432 



sive discharge from the numerous sebaceous glands and in bad cases 

 the formation of red, raw, excrescences {grapes) from the surface. It is 

 to be distinguished (1) from simple inflammation, in which the special 

 fetid discharge and the tendency to the formation of "grapes" are ab- 

 sent ; (2), from horsepox, in which the abundant exudate Ibrms a firm 

 yellow incrustation around the roots of the hair, and is embedded at in- 

 tervals in the pits formed by the individual pocks, and in which there 

 is no vascular excrescence; (3), from foot scabies (mange), in which the 

 presence of an acarus is distinctive ; (4), from lymphangitis, in which 

 the swelling appears suddenly extending around the entire Umbashigh 

 as the hock, and on the inner side of the thigh along the line of the vein 

 to the groin, and in which there is active fever, and (5) . from erysipelas, 

 in which there is active fever (wanting in grease), the i^nplication of the 

 deeper layers of the skin and of the parts beneath giving a boggy feel- 

 ing to the parts, the absence of the fetid, greasy discharge, and finally 

 a tendency to form pus loosely in the tissues without any limiting mem- 

 brane as in abscess. Another distinctive feature of grease is its tend- 

 ency to implicate the skin which secretes the bulbs or heels of the horny 

 frog and in the cleft of the frog, constituting the disease kuown as 

 canker. 



The predisposing causes of grease are essentially the same as those of 

 simple inflammation of the heel, so that the reader may consult the 

 preceding article, and though the specific fijugus {Oidium batracosis) is 

 essential to the disease, yet it usually remains inoperative unless the 

 field has been prepared by the coexistent predisposing factors. Local 

 irritants may cause simple inflammation, and may be essential to the 

 growth of the implanted germ, but without that germ it will not pro- 

 duce grease. 



The sijmptoms vary according to whether the disease comes on sud- 

 denly or more tardily. In the first case there is a sudden swelling of the 

 skin in the heel with heat, tenderness, itching, and stiflfuess, which is 

 lessened during exercise. In the slower forms there is only seen a slight 

 swelling after rest, and with little heat or inflammation for a week or 

 more. Even at this early stage a slightserous oozing may be detected. 

 As the swelling increases, extending up toward the hock or knees, the 

 hairs stand erect, and are bedewed by moisture no longer clear and 

 odorless, but grayish, milky, and fetid. The fetor of the discharge 

 draws attention to the part whenever one enters the stable, and the 

 swollen pastern and wet, matted hairs on the heel draw atteutiou to the 

 precise seat of the malady. If actively treated the disease may not ad- 

 vance farther, but if neglected the tense teuder skin cracks open, leav- 

 ing open sores from which vascular bleeding growths grow up, con- 

 stituting the 'grapes." The hair is shed, and the heel may appear but 

 as one mass of rounded, red, angry excrescences which bleed on hand- 

 ling and are covered with the now repulsivelv fetid decomposing dis- 

 charge. Daring this time there is little or no fever, the animal feeds 



