332 EUllEAU VF ANIMAL INDUSTRY. 



product of secretion from one tendinous synovial and several articular 

 synovial sacs. A large articular sac contributes to the lubrication of 

 the shank bone (the tibia) and one of the bones of the hock (the astra- 

 galus). The tendinous sac lies back of the articulation itself and 

 extends upward and downward in the groove of that joint through 

 which the flexor tendons slide. The dilatation of this articular S3"no- 

 vial sac is what is denominated bog spavin, the term thoroughpin being 

 applied to the dilatation of the tendinous capsule. 



The bog spavin is a round, smooth, well-defined, fluctuating tumor 

 situated in front and a little inward of the hock. On pressure it 

 disappears at this point to reappear on the outside and just behind the 

 hock. If pressed to the front from the outside it will then appear 

 on the inside of the hock. On its outer surface it presents a vein 

 which is quite prominent, running from below upward, and it is to 

 the preternatural dilatation of this blood vessel that tlic term blood 

 spavin is applied. 



The thoroughpin is found at the back and on the top of the hock 

 in that part known as the "hollows," immediately behind the shank 

 bone. It is round and smooth, but not so regularly formed as the 

 bog spavin, and is most apparent when viewed from behind. The 

 swelling is usually on both sides and a little in front of the so-called 

 hamstring, but may be more noticeable on the inside or on the outside. 



In their general characteristics bog spavins and thoroughpins are 

 similar to windgalls, and one description of the origin, symptoms, 

 pathological changes, and treatment will serve for all equally, except 

 that it is possible for a bog spavin to cause lameness, and thus to 

 involve a verdict of unsoundness in the patient, a circumstance which 

 will, of course, justify its classification b}' itself as a severer fornfof a 

 single type of disease. 



We have already referred to the subject of treatment and the means 

 employed — 7'est, of course — with liniments, blisters, etc, and what we 

 esteem as the most active and beneficial of any, earlij, deep^ and well- 

 jperforined cauterhat'wn. There are, besides, commendatory reports 

 of a form of treatment by the application of pressure pads and pecul- 

 iar bandages upon the hocks, and it is claimed that the removal of the 

 tumors has been effected b}- their use. But our experience with this 

 apparatus has not been accompanied by such favorable results as would 

 justify our indorsement of the flattering representations which have 

 sometimes appeared in its behalf. 



OPEN JOINTS, BROKEN KNEES, SYNOVITIS, AND ARTHRITIS. 



The close relationship which exists among these several afi'cctions, 

 their apparcntlj'' possible connection as successive developments of a 

 similar, if not an essentially identical, origin, together with the advan- 

 tage gained by avoiding frequent repetitions in the details of symp- 



