 



To speak of such an agency in relation to disease as 

 cause and efiect may appear paradoxical, especially when 

 we remember that, in the recent great advances in sanitary 

 subjects, in few if in any other directions have the eftbrts of 

 the sanitarian been so well rewarded as in letting light into 

 dark places. Like the perturbed spirits which of old were 

 supposed to be doomed to walk the night, but which 

 vanished at the approach of dawn, disease and death have 

 often fled before a beam of light which modern science 

 has admitted into some dark corner. 



It is said that soldiers quartered on the sunny side of a 

 barrack possess great advantages in point of immunity from 

 disease over their comrades who occupy the shady side; 

 and experience in large hospitals seems to justify the con- 

 clusion that patients confined by lingering and debilitating 

 diseases do best in the wards most exposed to the sunlight. 



If light, then, is essential to life, is a destroyer of ferments 

 and contagions, and is conducive to the recovery of the 

 sick, how can it be regarded as a cause of disease? We 

 may in a general way reply that any agent which is power- 

 ful for good is also potent for evil — that there is no light 



Trans, ix."] 20 



