Gastric Parasites in the Horse. 251 



orifice in front of median part of the body. Ova almost linear 

 with the embryo folded double. Viviparous. 



Lesions. These worms burrow, hollowing out galleries and 

 passages between the mucosa and muscular coat, and determine 

 the formation of tumors varying in size from a hazel nut to a 

 hen's egg. The galleries communicate with the stomach by 

 small orifices varying in number from one to five or six. The 

 worms are found in the galleries and may be pressed out by 

 squeezing the tumor. Sometimes the contents consolidate giving 

 the tumor a feeling of great firmness. In some instances there 

 are found debris of the worms and purulent contents. 



Pathogenesis. These are generally held to be harmless even 

 when present in large numbers. This is hardly compatible with 

 the extensive changes observed in the gastric mucosa, and more 

 probably they cause impaired digestion, the true cause of which 

 cannot be diagno.sed. Railliet justly observes that the formation 

 of tumors in or near the pylorous may hinder the passage of 

 ingesta. 



Spiroptera Microstoma. This is larger than the megas- 

 tonia the male being 5 to 7 lines in length, and the female i inch. 

 It lacks the cervical constriction, and has only two oral papillae. 

 It is viviparous. 



This worm is found free in the liquid contents of the stomach, 

 and just after death when still warm the fluid shows undulatory 

 or boiling motion from the active swimming movements of the 

 parasite. When cold, they are still and are usually overlooked, 

 on account of their small size. When the contents are firm or 

 fibrous they must be looked for with great care. The parasite is 

 often found with its head engaged in one of the mucous glands 

 of the right sac, and in other cases its presence has been asso- 

 ciated with extensive ulcers of the mucosa in this sac. 



Pathogenesis and Symptoms. Apart from the lesions found 

 postmortem, no characteristic symptom or result of these para- 

 sites has been observed. At the same time it is certain that such 

 ulcerations as have been found, must cause more or less gastric 

 indigestion, and loss of condition, even though acute colic may be 

 escaped. 



Treatment of Spiroptera. This is essentially the same as for 

 other parasites of the digestive organs. As the symptoms can 



