UNSOUNDNESS 247 



i5ults. The disease is more common among light harness horses. 

 It is detected by "pointing" in the stabk's; after the case is well 

 developed, lameness grows worse if the horse continnes to work 

 and generally improves with long rest only to return again 

 with work. 



The history of navicular trouble is significant. Slow and 

 vague in its onset, the lameness is variable and irregular at 

 first. Later the horse "goes on his toes" in a stilty manner and 



Fig. 86. — Navicular Disease. (M. U. E.) 



1. Normal navicular bone. 



2. p]xostosis (bouv enlargenicnt) with fracture. 



3. Exostosis with 'extensive ulceration of the articular surface. 



4. 5, 6, 7. Varying types of exostosis. 



Stumbles easily if both feet are affected. There may be heat 

 in the hollow of the heels and pressure of the thumb in this 

 hollow together with sharp flexion of the toe causes increased 

 lameness when the liorse is made to move. 



Dummy. — ^A dummy is a horse with a l)rain disease which is 

 indicated by peculiar attitude and stupid actions. The liorse 

 is listless, stands with his licad down, jicrhaps resting it on the 

 manger and fre(|ucntly rests one foot upon the coronet of the 

 other. He drinks with his mouth deep in the water; walks with 

 his head low, although stepping high or dragging tiie feet; is 

 unal)le to back; and is subject to sudden brain disturbances 

 such as unreasonable fright and panic. Such a horse will 

 usually leave the front legs crossed if they are put in this un- 



