10 



stomach worm, because of the tumors which they produce. The 

 tumors interfere to a considerable extent with the proper functioning 

 of the stomach. When large tumors are situated near the junction 

 of the stomach and intestine they interfere mechanically with the 

 passage of food. The most evident injury occasioned by the large 

 stomach worms is produced by the larvae which get into the skin of 

 horses where they are commonly associated with a skin disease known 

 as summer sores. 



Treatment. — Carbon disulphide or carbon tetrachloride, in capsule 

 or by stomach tube, may be used for the removal of stomach worms, 

 although these drugs will probably remove only those worms which 

 are free in the stomach contents. The worms in the mucous lining 

 and in tumors in the wall of the organ are probably inaccessible 

 to the drugs now in use. The lining of a horse's stomach is normally 

 covered by a thick layer of tenacious mucus. Preliminary washing 

 of the stomach with warm water or a weak alkaline solution by means 

 of a stomach tube may mechanically remove some of the worms 

 and, by dislodging the mucus, may expose the remaining parasites 

 more fully to the action of the drugs. 



Carbon disulphide may be given in doses of 6 fluid drams (24 cubic 

 centimeters) for a 1,000-pound animal, or at a dose rate of 1.5 fluid 

 drams (6 cubic centimeters) for each 250 pounds of weight. No 

 purgative should be used with this treatment. The animal should be 

 fasted from 18 to 24 hours before treatment. 



Carbon tetrachloride may be given in doses of 6 to 12 fluid drams 

 (25 to 50 cubic centimeters) for a 1,000-pound animal. No purgative 

 is needed with this treatment. The animal should be fasted for 

 24 hours before treatment. 



Prevention. — Prevention of stomach-worm infestation in horses 

 involves the storage of manure in closed containers, in order to de- 

 crease the number of flies which breed in manure, or the application 

 of other control measures designed to prevent flies from breeding. 

 The use of containers for storing manure with a view to destroying 

 eggs and larvae of parasites is discussed subsequently in this circular. 

 The United States Bureau of Entomology has devised a trap de- 

 signed to destroy fly maggots which breed in manure. The trap is 

 based on the observation that maggots, when fully grown, migrate 

 out of moist manure and if they are permitted to escape through 

 spaces between the boards of an open manure platform raised on 

 posts and set in a concrete basin of water, they are caught in the 

 basin and drowned. This and various other methods of controlling 

 the house fly and stable fly are given in Farmers' Bulletins Nos. 1408 

 and 1097. 



SUMMER SOKES 



A skin disease of horses, known as summer sores and characterized 

 by pronounced skin lesions, is associated in some parts of the world, 

 including the United States, with the larva? of the large stomach 

 worms of horses. The sores may be as small as a millet seed, but 

 are usually about the size of a pea and may attain a size about an 

 inch in diameter. The sores are covered by a soft, brownish-red, 

 pulpy material with cracks or furrows which are filled with pus. 

 In the midst of the softened mass there are small, rounded granu- 

 lations which are firm in texture, 



