36 LESSONS IN HORSE JUDGING. 



* iris,' a gluey discharge may occur from the sur- 

 faces of the ' iris,' and the back surface of the 



* iris' may then become stuck to the fore part of the 

 ' lens/ (See Fig. 5, /, /.) 



If you refer to the diagram of the iris, (Fig. 5, A) 

 you will see two or three little black bodies hang- 

 ing down, (Fig. 5, A 4) swinging from the roof of 

 the * pupil.' These are quite natural, and appear in 

 the eyes of many if not in most horses. 



We now come to the lens, which we represented 

 by taking out a glass from a pair of spectacles. 

 This lens (Fig. 5, I), I) is really placed close be- 

 hind the ' iris' or curtain, and is for the purpose 

 of focusing the rays of light so that they form 

 images on the thin membrane we have before spoken 

 of called the ' retina.' Get a pair of spectacles, or 

 a magnifying lens, and hold it in your right hand, 

 and with it throw a bright light from a window, or 

 a candle, or gas jet on to the back of your other 

 hand. Now move the lens gently to and fro, and 

 you will see a beautiful little image of the window- 

 frame, gas jet, or candle-light (whichever you are 

 using) on the back of your hand. Now you have 

 got this perfect image by moving the lens back- 

 wards and forwards between your hand and the 

 light, and you will have found that correct distance 

 is everything, that is to say, had you held the 

 lens an inch nearer or an inch further off, you 

 would not have got a sharp, clear image. Now 

 look at Fig. 5, D, and you will see that behind the 



