_The treatment_ recommended for ridding sheep of this intestinal worm is largely preventive. Very little can be done with the medicinal treatment of a sheep whose intestinal tract is badly infested with this parasite. Good care and the feeding of a proper ration are the only curative measures that are effective in such cases. The occasional administration of a vermifuge for the purpose of ridding the digestive tract of worms, together with the frequent changing of pastures during the spring and summer, are the most effective preventive lines of treatment. The same treatment recommended for stomach worms may be used for this disease. INTESTINAL PARASITES OF HOGS.--The _Ascaris suis_ or _common round_ worm is very commonly found in the small intestine. It is quite frequently found in large numbers, almost filling the lumen of the intestine of an unthrifty pig (Fig. 75). It may also work its way into the bile duct. Sometimes, after a hog has died, this parasite migrates forward into the stomach and gullet. The _A. suis_ is from 4 to 10 inches (10 to 26 cm.) long. _The Echinorhynchus gigas_ or _thorn-headed_ worm is the most dangerous of all intestinal worms (Fig. 74). It is usually found with its proboscis or thorn imbedded in the wall of the small intestine. The Echinorhynchus is not as common a parasite as the Ascaride, and it is not usually present in large numbers. Usually, not more than a half-dozen of these worms are found in the intestine of a hog, but in some localities and in hogs that are allowed to root around manure piles and in clover pastures the herd may become badly infected with them and serious losses occur. The average length of the male is about 3 inches (8 cm.) and the female 10 inches (26 cm.). [Illustration: FIG. 77.--Whip-worms attached to wall of intestine.] [Illustration: FIG. 78.--Pin-worms in intestine.] The _Trichocephalus crenatus_ or _whip worm_ (Fig. 77) is slender or hair-like in its anterior two-thirds and thick posteriorly. It is from 1.5 to 2 inches (40 to 45 mm.) long. It is found in the caecum attached to the wall by the hair-like portion. The _OEsophagostomum dentatum_ or _pin worm_ is from 0.3 to 0.6 inch (8 to 15 mm.) long. It is found in the large intestine (Fig. 78).