300 Mr. ClarkV OhferviU'ions m the Gmus Oejlrus. 



The flownefs of their growth and the purity of their food mufl: 

 occafion what they receive in a given time to be proportionai)Iy 

 ftnall; from whence probably arifcs the extreme difficLilty there is 

 found in deftroying them by any medicine or poifon thrown into 

 the flomach. After opium had been adminiftered to ahorfe labour- 

 ing under a cafe of locked jaw for a week, in dofcs of one ounce 

 every day, on the death of the animal I have found the bots in the 

 ftomach perfeftly alive. Tobacco has been employed in much 

 larger quantities in the fame complaint, and has been alfo longer 

 continued without deftroying them. They are alfo but rarely af- 

 fedled by the draflic purgatives which bring away in abundance the 

 1'etiice and Afcaridcs. 



I do not apprehend they are fo \'ery injurious to the horfcs as is 

 generally conceived. When removed from the flomach a deep im- 

 prefllon remains where they adhered ; but whether they ever irritate 

 it fo as to bring on a fatal fpafm of the flomach itfclf, or of the 

 pylorus, or, by collecting round this paffage, prevent the food from 

 entering the intefline, has, I believe, never been inveftigated with 

 fufficient accuracy. The ignorant furprife of farriers on opening 

 the flomach after death, and- being prefented with fo fingular an 

 appearance as the bots, has, without doubt, very often occafioned the 

 death to be attributed to thefe, though it is certain but few horfes on 

 our commons can efcape them. At the extremity of the truncated 

 end are feen two protuberant kind of lips, applied to each other. See 

 fig. 7, a. When thefe unfold, or are removed with the knife, a plate 

 of horny or cartilaginous confiflence is feen, having fix femicircular 

 lines, with their points oppofed to each other. See fig. 23. Thefe 

 lines are rough, and made up of alternate deprefTed and elevated 

 fpots of black and white. 



Through this plate the airis admitted to fill the air tubes; andia 



moft 



