AS TO SOUNDNESS. 13 
first is an erect image of the light, and is produced 
by reflection from the surface of the cornea; the second 
is also erect, and is produced by reflection from the 
anterior surface of the lens; the third is inverted, and 
is due to reflection from’the concave posterior surface 
of the lens. The first two images move in the same 
direction as the light, the third in the opposite direc- 
tion. If the lens becomes opaque, of course the image 
from the posterior surface is lost, and that from the 
anterior surface also soon becomes indistinct. 
Before proceeding further, let me say, once for all, 
that this is not a course that admits of any discussion 
on disease, further than considering those disorders, 
and their various degrees of intensity, which are open 
to doubt as to their rendering a horse unfit for the 
ordinary requirements of work, and therefore unsound. 
The conjunctiva being more vascular, is less liable 
to permanent change than the cornea, so that we 
seldom look for alterations in it; but there are passing 
emergencies, such as conjunctivitis (cold in the eye), 
foreign bodies, and wounds inflicted with the whip, 
which prevent our examining either the conjunctiva 
or the eye. In these cases, time should be allowed 
for a cure to be effected before offering an opinion. 
If, however, the case cannot wait, then examine and 
give an opinion on the other points of the horse; but 
make yourself clearly understood by your client that 
you give no opinion whatever as to the ultimate sound- 
ness of the affected eye. I have known a piece of 
