The ulceration of the surface rapidly extends. The thin upper edges of the inner walls of the hoof are disorganized, and an ulceration is established between the hoof and the fleshy sole. A purulent fetid matter is discharged from the cavity. The extent of the separation increases daily, and the ulcers also form sinuses deep into the fleshy sole. The bottom of the hoof disappears, eaten away by the acrid matter, and the outer walls, entirely separated from the flesh, hang only by their attachments at the coronet. The whole fleshy sole is now entirely disorganized, and the entire foot is a mass of black, putrid ulceration; or, as more commonly happens, the fly has struck it, and a dense mass of writhing maggots cover the surface, and burrow in every cavity. The fore-feet are generally first attacked; and, most usually but one of them. The animal at first manifests but little constitutional disturbance, and eats as usual. By the time that any considerable disorganization of the structures has taken place in the first foot, and sometimes sooner, the other forefoot is attacked. That becoming as lame as the first, the miserable animal seeks its food on its knees; and, if forced to rise, its strange, hobbling gait betrays the intense agony occasioned by bringing its feet in contact with the ground. There is a bare spot under the brisket, of the size of a man's hand, which looks red and inflamed. There is a degree of general fever, and the appetite is dull. The animal rapidly loses condition. The appearance of the maggot soon closes the scene. Where the rotten foot is brought in contact with the side, in lying down, the filthy, ulcerous matter adheres to, and saturates the short wool--it being but a month and a half, or two months, after shearing--and maggots are either carried there by the foot, or they are soon generated there. A black crust is speedily formed round the spot, which is the decomposition of the surrounding structures; and innumerable maggots are at work below, burrowing into the integuments and muscles, and eating up the wretched animal alive. The black, festering mass rapidly spreads, and the poor sufferer perishes, apparently in tortures the most excruciating. Sometimes but one forefoot is attacked, and subsequently one or both hind ones. There is no uniformity in this particular; and it is a singular fact that, when two or even three of the feet are dreadfully diseased, the fourth may be entirely sound. So, also, one foot may be cured, while every other one is laboring under the malady. The highly offensive odor of the ulcerated feet is so peculiar that it is strictly characteristic of the disease, and would reveal its character, to one familiar with it, in the darkest night.