PARASITIC DISEASES 167 



moved to a place where the hogs do' not have 

 access to. Unless the yards are clean and well 

 kept, we cannot get rid of them by destroying the 

 lice on the hogs and paying no attention to the 

 surroundings. 



THE COMMON ROUND WORM 



Ascaris Suilla — Duj. 



The common round worm is a parasite of the 

 small intestine. Occasionally a few of these 

 worms drift along with the alimentary matter into 

 the large intestine, but their presence here is ac- 

 cidental and they finally pass out with the ex- 

 crement. It is not uncommon to find common 

 round worms in the stornach of a hog that has 

 been dead for a short time, and when a large 

 number are present, they may pass on into the 

 oesophagus. This, is due to the reverse peristalsis 

 of the intestines, or the movement of the worms 

 themselves. The digestive juices in the stomach 

 will in a short time destroy them, and they are 

 unable to become a parasite of this part of the 

 digestive tract. Many stockmen have erroneous 

 ideas regarding this parasite. 



Description. — 'The body of the common round 

 worm is pinkish or yellowish white in color, smooth, 

 firm, and elastic, and tapening toward the extremi- 

 ties, the head end being more tapering than the 

 caudal extremity. The female, when grown, will 

 average about eleven inches in length, and the male 

 about seven inches. The latter can be readily dis- 



