552 
The physical condition of the patient, the presence of associated 
disease, particularly of malaria, of the aneemias, and of other affections 
which are attended with intestinal autointoxication and with liver 
changes, naturally suggest themselves as predisposing factors, but definite 
and conclusive data are very difficult to obtain. 
There are also other influences which are not fully understood and 
which may play a part as predisposing factors. Among these we must 
not lose sight of the condition of and the changes in the liver itself 
previous to infection. It may be stated without going more fully into 
the subject at this time that cultural experiments with amcbe, now 
being carried on in this laboratory, indicate that amcebic abscess rarely 
or never develops in an otherwise normal liver, notwithstanding the 
fact that amcebe may be almost constantly poured into it from an 
ulcerated bowel. It has already been pointed out in a previous paper 
that rational treatment has brought about a great relative decrease in 
the frequency of liver abscess as a complication of the intestinal infection. 
The way in which amebe and bacteria reach the liver, and the man- 
ner of abscess formation have been a source of much discussion and 
are still in doubt. In the case of multiple abscesses, the evidence is 
fairly conclusive that the portal circulation acts as the means of trans- 
mission of the infection and indeed, no other explanation is at all sat- 
isfactory. No doubt this is also the principal channel by which the 
amoebe are transferred when a single abscess manifests itself, but | 
there are also valid reasons for believing that the latter are sometimes 
formed by the ameebe following directly continuous tissue. This view 
is strongly upheld by a number of careful observers who maintain 
that amoebae may even at times wander across the abdominal cavity and 
attack the liver at the apex of the dome. The rather frequent occurrence 
of subdiaphragmatic abscesses in places where the liver is not covered by 
its capsule is used as an argument in favor of this hypothesis. I have 
seen a few intestines in which the extensive ulcerations and adhesions 
about the hepatic flexure were so clearly associated with the abscess as to 
suggest direct infection. Other examples showing the disposition to 
wander which the organisms possess, are seen in the occasional ameebic 
pulmonary abscesses and empyemata which occur without liver abscess 
or other abdominal lesions. However, even after all these rarer occur- 
rences have been taken into account there still remains the great majority 
of abscesses the presence of which can only satisfactorily be explained by 
assuming the portal venous system to be the channel of transmission, and, 
when we consider the histologic findings which are derived from a 
study of the intestinal infection, it is surprising that liver abscesses are 
not more frequent. Ameebe, at times in great numbers, may frequently 
be seen in the blood vessels contiguous to the intestinal ulcers; in fact, 
where the lesions are extensive this may constantly be observed. These 
organisms may also be found in blood vessels in the intermuscular septa 
