246 DISEASE IN WILD MAMMALS AND BIRDS 
the cleft between the limbs of the duodenal loop, and it 
discharges its secretion into the duodenum by two or 
three ducts separately, and almost invariably above the 
bile duct openings. One duct always opens near the top 
of the distal end of the duodenal loop, near the bile duct. 
In the gallinaceous birds that have a bile duct opening 
into the duodenum near the pylorus, there is usually a 
pancreatic duct opening there also. In some birds a third 
duct passes from the body of the pancreas to the duo- 
denum at different places along the loop. It does not 
seem probable that dislocation of the duodenal loop would 
seriously interfere with the passage of the pancreatic 
secretions, since the gland is so intimately related with 
the duodenal serosa, but obstruction to the biliary flow 
due to changes in position of the intestine is easier 
because the bile duct is separate and loose and arises 
from the end of the gall-bladder. The ducts of both these 
structures pass very obliquely through the duodenal wall 
a matter of importance, as will be seen when discussing 
the infiltrative forms of enteritis. The gall-bladder is 
not present in all birds, but this is probably of no 
importance, as the hepatic ducts are wide and run 
directly from the liver to the duodenum. The pancreatic 
ducts are short and are closely bound around by glandu- 
lar tissue up to a place quite close to their entrance into 
the intestine. 
The musculature of the gall-bladder and the ducts 
seems comparable in mammals and birds, and a con- 
strictor or sphincter usually called the muscle of Oddi, 
is present in all but pigeons (Oddi). There may be found 
also muscular fibres in the major ducts of the pancreas, 
but they are not so heavy nor distributed so definitely as 
similar tissue in the bile duct walls. The mucosa of 
the pancreatic duct is much more folded in birds than in 
mammals, seemingly, therefore, more adapted to obstruc- 
tion by swelling from any cause. 
