The Effects of Ultra- Violet Rays upon the Eye. 



319 



membranse proprise the veins are so far narrowed as to raise the pressure in 

 the capillaries and veins ; this, coupled with the dilatation of the arteries, 

 gives a greatly increased rate of blood flow. The circulatory conditions 

 which pertain in these encapsulated glands resemble those which pertain 

 in the brain and the skull cavity. 



The Effects of Ultra-violet Rays upon the Eye. 

 (Keport of experiments carried out for the Glassworkers' Cataract Committee 

 of the Eoyal Society.) 

 By Dr. E. K. Maetin. 



(Communicated by Sir J. R. Bradford, Sec. R.S. Received February 5, — 

 Read March 14, 1912.) 



(From the Research Laboratories, University College Hospital Medical School.) 



[Plates 4—7.] 



In 1909 Messrs. J, Herbert Parsons and E. E. Henderson commenced some 

 experiments on the action of short wave-length light on the lens and ciliary 

 body, using Uviol glass mercury-vapour tubes and examining the lens and 

 its capsule after exposure. To test for damage to the ciliary body too slight 

 to be appreciable microscopically use was made of an observation of Romer's, 

 that in animals sensitised to the blood of another species, haemolysins were 

 not transmitted from the blood to the aqueous unless the constitution of the 

 latter were altered by a previous paracentesis or an inflammatory lesion of 

 the iris and ciliary body. Positive results were obtained, but the experiments 

 were not sufficiently extensive to be conclusive. I have, therefore, on behalf 

 of the Committee of the Royal Society on Glassworkers' Cataract, repeated 

 and extended the experiments along lines suggested by Mr. Parsons. 



In the attempt to determine the effect of rays of various wave-lengths on 

 the media of the eye, attention has been paid to three possible setiological 

 factors: — (1) The intensity of the light. (2) The part of the spectrum 

 mainly represented in the source of light. (3) The possibility of the inclusion 

 of electrolytic and mechanical as well as of radiant energy. 



1. Intensity. — It has been customary among investigators of the subject to 

 express the intensity roughly by naming the source of light, the quantity of 

 energy (usually electrical) consumed in its production, and the distance of 



