ORGANS OP THE SENSES THE EYE DIAGRAM 2 21 



attention. And on these small ridges we observe rows of points 

 like the holes which might be made by the point of a very fine 

 needle. These are openings, and in warm weather we may 

 observe that there is a very small drop of sweat in each of these 

 holes. It is in reality from these that it flows. 



There are other holes in the skin through which the hairs 

 of the head and beard pass, the roots of which lie deeper. 

 They are very seldom entirely removed when the hair is pulled 

 out, and it nearly always grows again. The hair and beard, 

 if left uncut, do not grow indefinitely, and after reaching a 

 certain length, do not grow longer. The hair in children, as 

 well as in older persons, ought always to be brushed, combed, 

 soaped, and kept very clean. Whatever may be the current 

 ideas on this subject, cleanliness of the heads of children is 

 necessary to their health. 



When we are slightly scalded with too hot water, or apply a 

 blister, a portion of the skin rises, and water collects underneath. 

 This is called a blister. If this skin is cut, we see that it has no 

 feeling, and that no pain is caused. The bottom of the blister, 

 on the contrary, is exceedingly tender, and cannot be touched 

 without causing pain. The raised and insensible portion is 

 called the epidermis, and it is only the outermost part of the skin. 

 By working with the hands, the epidermis thickens, and then 

 becomes horny. The lower part of the skin, much thicker than 

 the epidermis, is called the true skin. 



The eye. The eye is the organ of the sense of sight. It is 

 protected by the eyelids, and when these are closed, the eye 

 sees no longer. It can, however, distinguish darkness and 

 light through them, as we may perceive by standing in the sun, 

 and bringing the hand or a dark object before the closed eyelids. 



When we look at the eye of any one, we first notice a black 

 hole in the centre, which is the pupil. Bound the pupil is a 

 coloured membrane in which the hole is pierced; and this is 

 called the iris. The iris is blue, grey, or brown, in different 

 persons. These tints are also sometimes slightly green, or 



