ARTIFICIAL INFLAMMATION. 189 



387. Binlodlde of mercury in fulLstrtufjth. 



Biniodide of Mercuiy in full strength, i. e. 1 part of biniodide to 8 of 

 lard, commonly called " red ointment," is a vesicant. 



It is generally supposed to have a specific effect in exciting the action 

 of the absorbents, and is therefore frequently employed to assist nature 

 in the removal of osseous and other deposits. 



It is sharp in its action, but very irritating, especially to nervous and 

 high bred horses ; and for this reason should never be used if any fever 

 is present. But for the reduction of indolent swellings it is a valuable 

 remedy. 



It is also useful in some cases, where the preparations of Cantharides 

 are inadmissible on account of the facility with which the active prin- 

 ciple of the Spanish Fly is liable under certain circumstances (see pre- 

 ceding paragraph) to be absoi-bed into the system. 



388. Sdons. 



Setons in common with other in'itants produce hyperaemia in the parts 

 to which they are applied ; but the results arising from the hypersemia 

 are somewhat different from those caused by firing or blisters. Setons 

 act mainly on the deeper seated tissues, and produce their effects by 

 inducing the formation of pus from the lower layer of the skin rather 

 than mere vesication or effusion from the superficial blood-vessels. 



By this action they appear to have a powerful efi'ect both in promoting 

 the repair of the deeper seated tissues when injm-ed, and also in remov- 

 ing abnormal deposits. 



According to the nature of the material employed setons produce a 

 greater or less amount of irritation and suppuration. 



A silk thread for instance Avill cause but little irritation, whilst a horse- 

 hair tape will produce a violent effect. Further, a greater or less effect 

 may be induced according to the size and length of the seton, and the 

 amount of skin detached along its sides. The length will of course de- 

 pend on the extent, seat, and nature of the lesion. 



As compared with other agents, setons have in some cases the advan- 

 tage of exciting the hypersemia nearer to the seat of the disease, as for 

 instance in sprains of tendons, and moreover they may be left in for any 

 length of time, and consequently their action may be maintained as long 

 as necessary. These properties are of great value in the treatment of 

 disease or injury to tendons and other parts of low reparative power, and 

 also in some chronic affections. Setons if properly managed leave 

 scarcely any blemish. 



Their use, however, is attended with some inconveniences, which will 

 probably prevent their ever becoming a popular remedy. Their manao-e- 

 ment requires gi-eat care and attention from stable servants. The seton 

 should be pulled up and down every morning and evening. The matter 

 or pus, which collects in the channel, must on each occasion be 

 thoroughly and carefully pressed out along the whole length, by runnino- 



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