While fording a shallow stream, the doctor's scraggy, ill-tempered horse took a fit of kicking quite frantical. For some time it seemed likely that either the doctor himself, or his saddle-bags, would be deposited in the bottom of the creek, but after a severe spell of whipping and kicking on the part of the rider, the animal moved on again. What had set it dancing? That was the question. It had the disposition to be "frisky," but usually appeared to be lacking in strength. The buzz of a horse-fly sounding in our ears explained all. It was one of those large insects--the "horse-bug,"--peculiar to the Mississippi country, and usually found near watercourses. They are more terrible to horses than a fierce dog would be. I have known horses gallop away from them as if pursued by a beast of prey. There is a belief among western people that these insects are propagated by the horses themselves; that is, that the eggs of the female are deposited upon the grass, so that the horses may swallow them; that incubation goes on within the stomach of the animal, and that the chrysalis is afterwards voided. I have met with others who believed in a still stranger theory; that the insect itself actually sought, and found, a passage into the stomach of the horse, some said by passing down his throat, others by boring a hole through his abdomen; and that in such cases the horse usually sickened, and was in danger of dying! After the doctor's mustang had returned to proper behaviour, these odd theories became the subject of discussion. The Kentuckian believed in them--the Englishman doubted them--the hunter-naturalist could not endorse them--and Besancon ignored them entirely. Shortly after the incident we entered the bottom lands of a considerable stream. These were heavily-timbered, and the shadow of the great forest trees afforded us a pleasant relief from the hot sun. Our guides told us we had several miles of such woods to pass through, and we were glad of the information. We noticed that most of the trees were beech, and their smooth straight trunks rose like columns around us.