84 DISEASES OF THE HOG. 



in their motion. From experiments that have been 

 made it appears that the ova are never developed 

 in the animal body, but being discharged with the 

 feces retain their vitality for a long time, and if 

 placed in water become at the end of about eight 

 months and a half developed into embryos, about 

 one three-hundredth of an inch in length. It is 

 probable that these are carried by the rain and 

 other means into streams, wells, etc., whence the 

 drinking water is derived and thus they become 

 fully developed. There are no particular symp- 

 toms by which we can detect this worm from oth- 

 ers during the life of the animal, and the treatment 

 would be the same as for the thorn-headed worm. 

 Very often when worm medicine is given a variety 

 of worms will be discharged at the same time. 



ASCARIS SUILLA (ROUND WORM.) 



This is a round, smooth worm of considerable 

 size; the male usually reaches when fully devel- 

 oped six inches, and the female may be twice that 

 length. This worm usually does no harm when 

 there are only a few present. The animal will like- 

 ly keep in good health, but when they are numer- 

 ous they will disturb digestion and cause colicky 

 pains, loss of flesh, dry hair, morbid appetite, rest- 

 lessness and nervous twitching, and in some cases 

 fits. Cases are recorded in which they worked 

 through the walls of the intestines and, reaching 

 some of the other organs of the body caused death. 

 This worm generally inhabits the small intestine, 

 but not infrequently finds its way forward to the 



