84 



canal of the horse they get into the small vessels of the gut, and pass on into 

 the large arteries, and becoming embedded in the walls of these larger blood 

 vessels, they cause bulgings termed aneurisms. Lastly, these parasites 

 make their way out of the vessels, and thence endea\our to make for the 

 large gut, where they again change their skins, and, adhering to the mucous 

 lining of the bowel by means of their spines, attain sexual maturity. 



3 1 



Aneurysmal Armed Strongyi.k. 

 I, male, natural size ; 2, female, natural size ; 3, anterior extremity, highly- 

 magnified ; a, complete buccal capsule ; b, (lesphagus, or gullet ; c, intestine. 

 4, caudal extremity of the male worm ; A, hook and accessory 

 part. (Rayer). 



The aneurysms or swellings occur in a large percentage of horses and' 

 asses, and they vary in size from a pea to a man's head, and are met with in 

 animals six months old and upwards. The number of worms in an aneurism 

 varies, and is usually nine to ten, the highest .number in one horse being 121. 

 It has been said "that foals and yearlings suffer more from parasites in the 

 paddocks, than they do on adjoining farms where only a few animals are 

 bred."' "This is explained," says Dr. Cobbold, "by the relatively greater 

 amount of Qgg dispersion proceeding from the infected brood mares. It is 

 quite evident that the lives of many valuable animals arc annually sacrificed 

 by the neglect of hygienic arrangements. The palisade A\orm, as this 

 parasite is commonly called, is chiefly destructive to young animals, and, as 

 Mr. Percivall has remarked, is commonly the cause of lingering and hidden 

 disease terminating in death, without any suspicion on the part of the 

 practitioner as to the nature of the malady."' Treatment for these worms fs 

 not of much value. 



We have lastly to speak of the common hydatid of the horse. It is well 

 known that after death hydatids (Echinococci vctci'iHonnn) are 

 sometimes found in the various organs and glands of the horse, more 

 especially in the lungs, liver, and kidneys, and sometimes in the brain. 



