414 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



Causes. Edema generally results from a weakened state of 

 the system, arising from previous disease. It may also be de- 

 pendent upon a functional derangement of the kidneys, upon 

 weak circulation, or obstruction to the flow of blood through the 

 lungs. In debilitated animals and in some animals heavily in- 

 fested with parasites there is swelling of the dewlap or of the fold 

 of skin between the jaws. 



Symptoms. Painless swelling of a limb, udder, lower surface 

 of abdomen, or lower jaw becomes apparent. This may increase in 

 dimensions for several days, or may attain its maximum in 

 less than twenty-four hours. Unless complicated with some acute 

 disease of a specific character, there is not much, if any, constitu- 

 tional disturbance. The deep layer of the skin is infiltrated with 

 Berum, which gives it the characteristic condition of pitting under 

 pressure. 



Treatment. When the cause can be ascertained and removed, 

 we will have a reasonable expectation of seeing the edema disappear. 

 When no direct specific cause can be discovered and the animal is 

 debilitated, give general tonic. If, on the contrary, it is in good 

 flesh, give a purgative, followed by half an ounce of acetate of potash 

 twice a day. External applications are useless. Edema may be dis- 

 tinguished from erysipelas or anthrax by the absence of pain and 

 fever. 



DERMOID AND SEBACEOUS CYSTS (WENS). 



A dermoid cyst is formed by an involution of the skin, with a 

 growth of hair on the inner wall of the sac. It may become em- 

 bedded deeply in the tissues subcutaneously, or may just penetrate 

 the thickness of the skin, where it is movable and painless. They 

 are generally found within the ear or at its base, although they may 

 form on any part of the body. Usually they have a small opening, 

 from which a thick, cheesy matter can be squeezed out. The ra- 

 tional treatment is to dissect them out. 



Sebaceous cysts appear not unlike the former. They are 

 formed by a dilatation of the hair follicle and sebaceous duct within 

 the skin, and contain a gray or yellowish sebaceous mass. The 

 tumor may attain the size of a cherry stone or a walnut. Generally 

 they are round, movable, and painless, soft or doughy in consistency, 

 and covered with skin and hair. They develop slowly. The best 

 treatment is to dissect out the sac with contents entire. 



VERRUCA (WARTS). 



Cattle are affected with two varieties of warts. One, the verruca 

 vulgaris, is composed of a cluster of enlarged papilla?, covered with 

 a thickened epidermis, the number of papilla? determining the 

 breadth and their length its height. They are generally circular in 

 figure, slightly roughened on the surface, and spring from the skin 

 by a broad base. Occasionally large numbers of very thin, long, 

 pedunculated warts grow from the skin of the ear, lips, about the 

 eyes, and vulva. Another variety, the verruca acuminata, sometimes 

 erroneously denominated epithelial cancers, are irregularly shaped 

 elevations, tufted or club-shaped, occasionally existing as thick, 



