334 SALIVARY FISTULiE. 



through inflammatory processes, and that the duct itself afterwards 

 atrophied. Even this method, however, sometimes fails. 



Harms very appropriately points out that experiments, although 

 successful on healthy horses, do not demonstrate the efficacy of similar 

 treatment in diseased ones. Reynal found that it was not always possible 

 to produce adhesion of the duct by section. The fact must not be lost 

 sight of that in fistula of the salivary duct the opening of the duct into 

 the mouth is generally occluded. Permanent closure of the duct gradually 

 leads to atrophy of the parotid. Moller saw a horse in which the right 

 Stenson's duct was dilated to the thickness of a man's thumb, and was 

 without opening into the mouth. The gland had entirely disappeared, 

 and the parotid region presented a marked depression. 



(3) Injection of irritant fluids into the gland. Haubner recom- 

 mended liquor amm. caust. 10 to 15 per cent. Tincture of iodine, 

 creosote, nitrate of silver, &c, have since been used. Bassi injected 

 30 per cent, of alcohol ; Labat the following mixture, — 20 to 40 

 per cent, of tincture of iodine, 1 per cent, iodide of potassium, and 

 60 per cent, of water ; Delamotte, 50 per cent, tincture of iodine ; 

 Bergeron, a 20 per cent, solution of lactic acid. Concentrated tincture 

 of iodine usually produces severe inflammation of the gland, some- 

 times ending in necrosis, and therefore diluted solution of iodine in 

 iodide of potassium is to be preferred. The injection can be repeated 

 if necessary. Abscesses often result, but in no way interfere with 

 success. 



(4) Extirpation of the parotid gland is effectual, but the operation 

 is difficult and not free from danger. The horse, cast on the opposite 

 side, is anaesthetised, and the head and upper portion of the neck 

 are placed on a cushion so as to increase the prominence of the 

 operation field, which is washed, shaved and disinfected. The skin 

 and parotido-auricularis muscle are incised in the middle line from 

 the base of the ear to below the glosso-facial vein ; and the edges 

 of the skin are detached from the parotid in front and behind and at 

 both extremities of the incision. To avoid injury to the numerous 

 important blood-vessels and nerves, the operation should be continued 

 by blunt dissection, employing the fingers, spatula, or closed scissors. 

 Degive advises beginning at the upper extremity of the wound by 

 ligaturing and dividing the posterior auricular vein ; then detaching 

 the anterior border of the gland from above to below, and isolating 

 the jugular vein from its connection with the parotid. Next dividing 

 the gland into two parts : an inferior which is detached from above 

 to below, and a superior which is dissected from below to above, 

 proceeding carefully in order to avoid damaging the external carotid 

 artery, its two terminal branches (external maxillary and temporal), 



