514 



DISEASES AND THEIR TREATMENT. 



884), but often also to other parts, such as the right side of the stomach, the duode- 

 num, or small gut leading from the stomach, and the throat. There they steadily 

 grow in the winter, and in spring pass out in 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, unless they are previously extracted with the hand. In the 

 left half of the stomach, which is covered with a thick, insensible cuticle, they do 

 little harm when in small numbers ; hence Bracy Clark supposed them to be benefi- 

 cial 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 animal 

 to thrive badly, to be weak, 

 and easily sweated or fatigued, 

 and even determining sudden 

 and fatal indigestion. This 



i w last result is especially liable 



I 4sHh£ IfA a t0 occur * n B P rm i? or early 



l ^^^p ^F\, summer, when the bots are 



_ j « JL passing out in great numbers, 



t / flH and hooking themselves at in- 



W fn mSk ^jEULf, JSH terva l s t0 tfl e coats of the sen- 

 ^ H SB ^r5Hrf^ WSB sitive bowels in their course. 

 fe« Sfflr Jmm\ ^^ They will sometimes accumu- 



late in such numbers as actu- 

 ally to block the passage. 



In discussing the sub- 

 ject, White says : — 



They are generally attached 

 to the cuticular or insensible 

 coat of the stomach ; but some- 

 times clusters of them are 

 found at the pylorus, and 

 even in the beginning of the first intestine, named the duodenum. In one case they 

 were so numerous in this last situation as to obstruct the passage completely, and 

 cause the animal's death. 



i Feron, an old writer, says he has paid particular attention to 

 this subject, and has found that when in large quantities, they are 

 very destructive to horses ; that he has seen several horses whose 

 stomachs had been pierced quite through by them, the bots making 

 their way into the abdomen. 



James Clark, of Edinburgh, an author of high standing, quoted 

 in " Shoeing," relates a case of a horse's stomach being perforated by 

 bots. 



Fig. 834.- 



-The Gadfly Depositing Eggs, and 

 Full-grown Bots. 



1. The female fly about to deposit an egg ; 2. the egg 

 magnified ; 3. the bot ; i. the eggs magnified, attached 

 to a hah- ; 5. the newly hatched bot ; 6. the bot full 

 grown ; 7. the head of a bot magnified ; 8. the male fly; 

 9. the chrysalis. 



