The commonly used methods of applying treatment are dipping, spraying, medicated wallows, medicated bedding, hog oilers, and hand application.

Dipping is the most thorough and effective method. Spraying, if thoroughly done, also is effective. Medicated wallows, if properly constructed and maintained, often give satisfactory results. The use of hog oilers, medicated bedding, and hand applications usually checks the spread of hog mange but seldom produces a cure.

Oils and lime-sulfur solution used to be the most commonly and successfully used remedies for sarcoptic mange of hogs. Some of the newer insecticides have largely replaced the older remedies. Among them are benzene hexachloride (BHC), lindane, and chlordane, all of which are marketed in the form of wettable powder and oil emulsions.

BHC was the first to be tested widely and recommended for sarcoptic mange. Its greatest drawback is its disagreeable, pungent, musty odor, which persists for weeks on treated swine and all objects with which it comes in contact. Lindane is practically odorless and has largely replaced BHC as a remedy for mange and many other external parasites of livestock.

DIPS, SPRAYS, OR MEDICATED WALLOWS made up with BHC or lindane preparations should contain at least 0.1 percent of the gamma isomer the principal insecticidal ingredient. A concentration of 0.13 percent is most satisfactory. Like remedies made up with chlordane should contain 0.5 percent of that chemical.

Sarcoptic mange can be kept from spreading in a flock if the swine and their bedding are thoroughly dusted with lindane or BHC dusts that contain 1.0 percent gamma isomer. In very cold or inclement weather, dusting may be resorted to until dipping or spraying is feasible.

In treating swine for mange, it is important to see that all body surfaces, including the inside of the cars, are thoroughly covered with the remedy being used, and that all animals in the herd are so treated.

When spraying a swine herd for mange, only a few animals should be treated at one time. In that way the thorough wetting of each individual can be assured. It is usually advantageous to dip the smaller pigs in a barrel or tub containing the spray material.

After dipping or spraying, swine should be kept out of the sun and wind for a few hours if possible. That practice allows the dip or spray material to soak into the mange lesions, so that the mites in deep wrinkles and beneath the crusts can be destroyed before it dries on the surface.

One thorough dipping or spraying with BHC, lindane, or chlordane will usually eradicate sarcoptic hog mange from swine. Extensive cases, especially those of long standing with thickly crusted lesions, sometimes require a second treatment. It is good practice to treat such cases a second time about 10 days after the first application.

DEMODECTIC, OR FOLLICULAR, MANGE of swine is caused by minute, wormlike mites known as Demodex folliculorum suis or Demodex plylloides.

Similar follicle mites infest dogs, cattle, other animals, and people.

The parasites are truly microscopic in size. The full-grown female is only about one one-hundredth inch long. They penetrate the hair follicles and oil glands of the skin, where they complete their life cycle. Small numbers of them apparently cause the animal no serious inconvenience, but occasionally they increase rapidly and cause well-marked lesions in the skin of the animal.

THE DISEASE IS CONTAGIOUS to hogs of all classes but is encountered much less often than the more common sarcoptic form of mange.

The lesions usually appear first on the snout or around the eyelids. They spread slowly over the underside of the neck, breast, abdomen, inner sides of the legs, and other parts of the body, where the skin is thin and tender. The back and upper parts of the sides, where the skin is thick and tough, are seldom affected.

In the early stages, the affected skin may be red and scurfy. Small, hard, nodular lumps, ranging in size from that of a pinhead to that of a hazelnut, appear in the skin. The nodules may be dark red or light red, with a whitish or cream-colored center.

As the disease advances, the nodules break and discharge a creamlike pus or lumps of matter of a cheeselike consistency. Two or more of the nodules may break and run together, forming cavities in which pus may form.

No SPECIFIC CURE for demodectic mange is known. Frequent clippings or sprayings with crude petroleum check its progress and heal many old lesions.

Repeated treatments with some of the newer insecticides, especially BHC or lindane, likewise may control the disease.

Herds in which demodectic mange appears should be treated. Any animals that have advanced cases and do not respond to treatment should be killed. The rest of the herd should be fattened for market and disposed of. The premises should then be cleaned and disinfected before they are restocked with healthy swine.

N. G. COBBETT, a veterinarian in the Animal Disease and Parasite Research Branch, Agricultural Research Service, is stationed at Albuquerque, N. Mex. Upon graduation from the Colorado Agricultural and Mechanical College in 1921, he joined the former Bureau of Animal Industry. Since 1928 he has engaged in research investigations pertaining to external parasites affecting livestock and poultry.