12H PROCKKDIWS OK THK ANATOMICAL AND ANTH KOI'i H.OtiK'AI, 



percentage of students with best vision i.e., better than "than 

 those with smaller pupils. 



CoLOl'K OK lltls. 



This was determined by means of Dalton's eyes ; the dark irides 

 include the brown and ha/el eyes, the medium the grey and the green 

 eyes, and the light the blue eyes of other classifications. 



Colour of Iris. 

 Dark 

 Medium 

 Light - 



In the above table dark and light eyes are about equally numerous, 

 the number of medium-coloured eyes being about double either of 

 them. Dark and light eyes are less common among the females than 

 among the males. 



The following table shows the relation of the size of the pupil to 

 the colour of the iris, giving the average size of -the- pupil in the dark, 

 medium and light eyes. 



In Males. In Females. 



Dark - 6'3 G 



Medium G'29 G 



Light - 6-4 5-8 



In the male group, which is by far the larger, a light iris has a 

 slightly larger pupil than a dark or medium iris. Swan/.y, 1 however, 

 states that persons with blue irides have in general smaller pupils 

 than those with dark eyes, for in them more light reaches the retina, 

 and hence the pupil reflex is stronger. 



The following table shows the relation of the acuteness of vision 

 (without correction of refractive errors) to the colour of the iris. 

 The students are divided, according to the colour of iris, into three 

 groups which are each subdivided into three according to the acute- 

 ness of vision. 



1 Handbook of Diseases of the Eye, p. 283. 



