DISEASES OF THE OX AND SHEEP. 201 



among the merino sheep, oeing apparently more severe in warm 

 weather than in more inclement seasons. This contagious form 

 of foot-rot is probahly caused by a parasitic vegetable growth, 

 and it may often begin even at the top of the hoof — in fact, at any 

 part where the virus happens to come into contact with the hoof. 

 When the disease has thoroughly established itself, the sheep, 

 while grazing, may be seen upon their knees, so much pain does 

 it cause them to put their feet to the ground. The wool is thereby 

 worn off, and the knees will therefore be seen to be bare. The 

 disease begins by the vascular structures of the foot becoming 

 inflamed, and then ulcerating, and giving rise to the formation 

 of an offensive purulent fluid, and ultimately the hoofs may come 

 off, and the disease spread upwards into the bones. The malady 

 is actually communicated by contagion ; but long marches, lack 

 of attention to the hoofs, rank grass, standing on manure, the 

 entrance of dirt into the hoofs, ground which is either too wet or 

 too dry, or hot, stony, or sandy, may be mentioned as additional 

 factors. As a rule, only one foot is attacked at first; but the 

 malady soon passes on to the other feet. 



The earliest sign may be that one of the fore limbs is slightly 

 lame. A day or two after this the hoofs become hot and painful, 

 especially in the interval between the claws. In fact, the skin 

 between the claws and above the hoof is red, and exhibits at first 

 pimples, then vesicles, then pustules, and a foul oily material is 

 poured out. Soon small ulcers appear, and they gradually unite, 

 and the discharge which comes from them is yellow and sticky, 

 and gives out a peculiar ammoniacal odour. Perhaps the first 

 sign of disturbance is that the heels become hot, and this 

 inflammation increases rapidly. The skin at the top of the cleft 

 over the heels becomes in the first instance moist and red, and it 

 j)resents a chafed or eroded or even a slightly corrugated look. 

 It then becomes sore, the discharge increases, and ulceration 

 supervenes. The inner walls of the hoof also ulcerate, and the 

 ulcerating process may even give rise to the penetration of 

 these thin walls. If the horn is removed, it will be seen that the 

 connection between the horn and the fleshy sole is severed, and 

 a very fetid or purulent matter is exuded in the crack. 



In about three and a half weeks' time the hoof may be seen to 

 be separating towards the heel. In fact, the hoof gradually 

 •comes off from before to behind, and a dark, greasy, offensive 



