OBSERVATIONS ON SOUNDNESS. 
459 
radiating fibres of the iris are of the same character with the 
circular; both sets constituting in man a peculiar variety of 
the non-striated form of muscular tissue. Through what 
nervous channel, however, the stimulus to this action is con¬ 
veyed, has not yet been clearly made out. The contraction 
of the pupil is evidently destined to exclude from the interior 
of the eye such an amount of light as would be injurious to 
it; whilst its dilatation in opposite circumstances admits the 
greatest possible number of rays. There is a contraction of 
the pupils, however, which takes place without any change 
in the amount of light. This occurs wdien the two eyes are 
made to converge strongly upon an}^ object brought very near 
them; and its purpose appears to be to prevent the rays 
from entering the eye at such a wdde angle, as would render 
it impossible for them all to be brought to their proper foci, 
and would thus produce an indistinct image.’^ These ob¬ 
servations refer more particularly to man. 
In treating this subject w’e must not lose sight of the 
situation of the eyes of the horse as contrasted with those of 
his master. The eyes of the horse are placed laterally, the 
eyes of man anteriorly. We possess one advantage in being 
able to view' very near objects which are situated in front of 
us, but the advantage is a very small one. The horse has 
many advantages; he can take cognisance of objects both 
laterally and posteriorly placed. We cannot do so wdth the 
same degree of accuracy. This is to be accounted for from 
the fact of our eyes being anteriorly placed, and the eyes of 
the horse, as I said before, being situated laterally, together 
with the greater size of the globe in that animal. The eye 
of man when compared to that of the horse is, I should 
imagine, similar to a small telescope and a large one, both 
complete in themselves, but the larger affording a greater 
field than the smaller. 
The w^ay to ascertain the seeing pow ers of the horse is, to 
aim a blow' at the head when standing before him. It will be 
observed he will have some difficulty in w'arding it, and of 
judging of the distance it is from him. Not so when you 
stand at his side. 
Shying is caused in most instances by imperfect vision, 
although the generality of horsemen believe it is a trick or 
habit acquired from idleness, and they refer it to playfulness, 
skittishness, &c. I am forced to believe, from much prac¬ 
tical experience amongst young horses as well as those more 
advanced in years, that in nineteen cases out of tw'enty the 
visual organ has not the pow'er of perceiving things aright. 
There are several causes in operation • to produce shying. I 
