32 02? SOUNDNESS. 



sid'ers that " in tbe majority of cases it is owing to dis- 

 ease of tbe great sciatic nerve, which governs the muscles 

 of the hind extremity ; nervous energy is tbus imperfectly 

 supplied, and, consequently, tbe more powerful muscles act 

 the most. It is often connected with disease of the hock, 

 and is sometimes preceded by it." 



Mr. Youatt says that " it rarely or never fails to deterio- 

 rate, and gradually wear out, the animal ; therefore, how- 

 ever stylish a rider may feel on his horse, with stringhalt 

 in both hind legs he must consider that he has an uusouud 

 horse." 



THICKENING or THE BACK SINEWS is to be considered 

 as unsoundness, as it is tbe result of a sprain or strain, 

 causing an inflammation and thickening ; the disease may 

 continue for months without any lameness, and with 

 nothing to draw attention to it. Mr. Walsh says, that in 

 thickening of tbe tendon or its sheath, however well the 

 animal might appear to be, yet " at length, an unusually 

 severe day's work sets up active inflammation, the leg 

 rapidly fills, and there is so much lameness as to cause the 

 horse to be thrown." 



Mr. Youatt says : " The continuance of any considerable 

 thickness around the sheaths of the tendons, indicates pre- 

 vious violent sprain. This very thickening will fetter the 

 action of the tendons, and, after much quick work, will 

 occasionally renew the inflammation and lameness ; there- 

 fore, such a horse cannot be sound." 



THOIIOUGHPIN is to be considered as unsouiidness, if of 

 an extensive size and causing lameness. On reference to 

 bog-spavin, the reader will find that all the arguments 

 used there are applicable to this disease. 



THRUSH is to be considered as unsoundness, as it is pro- 

 ductive of canker, which renders the animal totally unfit 



