PRINCIPLES OF VETERINARY SURGERY 359 



Chronic abscesses are characterized by the slowness of 

 their development and the mildness of the inflammatory phe- 

 nomena of which, they are the seat. They are divded, like 

 hot abscesses, into idiopathic and symptomatic. In the latter 

 category are included local symptomatic abscesses which de- 

 velop in the neighborhood of the afifection by which they are 

 generated, and of which suppurative phlebitis is an example. 

 In this group is likewise included abscess from congestion, 

 an example of which are the abscesses that occur in the 

 shoulder as a sequel to an afifection of the withers; lymphatic 

 abscesses that have their seat in a gland; and finally abscesses 

 (the term beino' descriptive of a general malady) of stran- 

 gles, glanders, tuberculosis, etc. 



From a clinical point of view these distinctions are not 



important, cold abscesses being classified for this purpose, 



according to their consistency, into hard and soft abscesses. 



FREQUENCY. — Chronic abscesses are frequent in the 



horse, the ox and the dog. 



ETIOLOGY. — Hard chronic abscesses occur in the 

 horse as the sequel of repeated contusions. Contact of the 

 harness in certain regions, at the neck, withers and the point 

 of the shoulder is the principal contributing cause. They 

 are also produced in the limbs by "interfering" and on the 

 projecting points of the body from the decumbency of dis- 

 eases. Frequently they result in necrosis or caries, and are 

 often observed among debilitated animals exhausted by hard 

 woi-k or by a previous pathological state. 



In the ox the greatest number of cold abscesses arise 

 from the passage of a foreign body through the tissues, after 

 an acute abscess has inoculated the neighboring regions. 



PATHOGENESIS. — Not long ago it was supposed that 

 all cold abscesses in man were of tuberculous origin, but the 

 recent researches of Mauclaire, Bertoye, Roger, Arloing, 

 Achalne and Conamin have demonstrated that these pus 



