THE EYES AND EARS OF EMPLOYEES OF TRANSPORTATION COMPANIES
Journal of the American Medical Association (JAMA)
note the contrast between this and other methods, and between the use of perfectly and imperfectly distilled water, with the conclusion that if instruments were to be sterilized by boiling, the farther one departed from perfect purity of the water, the worse was the result. The addition of soda to ordinary water seems to allow comparatively large instruments of simple con¬ struction to be boiled without injury, but a deposit takes place on the surface which, when involving delicately or
... licately or intricately made instruments, results in more or less damage and is especially hard on cutting edges. I have found sterilization by vapors so unreliable that I will take up no time with the details. Chemical sterilization has also proven very unsatis¬ factory, all aqueous solutions having a tendency to attack the edge of knives. Only one substance, formalin, when used according to the method so admirably worked out by Dr. Lippincott of Pittsburg, has seemed to be efficient. But the process involves prolonged immer¬ sion and practically means keeping one's armamen¬ tarium in the solution, which it would seem might be rather inconvenient, especially with the large equipment of the general surgeon. And for operations within the eye, instruments must be wiped with some sterilized substance before they can be used. Several other chem¬ ical substances were tried, and among them lysol was found to be rather the least objectionable, but in any strength it can not be relied on to sterilize infected instruments in a reasonable time. A knife blade thickly coated with pus from an ordinary phlegmon retained active pyogenic germs after two hours' immersion in the undiluted solution. A similarly infected blade, when wiped clean, became sterile after one hour's im¬ mersion in a 1 per cent, solution, but the edge had be¬ come perceptibly dulled. A control blade, not so dis¬ infected, yielded an active culture in gelatin. Practic¬ ally the only objections to this method were the damage resulting to cutting edges from all aqueous solutions, and the necessity, as in the case of formalin, of wiping instruments for intraocular operations. The absolute reliability of boiling water is so well appreciated that no bactériologie experiments were made in its behalf, the writer confining his attention entirely to the effect produced on cutting edges of instruments. If our ordinary hydrant water was used, the edge of a knife was ruined, and in fact the whole instrument was damaged. The addition of soda to the water pre¬ vented the latter trouble, but only slightly lessened the harmful result to the edges. Rain water, and the con¬ densed vapor of the artificial-ice establishments yielded less disastrous results, but still a knife boiled in these solutions, even with the addition of various preparations of sodium or potassium, was unfit for delicate use. As a consequence, inquiry of a large number of general surgeons elicited the information that, while instru¬ ments in general were usually prepared for operations by boiling, knives were simply scrubbed carefully, or scrubbed and dipped in alcohol. The efficiency of alco¬ hol as a disinfectant has been so frequently questioned that its use seems almost superfluous. In conclusion it was found that not only may instru¬ ments be safely boiled in distilled water a sufficient length of time to become sterile, but also if distilled water is used in a sterilizer that is free from oxidized metal the vapor and steam thus generated can be availed of for the preparation of instruments, dressings and other appurtenances of an operation without harm¬ ful results to any of them, which would seem a conven¬ ience and simplicity greatly to be desired. Color-blindness is an abnormal condition of the visual apparatus, causing an inability to accurately, invariably and properly distinguish the colors of the solar spectrum. Several varieties exist, but the most frequent is that causing difficulty or impossibility in distinguishing between red and green, which is especially unfortunate, as these colors are universally adopted as important signals in transportation service. Investigations indicate the universality of chromatic aberration in all observed nations, but with diminished frequency in the educated, and in peoples possessing great love for colors and artistic decorations such as the Africans, Japanese and Chinese. Indeed, it is claimed by some observers that the people of India are able to perceive 300 different shades of colors not perceptible to European eyes. No evident physical manifestation exists rendering an objective diagnosis possible. Opinions as to color visual acuity must therefore rest on tests, which are well described in text-books. My brother, Dr. W. H. Allport of Chicago, in examinations of over two thousand negro men, failed to find a single case of even incomplete color-blindness. This has been observed by others, so that the observation is well authenticated. Instances are occasionally recorded (Hubert, Woinow, Hasner, Sehröter, Mayerhausen and others) of excessive chromatic sensibility amounting to chromophobia, where the exhibition of specific colors pro¬ duced great fear, pain and other neurotic sensations, probably of cerebral origin. Lussona mentions two students, with aural sensa¬ tions distinctly associated with chromatic conception. High voices produced subjective sensations of red; low voices of black. A bass voice sounded black, a baritone dark brown, etc. Toxic color sensations are noteworthy, as hyoscyamus niger, duboisin and atropin produce red vision, santonin and picric acid, yellow vision, etc. These instances point to cerebral color per¬ ception, and Samelsohn, Landolt and Wilbrand advo¬ cate a separate color cortex, which is, however, denied by 0. Bull, Dahms and others. The term "color-blindness" is misleading, and too comprehensive, and conveys the impression of invari¬ able total chromatic exclusion. I would suggest the terms "color amblyopia" and "color amaurosis;" the first to indicate the frequent conditions of partial loss of chromatic sensibility without apparent lesion, the latter to indicate that rare condition denied by some authors, although vouched for by Querenghi and others, of total loss of color sense without apparent lesion, where all objects appear in black and white, like a crayon or photograph. Color ambylopia or amaurosis is not induced by any chromatic alteration of the ocular media. It is prob¬ ably occasioned by some abnormality of the receiving (retinal) fibers, the conducting (nerve, ehiasm and tract) tissue or the perceiving (cuneus) apparatus.