Diseases of the -Foot 367 



which forms the hoof-wall is prolonged as a band around 

 the upper margin of the wall, and from the heels forward 

 above the cleft at each side of the frog. It is shaggy 

 throughout with soft conical processes (villi), from ^ to 2 

 lines in length, which extend into the horny tubes and 

 secrete them. The membrane forming the sole is covered 

 by similar villi which pass into the horny tubes of the sole, 

 and that covering the elastic frog has corresponding but 

 smaller villi. Between the fibrous net-work and the inner 

 surface of the hoof-wall and bars, the mode of union is 

 by a series of 600 to 600 leaves (laminae) projecting on a d 

 average 1^ or 2 hnes, and each having on its lateral aspects 

 from 30 to 60 microscopic secondary laminae. These are 

 interleaved with the same number of primary and second- 

 ary horny laminae forming an extent of connecting surface 

 which would beget incredulity if named. These inner 

 fibrous and vascular laminae secrete the horny laminae that 

 are interleaved with them, besides giving off an amount of 

 moisture, which being absorbed by the cells of the adjacent 

 horny wall, serves to keep that soft, yielding and tough. 

 So intimate is the union between each of these secreting 

 surfaces and the horn covering it, that the fibrous net-work 

 will often be torn from the bone, rather than the horn from 

 the sensitive parts. This is above all true of the laminae. 

 This close connection further renders active inflammation 

 in these structures acutely painful, for there being no loose 

 tissue to yield to the exudation, it compresses these dense 

 structures and violently tears them apart. Thus extensive 

 effusions of serum or pus endanger separation and shed- 

 ding of the hoof. A less acute inflammation of any of 

 those secreting surfaces leads to the production of un- 

 healthy horny growths. Thus disease of the see-eting 

 membrane at the coronet will determine a bulging, ragged, 

 brittle hne of horn from above downward on the hoof- 

 wall, or, what is worse, a crack or fissure extending to the 

 (juiek. Disease of the laminae will determine the forma- 

 tion of a great mass of soft, spongy, yielding horn between 



