THE ALIMENTARY TRACT 213 
Larger and more definitely obstructive physical 
objects are found in both mammals and birds. We have 
on record a lion (Felis leo) and a tiger {Felis tigris), 
which swallowed pieces of bone large enough to be stuck 
in the small intestine and completely occlude it. Smaller 
objects like buttons have been found even in the passerine 
tract. Worm masses may occupy such a large part of the 
lumen of the tube as to constitute a physical obstruction. 
This is definitely less important in mammals than in 
birds, especially in the passerine order of the latter class. 
Dilatation of the intestine aside from that occurring 
in connection with fermentation, constipation or ileus, in 
other words chronic atonic dilatation, has not been 
encountered. Acute dilatation has been found in several 
orders under the picture known for domesticated animals. 
Its pathology and incidence have already been discussed. 
Ileus. 
Ileus or acute intestinal obstruction may be divided 
for our purposes into intussusception, volvulus, strangu- 
lation and paralysis from interruption of mesenteric 
circulation. Examples of all these varieties have been 
encountered and illustrative cases will be cited. In so far 
as incidence is concerned, the Ungulata and Carnivora 
greatly outnumber all other orders, showing seven cases 
each ; the sum total in all other orders is but eight. Upon 
re-reading some of the protocols I have, however, 
excluded three invaginations in the carnivores, one each 
in the ungulates and rodents, as probably being post- 
mortem or shortly antemortem occurrences ; two had very 
early peritonitis but other things, sufficient to account for 
death, were present. These deductions bring the total 
cases of ileus in mammals to seventeen. Five cases in 
birds will be discussed briefly. 
Primates present one case of volvulus, one of intus- 
susception and one of internal strangulation. The first 
displayed the entrance of four inches of ileum into the 
