912 DISEASES AND THEIR TREATMENT. 



after either of these medicmes. Nearly all parasites in horses 

 . can be expelled by the judicious use of calomel. 



BOTS. 



As among most owners and horse-doctors, cvt^ry obscure lame- 

 ness in the foot is- supposed to be in the shoulder; so, when a horse 

 is taken sick, nine times out of ten it is supposed to be caused by 

 bots. If the horse turns up his upper lip, looks at his side, shoAA's 

 uneasiness, paws, and rolls, it is taken as a sure sign of bots. 



It is claimed that as a rule bots are harmless parasites, seldom 

 producing much mischief, and to be found in almost every hor.se 

 that dies, sometimes in great numbers, adhering to the coats of 

 the stomach ; but about this there is much difference of opinion. 



Prof. Law on the subject: — 



'■ Bots urc the larva of the gadjly, which are iioticed i;> be so 

 common, jjestcring the horse during the summer and autumn, darl- 

 ing at him around his legs and sides, and depositing their eggs on 

 the hair of the parts. These eggs are caught by the*horse when 

 he licks the jJ'^^i'ts in defending himself, and SAvallowed. In the 

 stomach they develop rapidly. By the aid of the hooks around 

 their heads they attach themselves to the mucous membrane mainl}' 

 of the left half of the stomach (Sec Fig. 800), but often also to other 

 parts, such as the right side of the stomach, the duodenum or small 

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

 grow in the winter, and in spring ])ass 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 

 Avhich they attach themselves. In the throat they produce a 

 chronic sore throat and discharge from the nose, Avhich continues 

 until the following spring, xmless they are previousl}" extracted 

 Avith the hand. In the left half of the stomach, A\'hich is covered 

 with a thick, insensible cuticle, they do little harm Avhen in small 

 numbers; hence Bracy Clark supj^osed 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 Avith digestion, causing the animals to thriA-e 

 badly, to be weak, and easily SAveated or fatigued, and even detei*- 

 mining sudden and fatal indigestions. This last result is especially 

 liable to occur in spring or eai'ly summer, when the bots are pass- 

 ing out in great numbers, and hooking themselves at intervals to 

 the coats of the sensitive bowels in their course. They Avill some- 

 times accumulate in such numbers as actually to block the pas- 

 sage." 



