1096 DISEASES OF THE FOOT. 



to time, and the local treatment should be supplemented by internal 

 medication with such materials as arsenic or the iodides. The use 

 of caustics, or of the actual cautery, should not be pushed to excess, 

 and when the discharge ceases it is better to replace them with milder 

 applications and with disinfectants. Although the principles here 

 set forth arc sufficient to guide treatment, yet close personal obser- 

 vation is necessary, and in many cases it may appear advisable to 

 try certain of the other remedies suggested. 



G. DISEASES OF THE CLAWS IN CATTLE AND SHEEP. 



Disease processes in the claws of ruminants show a general resem- 

 blance to diseases of the horse's hoof, though they exhibit many 

 special features, dependent chiefly on the duplicate formation of 

 the claws, and on other anatomical peculiarities. 



The claw consists of a horny wall surmounted by a coronary band, 

 and of a horny sole with bulbs similar to those of the horse's heel. These 

 perform the function of the frog, which, with the bars, is absent in 

 ruminants. In medium-sized cattle the horny Avail attains, on its outer 

 part, a thickness of about ^ of an inch, whilst the inner, which lies in 

 contact with its fellow, is scarcely ^ of an inch, and is considerably shorter 

 than the outer on account of the sole sloping obliquely upwards to become 

 continuous with it. 



The horny sole also has a thickness of about T 3 6 of an inch, and reaches 

 from the toe to the posterior third of the ground surface of the claw, where 

 it becomes continuous with the wall. Above the wall, and between it and 

 the tendon of the flexor pedis perforans, is a mass of firm connective tissue. 

 to some extent corresponding to the fibro-fatty frog, and containing a 

 large quantity of fat. 



The pedal- joint (Fig. 581) lies near the centre between the toe and 

 ball of the foot, its middle point (b) being somewhat nearer to the toe than 

 to the wall, and about £ of an inch below the coronary border of the wall. 

 A straight line drawn obliquely from the front of the interdigital space 

 to the termination of the horny sole in the walls would nearly coincide 

 with the lower border of the joint (Figs. 581, 582). The posterior end of the 

 os pedis lies between c and d in Figs. 581, 582, behind c lies the navicular 

 bone, which completes the formation of the pedal-joint. The coronet- 

 joint is generally about £ of an inch above the coronary border of the wall 

 of the claw ; the position of the fetlock can, of course, be determined by 

 palpation. 



The sensitive wall and coronary band differ little from the corresponding 

 portions of the horse's hoof, though the band is broader, and reaches down- 

 wards almost to the middle of the horny wall. The sensitive sole presents 

 a general resemblance to that of the horse, but the postero-internal portion 

 possesses a modified subcutis somewhat analogous to the sensitive frog. 

 The surface of the sole may be divided into toe and bulb, a fact which 

 accounts for the severity of all suppurating processes in the bulbar portion. 

 Between the claws the coronary band becomes continuous with the skin, 

 which is hairless, and covered with a thick but slightly horny epidermis. 



