DISEASES OF THE BONES 393 



covery by finding gradual improvement for a time by 

 fomentation and poultices, followed by irrigation and 

 stimulants to the coronet, and perhaps the animal is dis- 

 charged from hospital, to be returned after a few days 

 worse than ever. The disease then becomes insidious and 

 more pronounced, the nodding of the head, even at a walk, 

 more exaggerated, and, in fact, the animal seems afraid to 

 put his foot to the ground, and much resembles a horse 

 with an abscess in his foot, either from prick or picked up 

 nail. He absolutely nurses his foot. There is a certain 

 amount of heat always present. The disease being now 

 well developed, pressure is caused by the ends of the 



Fig. 153. — Effects of Periostitis on the Os Pedis. 



navicular bone, and they become involved at their 

 points by bony deposits. The causes of this disease 

 I attribute, firstly, to hereditary predisposition ; and, 

 secondly the exciting cause, standing confined on board 

 ship, where no doubt pedal congestion takes place. 

 And perhaps some subjects start it in their marches 

 in mobs down country in Australia. Concussion may 

 be the cause among older horses, but the specimens 

 photographed were taken from remounts, that had either 

 done no work or only very gentle work, in a deeply littered 

 riding school. 



'Treatment. — It is obvious from the position of this 



