EYES THAT SHINE AT NIGHT — WALKER 351 



off by the eyes of alligators, crocodiles, and caimans; "shining" their 

 eyes gives one the impression that he is looking into a brilliantly 

 glowing pinkish opening in a dull surfaced bed of coal. In the 

 majority of mammalian eyes observed I have gained the impression 

 of looking at a highly polished metal surface. Sometimes the effect 

 is likened to looking into an incandescent globe of the color indicated. 

 Often pronounced light rays appear to emanate from the eyes. In 

 some eyes, such as those of the smaller rodents, the effect is that of 

 looking into an illuminated piece of amber. 



To assist the reader to understand the character of the reflections, 

 a colored drawing has been prepared for a few animals, to show some 

 of the range of reflections obtained. Efforts were made to produce 

 a plate that would show not only the colors but the glow or brilliance 

 of the eyes, but several artists were unable to produce the effect even 

 on an original and, had they done so, it is doubtful whether it could 

 have been reproduced. The proper effect could undoubtedly be well 

 simulated by placing small incandescent lights behind translucent 

 spots of the right color on an opaque background. Indeed, the 

 brilliance of the reflections is as impossible to show as is the gleam 

 from snow in sunlight. At my suggestion, Mr. Fred Adams of the 

 Dufaycolor, Inc., New York City, experimented in taking a few color 

 pictures by photoflash. The results as to eye shine, though not 

 entirely satisfactory, are promising. 



The illustration shows the eyes in pairs, and as disks. Frequently, 

 however, only a single eye is seen, or in some instances, depending 

 on the position, both eyes are seen as ovals or crescents, or other 

 modifications of a true circle. In practically all species, however, it 

 is possible to obtain the shine in both eyes simultaneously to some 

 extent, even though they are not perfect circles. 



A confusing factor is the circumstance that different persons 

 apparently see the reflections as quite different colors. One person 

 who is usually good in recognizing colors by daylight insists that the 

 reflections are without color. Others have described or painted for 

 me their conception of some of the reflections much more reddish 

 than I see them. 



I have made no experiment designed to prove which surface of 

 the eye produces the reflections. In the case of the animals that 

 have eyes that "glow" or are like amber it appears that we look into 

 the eye through the pupil as if the reflection came from the front 

 surface of the retina. In those animals that give a reflection as from 

 polished metal I gain no impression of looking into the eye. In most 

 of these cases, however, the reflection is not obtainable closer than 

 8 to 20 feet — a distance that prevents one from observing which 

 surface reflects. The reflections of alligators, crocodiles, and caimans 

 can be seen when the observer is within a foot of the animal. In 



