202 THE HORSE. 



considerable size, d, and being destined to undergo a certain transformation, 

 it disengages itself from the cuticular coat, is carried into the villous portion 

 of the stomach with the food, passes out of it with the chyme, and is fuiallv 

 evacuated with the dung. 



The larva or maggot being thus thrown out, seeks shelter in the ground, 

 contracts in size, and becomes a chrysalis or grub ; in which state it lies 

 inactive for a few weeks; and then, bursting from its confinement, assumes 

 the form of a fly. The female, becoming impregnated, quickly deposits her 

 eggs on those parts of the horse which he is most likely to lick, and so the 

 species is perpetuated. 



There are several plain conclusions from this history. The bots cannot, 

 while they inhabit the stomach of the horse, give the animal any pain, for 

 they are fastened on the cuticular or insensible coat. They cannot stimu- 

 late the stomach, and increase its digestive power, for they are not on the 

 digestive portion of the stomach. They cannot, by their roughness, assist 

 the trituration or rubbing down of the food, for no such office is performed 

 in that part of the stomach : the food is softened, not rubbed down. They 

 cannot be injurious to the horse, for he enjoys the most perfect health 

 when the cuticular part of his stomach is filled with them, and their pres- 

 ence is not even suspected until they appear at the anus. . They cannot 

 be removed by medicine, because they are not in that part of the stomach 

 to which medicine is usually conveyed ; and if they were, their mouths are 

 too deeply buried in the mucus for any medicine, that can safely be admin- 

 istered, to affect them; and, last of all, in due course of time, they detach 

 themselves, and come away. Therefore, the wise man will leave them to 

 themselves, or content himself with picking them off when they collect 

 under the tail, and annoy the animal. 



The smaller hot, f and g, is not so frequently found. 



INTESTINES. 



The food having been partially digested in the stomach, and converted 

 into chyme, passes through the pyloric orifice into the intestines. 



The intestines of a full-grown horse are not less than ninety feet in 

 length. The length of the intestines, in different animals, depends on the 

 nature of the food. The nutritive matter is with much more difficulty 

 extracted from vegetable than animal substances ; therefore the alimentary 

 canal is large, long, and complicated in those which, like the horse, are fed 

 on herbs alone. They are divided into the small and large intestines; the 

 former of which occupy about sixty-six feet, and the latter about twenty- 

 four. The intestines, like the stomach, are composed of three coats. The 

 outer one consists of the peritoneum, that membrane which we have already 

 described as covering the contents of the belly. By means of this coat the 

 bowels are confined in their proper situations; and, this membrane being 

 smooth and moist, all friction and concussion are avoided. Did the bowels 

 float loosely in the belly, they would be subject to constant entanglement 

 and injury amid the rapid and violent motions of the horse. 



The middle coat, like that of the stomach, is muscular, and composed of 

 two layers of fibres — one running longitudinally and the other circularly; 

 and by means of these muscles, which are continually contracting and relax- 

 ing, from the upper part downward, the food is forced along the bowels. 

 The inner coat is the mucous or villous: mucous because it abounds with 

 small glands, which pour out a mucous fluid, to lubricate the passage and 

 defend it from irritating or acrimonious substances; and villous, from it* 



