UNSOUNDNESS 247 



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

 It is detected by "pointing" in the stables; after the case is well 

 developed, lameness grows worse if the horse continues 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. H. B.) 



1. Normal navicular bone. 



2. Exostosis (bony enlargement) 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 horse is made to move. 



Dummy. — A dummy is a horse with a brain disease which is 

 indicated by peculiar attitude and stupid actions. The horse 

 is listless, stands with his head down, perhaps resting it on the 

 manger and frequently 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 the feet; is 

 unable 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- 



