: 94 THE POPULAR SCIENCE MONTHLY. 



COLOR-BLINDNESS AMONG EAILKOAD EMPLOYES * 



By WILLIAM THOMSON, M. D., 



PROFESSOR OF OPIITHAL1IOLOGY IN TIIE JEFFERSON MEDICAL COLLEGE OF PHILADELPHIA. 



THE conflict between the officers and the employes of the Reading 

 Railroad, with its forty-two thousand employes on three thousand 

 miles of track, which has occupied recently the attention of the public, 

 and has threatened to produce a suspension of work on that road, has 

 reopened the question of color-blindness among railroad employes, and 

 led to a full demonstration of its existence among those engaged even 

 as engine-men, where the defect might lead to serious accidents, with 

 loss of property and life. The officers of the road have selected the 

 system for examination suggested by the writer, and employed to a 

 full success for more than live years past on the Pennsylvania Rail- 

 road, and have appointed me to supervise its details, and, as ophthal- 

 mological expert, to decide all doubtful cases after careful examina- 

 tion of those found defective by the non-professional examiners of the 

 company. 



The conflict is nearly over, since demonstrations of the optical defect 

 in engineers, made before a committee appointed by the employes have 

 satisfied them of the propriety of the testing, and that the safety of the 

 traveling public demands the removal of all color-blind persons from 

 positions where their optical defect might be the cause of distressing 

 accidents. In the recent demonstrations, I was able at my office to show 

 that an engine-man declared a red danger-signal, made by placing red 

 glass in front of a large gas-light at a distance of two feet away, to be 

 a green light ; he was also not only unable to distinguish a red from a 

 green flag within six feet, but he failed to classify the flags, white, red, 

 green, and blue, properly, even when allowed to take them in his own 

 hands. 



The system adopted by the Reading Railroad is the one in use on 

 the Pennsylvania Railroad, and owes its value to the fact that large 

 bodies of employes can be brought under inspection, and their defects 

 discovered by non -professional examiners. It has been fully described 

 in the "Medical News" of January 14, 1882, in the second edition of 

 Nettleship's work on " Diseases of the Eye," and in a paper read before 

 the American Association for the Advancement of Science, in Septem- 

 ber, 1884, and in " The Popular Science Monthly " for February, 1885, 

 and to those sources the reader is referred for further information. 



Previous to its adoption by the officers and directors of the Penn- 

 sylvania Railroad two thousand men were examined, and their blanks 



* An article on this subject, by Dr. Thomson, was published in the " Monthly " for 

 February, 1885, and, as a continuation of that paper, we give herewith from the " Medical 

 News" an account of the more recent experience of the Pennsylvania Railroad with the 

 system of examinations mentioned, and the results of its application to other lines. Ed. 



