44 



proceed to the various points of contact and union with the 

 horny laminae, and will yet admit of a certain amount of separ- 

 ation of the outer from the inner portion of the membrane, 

 allowing certain movements of the foot to be effected without 

 any undue strain of the filamentous and vascular connections 

 of the laminae. This elastic material' I shall have frequent 

 occasion to allude to again as the interperiosteal tissue, or pad. 



RELATIVE WEIGHTS SUSTAINED BY FORE AND HIND LIMBS. 



In further elucidation of the functions of the laminae, quoting 

 Spooner : 



" Let us consider the vast weight supported by each leg, and 

 the manner in which it is distributed. The weight of a 

 moderate sized horse is about twelve hundred weight ; this, 

 when the animal is standing is supported by the fore and hind 

 legs in the proportion of two-thirds by the former and one- 

 third by the latter. When the horse is in motion, say trotting, 

 this weight is supported alternately by one hind, and one fore 

 leg, so that each fore leg supports two-thirds of the animal's 

 gravity ; to this we must add the weight of the rider, and the 

 increased burden occasioned by the momentum of the horse's 

 action. We shall, therefore, be within bounds when we say 

 that each fore leg alternately bears a weight equal to the ani- 

 mal's entire gravity, all which is borne by the small pastern 

 bone, and is thus distributed to the parts below. A moderate 

 portion is first communicated to the elastic cushion, from 

 whence it is impressed on the lateral and inferior cartilages 

 and posterior part of the frog. The remainder, being the 

 principal portion, is transferred to the navicular and coffin- 

 bones, the former of which, by the interposition of the flexor 

 tendon, bears partly on the frog and partly on the sole ; and 

 the latter by the intervention of the laminae, distributes its 

 weight to the wall throughout its whole circumference, and a 

 very slight portion of it is borne by the sole, which may or 

 may not bear upon the ground. Thus at the same moment 



