THE FOOT OF THE HORSE. 45 



villi, similar to those on the coronary cushion, which penetrate 

 into and supply the horny sole and frog, and in its meshes are 

 sustained the veins of the lower surface of the foot. See col- 

 ored plates. 



Continuous with the sensitive sole (and resembling it in 

 structure), and spreading over the entire outer or upper face of the 

 cotiin-bone until it is merged into the projecting substance of 

 the coronary cushion, is a villous sheath, called the keratogenous 

 membrane or laminal tissue, which completes the sensitive en- 

 velopes of the extremity of the digit. This laminal tissue ex- 

 hibits on the external face of the coflin-bone a series of fine 

 elastic leaves, called the sensitive laminae, which lie in parallel 

 rows, to the number of five or six hundred, running from above 

 to below, separated by narrow, somewhat deep channels, into 

 which are dovetailed similar horny leaves from the wall and 

 bars of the hoof. This leafy tissue is intimately attached to the 

 cofiin-bone through the medium of the reticulum, which also 

 supports the veins that supply its secretion. Like the other 

 vascular tissues, it is very richly supplied with blood-vessels and 

 nerves, and is at once the seat of acute sensation and the point 

 where the active changes of inflammation — villitis and lami- 

 nitis — are especially concentrated, becoming morbidly increased 

 through the effects of bad shoeing, hard pulling, or driving and 

 other like abuses. These parts are, in fact, the principal instru- 

 ments concerned in the sensory apparatuses of the horse's foot, 

 and the sensitive laminse play a most important mechanical part 

 in concurring, by their dovetailing with the horny laminae, in 

 securing the solidity of the hoof with the living parts as well as 

 in supporting the weight of the animal, which is distributed 

 through them upon the base of the wall. See colored plates. 



Circulation of the Foot. — As we have indicated in the 

 foregoing analysis, all the soft or sensitive tissues of the foot are 

 freely supplied with blood, in greater or less quantities, de- 



