Licence: Public Domain Mark
Credit: Color-blindness : remarks / by B. Joy Jeffries. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![stated most freely that be would be most dangerous ou the watch, all the more, as he would sometimes be right. Such a man would be sure to escape detection except by thorough tests in competent hands. The completely defective generally give it up, or rely ou some one else ; the partially color-blind, being often right, are only too firmly convinced that they always are, and readily deceive those about them into the idea that at the most they are only a little careless or inattentive, lied and green lights, close by, they distinguish; but at a distance, when the normal eye easily and instantaneouslv recognizes them, the color is gone, or becomes doubtful; hence, the peculiar danger. The truth is, that, both on the railroads and on the ocean, each and every degree of chromatic defect is dangerous to life and property, and I might almost say, in inverse ratio to the amount, because the lesser degrees readily escape detection, and go on with the official stamp or sanction of their harmlessness. Experience on the railroads has proved this most conclusively. I believe the time will come when the commu- nity will demand absolute freedom from color-blindness in railroad employes and mariners. The local inspectors or any of the laity, if they attempted to test by the signal-lights even those who were found by the surgeons completely color-blind, would, perhaps, equally ofteu come to the conclusion that such were not defective or dangerous, and be perfectly willing to re- license them, even without the pressure spoken of in the reports of the surgeons of the department. Still more likely would they be to assure themselves that the partially color-blind were either not so, or if so, scientifically, as is often said with a sneer, yet perfectly safe and trust- worthy as pilots. Now, then, partially defective men, who either see signal-lights when near enough, and when in a room guess at them almost always correctly, are precisely those who are dangerous; and local inspectors testing them with signal-lights, and giving their official sanction to the license, only renders them more dangerous, since then their employers are confirmed in the belief of their freedom from defect of any kind. A competent medical examiner will with certainty very quickly detect any degree of color-blindness by Holmgren’s worsted test, and he can equally well show, by proper apparatus, that such blindness is danger- ous. Testing with signal-lights will not show this danger, and this is the special reason why I appear at this time before this board. Nothing seems more self-evident than that the way to find out a man’s color sense and his capacity for reading colored signals is to put up the signal-lights and ask him what he sees. Upon this very naturally is based the Circular No. 4G, allowing local inspectors to test with signal- lights. The same mistake has been made by other boards, and without the good excuse this board has, that it was acting to the best of its knowledge and ability in yielding, to the pressure to retain partially] defective pilots. It could not accept unchallenged the assertion and opinions of the Medical department in the face of such seemingly common-sense ideas, that to take a pilot out and ask him the names of the passing colored lights, or to hold up signal-lights a short distance oft and do the same, was not the truest, fairest, and readiest way of finding out his color perception. I am here, as I said, to disprove this, which is thoroughly discussed and shown in my Manual. It I do not succeed in convincing this board it will be simply from my lack of properly presenting the subject.](https://iiif.wellcomecollection.org/image/b22370110_0022.jp2/full/800%2C/0/default.jpg)
