farmers' institutes. 799 



ping tank. The tank should be sunk in the ground and contain enough 

 of the solution to cover the hog when it jumps into it. 



Crude oil is the cheapest material to use as a dip. The tank is filled 

 with water to the desired depth and one inch of the oil poured on the top 

 of it. The hogs are then driven through, and a thin layer of oil is de- 

 posited on every part of the animal. 



Mange. Scabies.— This affection of the pig is frequently alluded to 

 in journals devoted to the swine industry and is described in nearly all of 

 the old Morks on diseases of swine. It is a rare affection, and of little 

 economic importance. Because of the disease being so frequently men- 

 tioned we include it with the other parasitic diseases. 



Hogs have two forms of mange— the sarcoptic form, due to the Sar- 

 contes scabies var. suis, and the demodecic form, due to Demodex folli- 

 cul.orum var. suis. 



The domodex of the pig (Demodex follieulorum var. Suis Simon) is a 

 worm-like parasite and shaped something like a laurel leaf and about one 

 one-hundredth of an inch in length and one one-fifth as broad. It com- 

 prises three parts— head, thorax and abdomen, the first two being joined 

 in a single organ. The mouth parts are horseshoe shaped. Their length 

 and the cephlo thorax is about equal to the length of the abdomen. The 

 mouth parts comprise: First, a pair of mandibles; second, a pair of 

 jaws: third, a narrow, tongue. On the sides of the thorax are four 

 pairs of short, mobile legs formed of three parts, the last part being 

 fitted with two claws. The abdomen is long, conical and straited trans- 

 versely. It shows at the anterior part of its ventral face a longitudinal 

 slit; the anus, which is much larger in the female than in tne male, 

 may serve for copulation and ovulation. The abdomen of the male is 

 less developed than that of the female, and possesses a genital armature 

 situated immediately in front of the anus. 



The young parasites are small and narrow and have but three pairs 

 of legs. The eggs average twenty-five-hundredths of an inch long, and 

 are oval in shape. The larvae undergo three metamorphoses before reach- 

 ing the adult stage. It no doubt passes through the different stages of 

 development in the follicles of the skin, but may migrate over the surface 

 of tlie skin when they reach tlie adult stage and before laying eggs. 



Symptoms— The finer parts of tht; skin are affected; the snout, neck, 

 chest, abdomen, flank and inner part of the thighs. The inflammation 

 begins In the region of the hair follicles and sebacious glands. Pimples 

 and ]»ustules varying in size from that of a grain of sand to that of a 

 hazel nut appear. As the disease progresses large purulent islands vary- 

 ing in size and containing many acari are formed. Ulceration may fol- 

 low. In the older diseased areas and when the disease lasts for a long 

 time, the skin becomes sclerotic and many times its normal thickness. 

 Inside of the pimples the mites can be found in all stages of develop- 

 ment. In the small abscesses there may be from fifty to one hundred, 



