LIVING LAMPS 



241 



rarely ranging from the red to violet, and shows no lines. As 

 light it is very nearly perfect, with practically no non-visible 

 emanations. 



Before we leave the subject of animal light we must notice 

 briefly the glowing of the eyes of cats and similar phenomena. 



This is not due to any light originating in the eyes them- 

 selves, but to reflected light from a source behind or in front 

 of the observer and near his line of vision, and it varies in in- 

 tensity with the light reflected. Thus in the bright light from 

 automobile headlights the eyes of dogs and cats, rabbits and 

 deer, often shine like electric lights themselves. 



Generally speaking mammals' eyes shine brightly blue or 

 green, more rarely white. Perhaps the brightest are those of 

 wolves, coyotes and some dogs, which shine a dazzhng white, 

 and of hyaenas, w^hich show a tinge of red. An automobile 

 headlight will sometimes pick them up a quarter of a mile or 

 more away, gleaming like little electric lights. With a dimmer 

 light, as of an oil lamp, most dogs' eyes shine greenish. 



Everyone has seen cats' eyes shine green. Wild cats' eyes 

 shine the same but are much brighter, like the large eyes of 

 the lemurs. Lions' and tigers' eyes shine also green, but are 

 not so bright as wild cats'. 



Opossums' eyes are very bright, white, almost like little 

 electric lights. The eyes of rabbits and of deer shine blue or 

 bluish white; horses' and cattle's eyes are similar, but duUer. 



In contrast to the eyes of other mammals our eyes shine a 

 dull red, like the eyes of crocodiles and birds. Small children's 

 eyes are usually quite bright, and the red reflection is easily 

 observed if you place them in the dark with a light coming 

 from behind you. Boys' eyes soon cease to shine. The eyes of 

 girls usually shine longer, and sometimes women's eyes shine 

 almost all their lives. 



Very few birds' eyes will shine at all. But the goatsuckers, 

 including our whip-poor-will and chuck-will's-widow, have eyes 

 that gleam a vivid rub>- red and are conspicuous for a long dis- 

 tance. Mr. H. S. Barber and Dr. Alexander Wetmore have 



