616 DISEASES OF SWINE 



are swollen, red in appearance, and vary in size from that of a pea 

 to as large as a half-dollar. In some instances a number of the 

 blotches run together to form one large area which may be several 

 inches square. In a few hours the spots begin to fade at the center, 

 and may extend at the margin, the edge of the spot always being 

 red in color. 



There is an intense itching accompanying these lesions, and the 

 hog will rub and scratch itself against the fence, posts, or any other 

 object that is handy. This irritation causes loss of appetite, some 

 fever, restlessness, and even loss of weight, and an unthrifty ap- 

 pearance. 



Course. — Urticaria is not a serious disease in itself, and the 

 principal importance lies in the fact that it points to something 

 being wrong with the digestive apparatus or the manner of feeding 

 in most cases. The usual course of the disease in the hog is about 

 four to six days, and the lesions gradually fade away and do not 

 leave any mark behind. In unusually severe cases blisters may 

 form and the skin scale off over the areas where the blotches were 

 located. 



Treatment. — In the prevention of this disease important stress 

 must be laid upon the necessity of keeping hogs in clean feed lots, 

 and keeping the animals clean and free from lice and other irritating 

 parasites. Animals that are kept in dirty, filthy feed lots, and al- 

 lowed to wallow in a muddy old hog-wahow, cannot be expected to 

 keep free from skin diseases. Lice also are an important factor not 

 only in this disease, but also in causing unthriftiness in swine. Care 

 must be exercised in selecting preparations to remove lice that 

 strong irritating solutions are not used which would cause more 

 harm than the lice. A 2 per cent, dip of some of the coal-tar dis- 

 infectants, such as kresol, creohn, or similar preparations, is the 

 most effective method for removal of these parasites. It is of no 

 use to dip the animals, however, unless an effort is made at the 

 same time to clean up the feed lots and keep them clean, so as to 

 prevent reinfection of the hogs as soon as they get out of the dipping 

 vat. In connection with the dipping of the herd, it is advisable 

 in hot weather to keep them out of the sun for a few hours a,fter 

 they have been dipped. 



Another important point in the prevention of this disease is 



