DISEASE OF THE OS PEDIS. 329 



Symptoms. — Swelling on the front of tlie coronet, varying in 

 size from that of a liazel nut to that of a pigeon's egg, witli 

 lameness, which is often very persistent. The peculiarity of 

 gait is manifested by the horse putting the heel down first, and 

 often taking the foot up very quickly as soon as the toe comes 

 in contact with the ground. There will he pain on pressure, 

 and some heat ; now and then the skin over the enlargement 

 sloughs, leaving a wound, which heals with difficulty; or a 

 wound may be present from the first, if the injury has been due 

 to external violence. 



Treatment. — Low-heeled bar shoe; fomentations, poultices, 

 and rest ; succeeded by blisters, or the application of the actual 

 cautery. In some cases the lameness resists the most active 

 treatment, and upon examination after death, caries is found to 

 have destroyed the pyramid of the bone, and extended into the 

 pedal articulation. Neurotomy, if there be a good foot, might 

 be tried in cases that resist all other treatment. 



n. — OSSIFICATION OF THE LATERAL CAETILAGES. 



Side-Bones. — Commonly met with in heavy horses, and in 

 the fore feet. I have seen the lateral cartilages of the hind ones 

 ossified ; but this is very rare, and, so far as I know, never occa- 

 sions lameness. 



The lateral cartilages are two thin plates of fibro-cartilage, of 

 an irregularly quadrangular form, surrounding the wings of the 

 OS pedis, which, in virtue of their elasticity, assist the sensitive 

 frog and soft structures of the foot in regaining their natural 

 position after being pressed upwards and outwards by the weight 

 of the animal. An opinion prevails that these fibro-cartilagin- 

 ous bodies assist in the expansion of the foot. Undoubtedly 

 they expand at their posterior border each time the animal puts 

 his foot to the ground ; but in this expansion of the heel they 

 are mere passive agents, being, in fact, pressed outwards by the 

 structures contained in the space between them. They are, 

 however, active agents in causing the contraction of the heel; 

 for when the pressure is removed from their inner surfaces, they 

 then tend to assume their natural position in virtue of their 

 elasticity; and the pressure they exercise upon the sensitive 

 frog forces the heel into its original shape. Briefly, they may 



