EED WORMS. 403 



husk, is likely to be favourable to the growth and development 

 of palisade and red worms, and should therefore be avoided as 

 pasture lands by horse-owners. The same remark applies to the 

 parasites (flukes) which often give rise to disease of the liver in 

 sheep. 



Mr. Shipley tells us that " yearlings are m.ore liable to be 

 affected than adults ; in fact it is seen only rarely in five-year- 

 olds and upwards. Moreover, in adults the effects are nothing 

 like so disastrous." 



The mode of attack of the sclerostoma tetracanthutm is practi- 

 cally similar to that of the palisade worm, except that, as far as 

 we know, it does not get into the arteries. The embryos enter 

 the horse's system by means of the water he drinks, or the damp 

 forage he eats, and having arrived in the caecum or large colon, 

 they burrow through the mucous membrajie of the intestine, a&d 

 each of them forms a cyst, in which it coils itself. It then under- 

 goes a stage of development, becomes mature, issues from its cyst, 

 attaches itself to the mucous membrane of the intestine (csecum or 

 large colon), and breeds; the eggs being carried out in the dung. 

 The worms do not come to puberty imtil Ahey leave their cysts. If 

 we open the csecum or large colon of a dead horse whicfi is infested 

 with these parasites, and scrape the mucous membrane of that 

 part, we shall see on its surface, sm.all dark spots, which indicate 

 the position of the oysts, and if we cut into one of them, we shall 

 find in it a coiled-up worm, which may be an embryo, or an adult 

 worm that is ready to quit its cyst and enter the intestine. The 

 foregoing account of the migrations of these parasites coincides 

 with that given by Neumann, Friedberger and Frohner, Cad6ac 

 and other authorities ; but some of the details of the subject have 

 not yet been definitely settled. 



" I have had cases of this form of helminthiasis brought under 

 my notice as early as December, but as a rule I think they are more 

 numerous during the months of January, February, and March. It 

 would seem that about this time the larvae, coiled up in the mucous 

 membrane of the csecum and large colon, are approaching maturity. 

 They have increased much in size, and many of them are preparing 

 to make a way through their epithelial covering, while some are 

 already free in the lumen of the bowel and have reached their full 

 development " (WilMe). 



The principal symptoms, aU of which are not necessarily present 

 at the same time, are as follows : — ^Dropsical swellings of the 

 lower surface of the belly, sheath and limbs ; pale condition of 

 the mucous membranes ; watery and more or less inflamed state 

 of the eyes ; bad smelling diarrhoea ; dulness ; debility ; emacia- 

 tion; staring coat; and the presence of the worm.s in the dung. 



26* 



