734 VERHOEFF AND BELL. 



of the magnetite arc here in question while yet remaining within 

 perfectly safe limits from any practical standpoint. No actual arti- 

 ficial illuminant can fairly be considered dangerous from the standpoint 

 of thermic action on the retina. It will be observed that since no 

 screens were used, these experiments also afford evidence of the harm- 

 lessness of abiotic radiations to the retina. 



Glassblowers' Cataract. 



The fact that glassblowers are subject to a special form of cataract 

 has naturally raised the question whether or not the latter is due 

 to radiant energy and if so, whether to abiotic or thermic action. 

 Meyhofer ^*^ examined 506 glassmakers and found 11.6% affected with 

 cataract. The cataract almost always appears first in the left eye 

 which is the more exposed to the light. When it appears first in the 

 right eye it has been found that the glassblower has been in the 

 habit of turning this eye towards the oven (Stein ^*^) . The glassblow- 

 ers show also a peculiar rusty brown spot on each cheek, more marked 

 on the left. The length of time necessary for the development of the 

 cataract has not been exactly ascertained, but it is evidently several 

 years. The cataract usually begins before the age of 40. In Mey- 

 hofer's series the youngest blower was aged 15 years and the youngest 

 affected with cataract 17 years. Of 59 cases of cataract, 42 were under 

 the age of 40. In the latter cases, both eyes were affected in 16, the 

 left eye alone in 19, and the right eye alone in 7. The glassblowers 

 are thin and delicate, and are subject to asthma and pulmonary tuber- 

 culosis. Almost all of them have emphysema of the parotid gland. 

 During their working hours they perspire excessively and in conse- 

 quence drink enormous quantities of fluids, including beer, coffee, 

 wine, and lemonade. 



The cataract begins as a rosette like or diffuse opacity in the cortex 

 at the posterior pole of the lens, the remainder of the lens for a long 

 time remaining clear. Later, striae similar to those of senile cataract 

 may appear. At operation the nucleus is found larger than that of 

 other individuals of the same age (Stein ^*^), and the capsule more 

 fragile (Cramer ^^). Parsons ^^^ states that in only one-fifth of the 

 cases does the cataract differ in appearance from a senile cataract, 

 but this probably applies to the late stages. 



Hirschberg ^^^ states that for over 100 years it has been recognized 

 by various observers that individuals exposed to intense heat and light 



