390 DISEASES OF HORSES AND CATTLE. 



mature worms which form cysts in the walls of the 

 intestine; within these cysts or tumors the young 

 worms are coiled up, or there may be openings in 

 the cyst through which the worm has recently 

 emerged. Fig. 23. From these cysts they pass 

 into the circulatory system, chiefly the anterior 

 mesenteric artery, but are also found in other ar- 

 teries in the abdominal cavity. Here they cause 

 more serious results, often producing aneurismal 

 tumors or dilations of the arteries. Here they 

 grow to the length of from three to four mm. 

 After a time they are carried with the blood into 

 the small blood vessels of the intestines where they 

 become again encysted, develop and leave the cysts 

 and adhere to the inner wall of the intestines and 

 after a time attain the stage of sexual maturity. 

 While these parasites are in the blood vessels they 

 disturb the circulation, weakening the walls of the 

 intestines, preventing them from performing their 

 function, causing colic and other derangements of 

 the intestines, and no doubt in some cases re- 

 sulting in the death of the animal. The worms in 

 the blood vessels and those encysted cannot be re- 

 moved by medicines, but when they become ma- 

 tured in the intestines they can usually be gotten 

 rid of by the same remedies as recommended for 

 round worms. 



