THE ALIMENTARY TRACT 181 
physically obstruct the lumen and lead to intestinal stasis 
and dilatation. 
Inflammation. 
In analyzing the cause of a gastroenteritis and its 
consequent effect upon the wall of the tube and upon the 
viscera, certain physical, chemical and physiological fac- 
tors must be considered. Whether this may be directly 
the effect of bacteria or poisons from worms or some 
other factor seems of little moment since in any fully 
developed case, symptoms and effects are comparable. 
Moreover it seems that pathological anatomy, both gross 
and minute, is essentially the same from Primates to 
struthious birds, the highest and lowest of the two classes 
here considered. By this is meant that the acute con- 
gestive condition of the gut tract with solution of the 
surface, to which we have applied the name of toxic 
enteritis, seems to be met with in this form throughout 
all the orders. So too catarrhal inflammations are the 
same to the naked eye and under the microscope, due 
allowance being made for the fact that mammals use poly- 
nuclear cells for exudative purposes while birds employ 
mononuclears. Concomitantly with these conditions, a 
degenerative process may be going on in the liver and 
kidney, and hyperplasias, especially in the true infec- 
tive processes, will be found in the related lym- 
phatic structures. 
The majority of students today place responsibility 
for gastroenteritis upon the bacteria known to be present 
in the various intestinal tracts, mentioning especially 
colon and proteus groups, streptococci, the necrosis bacil- 
lus and anaerobes of the Welch class. In a few of our 
studies of intestinal bacteria in cases of enteritis one thing 
has been very definite and that is that in the intestinal 
content of animals whose food is largely meat. Gram-nega- 
tive bacilli have predominated, whereas in herbivorous 
animals Gram-positive organisms have been most numer- 
