360 PRINCIPLES OF VETERINARY SURGERY 



collections may be the work of the pyogenic micro-organ- 

 isms, — staphylococcus, pyogenes albus and aureus, strep- 

 tococcus pyogenes, pneumococcus, etc. In domestic ani- 

 mals chronic abscesses are likewise provoked by the inoc- 

 ulation of the micro-organisms of suppuration. Bossi has 

 stated that in abscesses of the shoulders there are special 

 micro-organisms which may exhibit particular cjualities, but 

 which may have only a moderate degree of virulence. In 

 reality, however, these agents belong to the pyogenic mi- 

 cro-organisms. 



In our bacteriological examination of the microbian flora 

 of cold abscesses we have found that in every case the or- 

 ganisms were those of ■suppuration, notably streptococci and 

 rarely staphylococci. 



Their introduction into the subcutem occurs through 

 excoriation of the skin, or through the medium of the cuta- 

 neous glands or hair follicles. Their propagation through 

 the blood channel is exceptional. 



SYMPTOMS.— Hard Abscesses.— These pus collections 

 are characterized by a more or less voluminous and diffused 

 tumefaction, without any clearly marked acute features. 

 Sometimes they are accompanied by a light "edematous 

 cloud.'" They are not hot, slightly or not at all painful, and 

 the skin is only feebly attached to their surface. Finally they 

 develop the characteristics of genuine fibrous tumors, and 

 fluctuation is scarcely ever a perceptible feature. When 

 located in the mastoido-humeralis, at the base of the neck 

 and shoulders, they render the animal unfit for service by 

 the permanent pain produced by the pressure of the collar. 



Soft Abscesses. — Soft abscesses present the physiognomy 

 of cysts, and are uniformly fluctuating Avithout inflammatory 

 characteristics. They may, however, display a slight pe- 

 ripheric cedema, and may be the seat of a rather keen sensi- 

 bility. They are nearly always abscesses from congestion. 



