362 A Manual of Veterinary Physiology. 



stand up for any length of time, the exercise overcoming 

 the tendency of the laminae to congestion from continual 

 strain ; and the feet not only become cool, but the animal 

 may continue standing for a considerable time if daily 

 exercised. The value of exercise in the treatment of 

 laminitis, first taught us by Mr. Broad, of Bath, is based on 

 the most satisfactory physiological basis. 



If any doubt exists as to the function of the laminse in 

 supporting the weight of the horse's body, we have only to 

 look at the processes which occur in them as the result of 

 disease. Laminitis is often attended by separation of the 

 horny and sensitive lamina}, when the horse's weight being 

 no longer properly supported, the pedal bone under the 

 influence of the animal's weight is actually forced through 

 the sole of the foot. 



Anti- concussion Mechanism. — The arrangements which 

 exist to save the foot from concussion are numerous. We 

 have, in the first instance, the highly elastic and india- 

 rubber-like horny frog, the fibro-fatty or plantar cushion, 

 the elastic cartilages of the foot, the elastic posterior wall, 

 and, moreover, the descent of the sensitive foot within its 

 glove, the horny foot. 



The descent of the sensitive foot has been as strongly 

 denied as the expansion of the posterior wall, but there is no 

 difficulty in demonstrating it,* and we can see the value of 

 this function. The foot comes to the ground either flat or the 

 frog first ; I believe that in the slower paces it comes to the 

 ground nearly flat, but in the faster paces there is no doubt 

 whatever but what the frog comes first to the ground, viz., 

 the posterior part of the foot first, the anterior part last. 

 The frog, from its peculiar physical condition, is not only 

 adapted to prevent the horse from slipping, to give him a 

 grip on the ground, but also to save the foot and leg from 

 concussion ; that is the reason why it comes first to the 

 ground. Concussion to the anterior part of the foot is 

 prevented by a slight up-and-down play between the 

 lamina- and the pedal bone, through the medium of the 

 * See the articles alluded to on [>. 358. 



