264 The Farmer's Veterinary Adviser. 



case of those beneath the jaws they fall into the food and 

 are devoured with it. By the aid of the hooks around 

 their heads they attach themselyes to the mucous mem- 

 brane mainly of the left liaK of the stomach but often also 

 of other parts such as the right side of the stomach, the 

 duodenum or small gut leading from the stomach, and the 

 throat. There they steadUy grow in the winter and in 

 spriQg pass out with the dung, burrow in the soil and are 

 transformed into the gadfly. The disturbance they cause 

 depends on their numbers and the portions of the canal 

 on which they attach themselves. In the throat they 

 produce a chronic sore-throat and discharge from the nose 

 which continues until the following spring, imless they are 

 previously extracted with the hand. In the left half of 

 the stomach which is covered with a thick insensible cuti- 

 cle they do little harm when in small numbers, hence 

 Bracy Clark supposed them to be rather beneficial in 

 stimulating the secretion of gastric juice. When very 

 numerous and above all when attached to the highly 

 sensitive right half of the stomach or the duodenum they 

 seriously interfere with digestion, causing the animals to 

 thrive badly, to be weak and easily sweated or fatigued, 

 and even determining sudden and fatal indigestions. This 

 last result is especially liable to occur in spring or early 

 summer, when the bots are passing out in great numbers 

 and hooking themselves at intervals to the coats of the 

 sensitive bowels in their course. They will sometimes 

 accumulate in such numbers as actually to block the pas- 

 sage. They even attach themselves to the skin outside 

 ihe anus causing the animal to go awkwardly, to switch his 

 tail and give other signs of extreme discomfort imtil the 

 tail is raised and the offender discovered and removed. 

 Alleged perforations of the stomach by bots are usually 

 ruptures, the result of indigestion. 



The irritation caused by their presence is not easily 

 distinguished from other forms of indigestion and colic. 

 It may be tympanitic or not, accompanied or not witlj 



