PRINCIPLES OF VETERINARY SURGERY 361 



PROGRESS. — As a rule chronic abscesses have a ten- 

 dency to remain stationary. In exceptional cases inflamma- 

 tion may be aroused and the abscess transformed into a hot 

 abscess. 



DIAGNOSIS. — Chronic abscess of the neck and shoul- 

 der may be confounded with fibroma or melanosis. The 

 seat may, however, lead to a diagnosis. The existence of a 

 tumor more or less fibrous in front of the shoulder, for ex- 

 ample, would at once suggest itself as a cold abscess. The 

 dififerentiation is based upon the perfect delimitation and the 

 absokite mobility of the skin if the case is one of neoplasm. 

 If. on the contrai"y, the case is one of cold abscess, the re- 

 gion will not be absolutely free from swelling and the skin 

 will be more or less adherent and thickened. Fibrous tu- 

 mors associated with botryomyces always expose to view a 

 fistula which discharges a purulent product rich in parasites. 



PROGNOSIS. — Chronic abscesses are always graver 

 than the hot ones on account of the slowness of their evo- 

 lution, the nature of the causes which govern their develop- 

 ment ,and the difficulty which is often found to make them 

 disappear. When they make their appearance after the nec- 

 rosis or caries of a cartilage or ligament (fistula of the with- 

 ers, poll-evil, quittor, etc.) they still further complicate mat- 

 ters. 



PATHOLOGICAL ANATOMY.— The hard variety are 

 composed of a fibrous wall, sometimes very thick and ad- 

 herent to the skin, which is generally thickened, infiltrated 

 and hardened over a considerable area. It is unusual to see 

 the wall of the abscess adhere to or become mixed up with 

 muscular tissue, as the latter will be found to have undergone 

 fibrous degeneration. On being cut the hard abscess re- 

 veals one or more cavities of very limited dimensions,- con- 

 taining a thick, greasy pus that is subject to calcareous in- 

 filtration when the lesion is of long standing. 



