PRINCIPLES OF VETERINARY SURGERY 373 



has reported cases of fistula in the dog due to punctures of 

 the toes either from thorns or spikelets of grass. 



SYMPTOMS. — The symptoms of fistula vary according 

 to the character of the integuments or organs affected. Sali- 

 vary, lachrymal, anal^ and rectovaginal fistula borrow a par- 

 ticular physiognomy from the products to which they give 

 issue. Some fistulae discharge pus or mucous, while othens 

 emit milk, urine or stercoral matter. All, however, exhibit 

 an orifice and a tract answering the following description : 

 The orifice is either projecting or depressed, and may by 

 virtue of its appearance be called "cul de poule." When 

 there are a number of openings it may be designated as a 

 "watering-pot" fistula. 



The tract may be simple or bifurcated, rectangular or sin- 

 uous, of small or great dimensions. The tissue surrounding 

 the tract is generally fibrous, lardaceous and resisting. The 

 discharges irritate the integument and cause a superficial 

 inflammation of the skin and loss of its hair. 



There is also more or less emaciation, due either to the 

 loss of some indispensable product, — saliva, gastric juice, 

 intestinal juice, etc. — or to the inexhaustible suppuration. 



PROGRESS. — As a general rule fistulse show no tend- 

 ency towards spontaneous recovery. Those which dis- 

 charge a glandular or organic product remain stationary for 

 an indefinite period. The persistence of fistulae is due in 

 some cases to infection; in others, the continuous flow of the 

 liquid secreted has a permanent irritating action, which is 

 further reinforced by a mechanical action resulting from the 

 shrinkage or closure of the tract and the formation of new 

 abscesses. Finally, others keep constantly extending until 

 some effective treatment is given to oppose the effect of the 

 pus in producing necrosis. 



PATHOLOGICAL ANATOMY.— Idiopathic fistulse— 

 those which follow abscesses, are nothing more than can- 



