212 Veterinary Medicine. 



hatching may be effected in the intestine or in manure or water 

 external to the body. When hatched out in the intestine they 

 may pass out at once with the manure or they may envelop 

 themselves in pellets of the finer ingesta and remain for a time 

 in the bowel and finally pass out in this condition. Baillet has 

 traced their development out of the body. In a watery or damp 

 medium they are hatched out in a few days as a cylindroid . worm 

 }( to ys mm. long, thick in front and with a filiform tail. In 

 moist environment but especially in damp manure they grow to 

 I mm. or 1.5 mm. and continue for months iu this condition, but 

 remain small and asexual, until taken in, in the drink or green 

 food of the soliped. Reaching the inte.stiiie and especially the 

 caecum and colon they bore their way into the muco.sa and en- 

 cy.st themselves, or if they happen to perforate a blood-vessel 

 they make Vl habitat of that. In the cyst, development proceeds 

 and when it has reached a certain .stage the worm once more 

 bores its way through the mucosa and reaching the intestine be- 

 comes sexually mature. 



In this last migration the young worm is liable to perforate a 

 blood-ve.ssel in which case it is destined to a period of existence in 

 the blood. It may, however, have blundered upon a blood-vessel 

 at an earlier stage when seeking a temporary home in the mucous 

 membrane, so that the sclero.stomata of aneurisms may be derived 

 from two separate .sources. In the blood-vessels the parasite 

 attains a length of i to 8 lines, whereas in the mucous cysts it 

 does not exceed 3}^ lines. Yet Neumann holds that after leav- 

 ing the blood-vessels they may again ency.st themselves in the 

 mucosa before escaping into the intestine. 



Several moultings take place in the asexual condition. 



Other views have been advanced as to the development of the 

 sclerostomata. Colin believed that the ova depo.sited in the ducts 

 of the mucous glands and in the perforations made by the para- 

 site in blood-sucking, hatched in this .situation and the embryo 

 at once encysted itself in the mucosa. • 



l/cuckart imagines that the embryo found in the fseces or in 

 water outside the body of the soliped, should pass through an 

 intermediate host before it can return to gain sexual maturity in 

 the horse. But no evidence of the existence of such intermediate 

 host is furnished, and the encysted intestinal worms show no in- 



