Manufacturer and Builder 3, 1890
Does this infirmity exist to any notable degree, or is it comparatively rare? Are the sexes affected in equal proportions? Can you tell use if any of the railroads have made it a rule to examine those engaged on their roads?
— J. McL., Denver, Colo.
Answer. Defective color sense, though not to the degree of constituting complete color blindness, is a very common infirmity. To a degree that renders the affected person unable to distinguish colors (red or green, or both) with sufficient distinctness to fit him to act as an engine driver, the infirmity exists in 1 male person in 25, and in 1 female in 2,500. These data have been established by the careful compilation of observations on many thousands of individuals. It will therefore be noticed that males constitute by far the greater proportion of those who are thus deficient. Indeed, a distinguished specialist in this branch; lately stated in our hearing, that though he had examined many thousand individuals, and among them many females, he had never yet found a colorblind woman or girl. We can speak from knowledge of two railway companies only — the Pennsylvania and the Philadelphia A Reading — in reference to the last part of this inquiry. Both of these companies, which together own, or operate, about 12.000 to 15,000 miles of road between them, require all their employes to undergo a careful physical examination; which includes a scientific test of color blindness among its requirements; and no man can obtain employment on either of these roads, in any capacity, where his duties would require him to distinguish the color signals used in connection with train service, who failed to pass a satisfactory examination as to his correct color sensibility. The other great railway companies of the country doubtless also have in use sonic system similar to that in force on those we have specified, for, as the defect is now known to be a very common one, and one which, if ignored, would be certain to give rise to frequent accidents by the mistaking of signals, no railway company would be so reckless as to ignore, the reasonable precaution of an examination of its train hands.
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