IMPACTION OF THE CROP IN BIRDS. 
171 
stomach. Impaction results from excessive distension with dry foods, or 
with indigestible foreign bodies, and from compression of the oesophagus 
in diseases of the lungs. 
Symptoms comprise excessive fulness and distension of the crop, 
which feels hard and firm, want of appetite, and sometimes discharge of 
offensive fluid from the beak, which is usually held open. If the con¬ 
dition persists for long or frequently recurs, the crop becomes greatly 
dilated, the animals gradually waste, and may die. The condition is 
seen in fowls, ducks, geese, and pigeons and by recurrence becomes 
chronic. 
Treatment consists in massage. Attempts should be made to empty 
the crop or to break down the hardened contents by pressure and 
kneading. Ziirn recommends hydrochloric acid. If this proves useless, 
as in distention with foreign bodies like sand and stones, the crop must 
be emptied by operation, which is well sustained by most birds. After 
removing the feathers, the crop is divided in the long direction of the 
neck far enough to allow of the finger entering and the contents being 
withdrawn. The wound is cleansed and sutured, and generally heals by 
first intention. According to Ziirn pigeons are not good subjects foi 
operation, especially during breeding, the mucous membrane of the crop 
being swollen and very rich in blood-vessels. 
(2.) INJURIES TO THE PHARYNX AND (ESOPHAGUS 
((ESOPHAGEAL FISTULA). 
Injuries of the walls of the pharynx occur in all large animals, but most 
commonly in horses. When rasping the teeth the chisel or rasp, if caie- 
lessly handled, may severely injure the pharyngeal wall, and even produce 
death from bleeding or acute inflammatory processes. Like injuries 
result from the use of sticks in giving balls ; from awkward employment 
of pharyngeal sounds, forceps, and other instruments ; and in all 
animals, and notably in carnivora, from sharp foreign bodies. Merkl 
found a hairpin in a horse’s pharynx. Injuries to the oesophagus are 
almost invariably caused by sharp foreign bodies, or by oesophageal instill¬ 
ments used for their removal. Injuries from without are rare, though 
Graf and Braun have both seen injuries to the oesophagus in lioises 
caused by kicks from other animals. 
The course of such injuries depends entirely upon their character. As 
already stated, fatal bleeding may occur, or suffocation from passage of 
blood into the trachea. Where the inflammatory processes are super- 
ficial, and foreign bodies have been promptly removed, healing often 
occurs quickly; but deep-seated inflammation of the mucous membrane 
of the pharynx and adjacent parts may supervene (angina plilegmonosa), 
