264 PRINCIPLES OF VETERINARY SCIENCE 



prominence of the poll and down on to the forehead to insure 

 permanent relief. Injections of a specially prepared bacterin 

 have proved helpful in hastening recovery. 



FISTULOUS WITHERS 



Fistula of the withers is a disease similar to poll-evil, but is 

 located at the withers. It is commonly called "thistlelow." 

 Bruises have been thought to be the cause in many cases. In 

 view of the fact that pus is often present, even when there is no 

 evidence of a previous skin wound, it seems reasonable to 

 believe that the pus organisms must have been brought by the 

 blood. Unless the pus is evacuated it may burrow between 

 the muscles and break out on the shoulder. These fistulse may 

 be very slow in forming. A deep-seated abscess cavity of many 

 months' standing with no external signs of its presence has been 

 found in a horse in the dissecting laboratory. The chief symptom 

 is a hot, painful swelling which appears on one or both sides of 

 the dorsal vertebrae at the withers. A surgical operation to allow 

 the accumulated pus to escape, and to remove thickened 

 tissue and necrosed bone, is the only treatment recommended for 

 permanent relief. Caustic applications to destroy the diseased 

 tissues should be used only on the advice of the attending veteri- 

 narian. In most cases success follows proper surgical treatment, 

 but only after several weeks. If the animal has little value, it 

 will be well carefully to consider the advisability of going to the ex- 

 pense in loss of time and the feed required before he would be 

 fit for return to service. 



SHOE BOIL 



Shoe boil is a soft, flabby swelling that develops at the point 

 of the elbow, hence the name "capped elbow." Chief among 

 the causes of this disease is pressure from the heel calk of the 

 shoe. As a rule, it results in lameness only when acute inflamma- 

 tion is present, and when its size interferes with movement. 

 At best a shoe boil is unsatisfactory to treat. If discovered 

 while yet small, it may be prevented from further development 

 by daily applications of tincture of iodin and the use of the shoe- 

 boil boot or roll, which is designed to be strapped about the 

 pastern to keep the heel from pressing upon the elbow while the 



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