THE ANGULAR OR SHARP MOUTH. 
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(a) the angular or sharp mouth, the so-called prognathous jaw. 
Under ordinary circumstances mastication causes general wear of the 
entire grinding surface of the molars, hut if any part fails to be worn, 
that portion will become too long. Owing to the peculiar relations of the 
two jaws, the points which generally escape wear are on the inner side of 
the lower row and on the outer side of the upper. Either single teeth, 
an entire row, or even several rows, may be involved. If the two rows do 
not terminate at the same point, the upper molar being too fai forwaid, 
or the first lower molar too far back, the unopposed points will continue 
to grow until their sharp elongations may injure the opposite gum. 
Causes. This irregularity may be caused by a narrow formation of 
the lower jaw, as was shown by Defay, and latei by Giinthei and 
others, though such formation is not the only cause, otheiwise the 
ox, which very rarely exhibits the condition, should be a frequent 
sufferer. It is assisted by limitation of the movements of mastication, 
which in its turn is said by Lorge to be dependent on faulty development 
of the muscles of the jaw. In chewing, the ox moves the jaw laterally 
through a wide angle ; hence, although its upper and lower rows of 
molars do not coincide, it very seldom suffers from sharp edges. As 
soon as sharp edges form on the teeth, the inside of the cheeks may be 
wounded. The further limitation thus placed on movements of the jaw 
aggravates the production of sharp edges, and the mischief incieases. 
It is easy to operate on the sharp edges and points of the teeth, but this 
does not remove the cause, and the malady is liable to recur. The shaip 
edges of the lower teeth lacerate the tongue, while those of the upper 
iniure the cheek. These injuries may eventually induce general vasting 
and loss of power. Such a condition is seen especially in old lioises, 
seldom in other animals. 
Symptoms. The animal feeds badly, chews slowly and cautiously, and 
holds the head to one side. Food is often dropped from the mouth into 
the manger ; portions also remain between the teeth and cheeks ; while 
movements of the jaws or tongue are as much as possible avoided. 
Wounds of the mucous membrane produce copious salivation. Jessen 
remarked that this condition was formerly often overlooked; but that 
its importance is apt nowadays to be over-estimated, and the diagnosis 
of (( sharp teeth is sometimes used as a cloak foi ignorance. Inegu 
larities, however, frequently produce no mischief, and can only be regarded 
as causes of imperfect mastication when they occasion wounds of the 
tongue or cheeks. Unless where very marked, they are unimportant in 
young animals. 
Treatment. Sharp points or edges can either be removed with the rasp 
(fig. 7) or one of the several forms of chisel. (Tigs. 8, 9, and 10.) If 
