PARASITES AND PARASITIC DISEASES OF HORSES 19 
ment, and to withhold feed until after the carbon tetrachloride has 
been given. A suitable purgative for foals consists of castor oil, 4 to 
§ ounces, and neutral oil (mineral oil) 1 pint. This treatment has 
not had critical test to determine its precise value. 
Prevention.—Prevention consists in special precautions with ref- 
erence to stable sanitation, special care of foals, especially as regards 
clean bedding which should be changed daily, if possible. Other 
preventive measures are similar to those recommended in connection 
with the discussion of ascarids and blood strongyles. 
THE LARGE STRONGYLES OR PALISADE WORMS 
The large strongyles are roundworms commonly known as blood 
worms, red worms, sclerostomes, or palisade worms. They are red in 
Ficurp 12.—Portion of the tip of the cecum of a horse, showing blood strongyles 
attached to the inner lining of the gut. The large worms are SNS. equinus; the small 
ones are S. vulgaris. Natural size 
color and are commonly found firmly attached to the wall of the gut 
(fig. 12) by means of a rather formidable mouth cup. Three species 
of blood strongyles are of common occurrence in the colon and cecum 
of horses, as follows: 
The large strongyle, Strongylus equinus (fig. 18, C), is from 
about 114 to nearly 2 inches long by about one twenty-fifth to one- 
twelfth of an inch wide; the mouth cup contains three teeth. The 
toothless strongyle, Strongylus edentatus (fig. 18, A), contains no 
teeth in its mouth cup; otherwise it is similar in appearance to the 
large strongyle, although it is somewhat smaller, females being about 
114 inches long. The single-toothed strongyle, Strongylus vulgaris 
(fig. 18, B), is the smallest of the three species, and is from a little 
