636 VERHOEFF AND BELL. 



This effect of the electric light is very curious and in its pathology one may 

 perhaps find the rationale of sunburn properly so-called. Everybody knows a 

 high temperature is not a necessary condition for the production of this last 

 affection, for there are some people who are attacked in the cool weather of the 

 first days of spring, a fact analogous to those which we here report. Both 

 concur in showing that in the radiation of the light it is not the calorific rays 

 which attack the skin. 



Must one then invoke the action of the luminous rays themselves? No, or 

 at least the intensity of the light seems to play only a secondary role. Indeed 

 in the experiments made by M. Foucault in coupling several Ruhmkorff coils 

 to produce sparks of which the length increased with the number of bobbins 

 and where he had been able by the means of a double action interrupter to 

 double the number of these sparks without diminishing their energy, this 

 observer was attacked by headache, very marked and persistent troubles of 

 vision and erythema, although the light was not more intense than that of a 

 star which one looks at without fatigue. M. Despretz has noted that light 

 obtained with 100 Bunsen elements produces eyeache and that from 600 ele- 

 ments very rapidly produces erythema. 



There remain the so-called chemical rays and it is this sort of rays which 

 seems to be the principle essential agent of the accidents. To protect the eyes, 

 it suffices as M. Foucault has several times noted, to let the electric light pass 

 through a uranium glass screen which absorbs a large proportion of the chemi- 

 cal raj^s. Doubtless by protecting the face with this same uranium glass one 

 would avoid also the production of erythema. The very rapid and energetic 

 action of the electric light upon the skin and upon the retina one can under- 

 stand the better since the chemical rays in it are as is well known relatively 

 more abundant than in the solar light. 



An ordinary clinical case of photophthalmia as observed after 

 exposure to arc lights, short circuits, and the like, commonly takes 

 the following course. After a period of latency, varying somewhat 

 inversely with the severity of the exposure, but usually several hours, 

 conjunctivitis sets in accompanied by erythema of the surrounding 

 skin of the face and eyelid. There is the sensation of foreign body 

 irritation, more or less photophobia, lacrimation, and the other ordi- 

 nary symptoms of slight conjunctivitis. Occasionally there is some 

 chemosis. The symptoms usually pass off in two or three days, and in 

 severe cases there may be desquamation of the affected epidermis 

 around the eye. In a very few instances the cornea has been slightly 

 and temporarily affected. There is almost always immediately fol- 

 lowing the exposure, and quite unconnected with the photophthalmia 

 proper, the ordinary results of a glare of light in the eyes, persistent 

 after images, occasional scotomata, erythropsia and xanthopsia. 



