Evening Republican, Volume 22, Number 171, Rensselaer, Jasper County, 22 July 1919 — How Light Changes Shape of Pupil of Eye of Both Animal and the Human [ARTICLE]

How Light Changes Shape of Pupil of Eye of Both Animal and the Human

Nothing is more deceptive than the appearance of a cat’s eye. The pupil ordinarily appears as a long, narrow oval or a vertical black line, yet its natural shape is.circular. It is a matter of the effect of light In a bright light our pupils become very small circles, while those of a cat turn into ovals or narrow slits. The general effect is the same in either case —namely, to diminish the quantity of light passing Into the eye. Curiously enough, in the larger animals of the cat tribe, such as tigers, the pupil sometimes behaves exactly like a human pupil, and when brightly Illuminated contracts Into a minute circle instead of becoming linear. In the case of domestic cats, the older the annual the more frequently does the pupil of the eye assume a circular form.