DISEASES OF THE DIGESTIVE ORGANS. 171 



the heart for its place of abode; another inhabits the arteries; a 

 third, the kidney. 'Myriads of minute worms lie coiled up in the 

 voluntary muscles or in the areolar tissue that connects the flesh 

 fibers. The guinea-worm and chigoe bore through the skin, and 

 reside in the subajacent reticular membrane. Hydatids infest 

 various parts of the body, but especially the liver and brain. A 

 little fluke, in general appearance much like a minature flounder, 

 lives, steeped in gall, in the biliary vessels. If you squeeze from 

 the skin of your nose, what is vulgarly called a maggot (the contents 

 of one of the hair-pellicles), it is ten to one that you find in that 

 small sebaceous cylinder several animalcules, extremely minute, 

 yet exhibiting, under the microscope, a curious and complicated 

 structure. Even the eye has its living inmates; but it is in the 

 alimentary tube that we are most infested with these vermin." 



It is evident, from competent testimony, that these, as well as 

 other kinds of parasites, are always more or less injurious ; hence 

 the same may be true as regards the bot in a horse's stomach. The 

 best authority we have for the origin and history of the bot ia 

 Braoy Clark, V. S., a selection from whose works is here in- 

 troduced : 



"The (Estrus Equi, or the Stomach Bot. — "When the female has 

 been impregnated, and the eggs sufficiently matured, she seeks 

 among the horses a subject for her purpose ; and approaching him 

 on the wing, she carries her body nearly upright in the air, and 

 her tail, which is elevated or lengthened for the purpose, curved 

 inward and upward. In this way she approaches the part where 

 she designs to deposit the egg, and, suspending herself for a few 

 seconds before it, suddenly darts upon it, and leaves the egg ad- 

 hering to the hair. She hardly appears to settle, but merely 

 touches the hair, with the egg held out on the projected point of 

 the abdomen. The egg is made to adhere by means of a gluti- 

 nous liquor secreted with it. She then leaves the horse at a small 

 distance, and prepares a second egg, and, poising herself before the 

 part, deposits it in the same way. The liquor dries, and the egg 

 becomes firmly glued to the hair. This is repeated by these flies 

 till four or five hundred eggs are sometimes placed on one horse. 

 The skin of the horse is usually thrown into a tremulous motion 

 on the touch of this insect, which merely arises from the very great 

 irritability of the skin and cutaneous muscles at this season of the 

 year, occasioned by the heat and continual teasing cC the flies, till, 



