G6 NATTJItAL HISTORY. 



means of prevention of invasion by these parasites, a liberal salt ration with the 

 feed, and occasional doses of worm medicines will prove beneficial. The pus-eating 

 " great mouths" in their cysts are the most difficult to get at ; cases of rupture of 

 the stomach, which are not an infrequent occurrence among horses in India, are 

 often due to the weakening of the coats of that organ as caused by this parasite. 



3- The large headed ascaris (.4. megalocephala) is an enormous white round 

 worm, found generally in the small intestine, sometimes in the stomach His im- 

 portance as causing disease is in no way proportioned to his size. He probably gets 

 into the stomach simply by making a journey of exploration from the intestine. 

 The male is smaller than his spouse, and decidedly of second-rate importance in the 

 domestic circle, a very common feature among entozoa. When the syce lugubriously 

 brings one of these worms in the morning and urges that his horse wants medicine, 

 no apprehension should be excited in the owner's mind, but the horse will be the 

 better for a course of iron tonics. Yet these worms, though some of the largest, 

 are among the least formidable to which horses are liable. Only when they are 

 present in very large numbers do they cause mischief, and then purely in a mechani- 

 cal way, by blocking up the bowel; the wild ass recently examined by me had over 

 one hundred in hfm. They are rather rare among stabled horses in India. 



4. No part of the alimentary canal of the horse has a richer fauna than the 

 caecum and commencement of the colon. Three species are specially frequent 

 there; among them we will first of all notice a blood-sucking parasite, which, though 

 small in size, does much mischief. He can't be mistaken ; like a British infantryman 

 he is known by his red colour. His looks betray him, and enable us at once to distin- 

 guish between him and the armed strongyle of which we shall speak directly. He 

 is armed with four spines (Str. tetracanthus), which enable him to " tap" the small 

 blood vessels of the bowel when he is thirsty, a small red spot indicating where he 

 has been carrying on his operations.- His development is shown to ns in a ^ery 

 remarkable manner. If you examine the mucous membrane of the caecum yon will 

 find it dropsical and pulpy, as a result of irritation caused by these worms, and if 

 you peel it off and hold it up to the light, you will find the offenders in many cases 

 in enormous numbers, simply curled up in the substance of the membrane, some 

 scarcely visible with the naked eye others almost as large as the adults. They were 

 first described as " Triehina-like" organisms. These blood-suckers cause fatal 

 diarrhoea in colts, and may be considered among the most formidable to which the 

 horse is liable ; fortunately adult stabled horses do not much suffer from them. 

 In one outbreak over one hundred ponies are reported to have died from this cause. 



5. With these last are liable to be confounded the "palisade" or wandering 

 armed worms which occur in their adult form, especially in the caecum and colon : 

 they are larger and stiffer than the blood-suckers, and have a black line instead of a 

 rod one running up through them ; this is because they feed on the dark contents of 

 the bowel. They are, therefore, much less troublesome as adults than their red 

 companions. Their principal importance arises from their adventurous youth, during 

 which they wander strangely. Sometimes the young strongyles are seen in the eye, 

 but another species is much more frequent there, as we shall see directly. An armed 

 strongyle may turn up in almost any part of the body, but is extremely frequent in 

 the arteries of the bowels, where he gives rise to disease (aneurism). You can 

 seldom open the body of an old ass without finding in his bowel-arteries either young 

 armed strongyles, or traces that they have been there, depending on the time of year. 

 Those aneurisms are considered a frequent source of colic in the horse, at any rate 



