644 APPENDIX. 
Numerous investigations have demonstrated conclu- 
sively that amcebe may be present in the feces of 
healthy persons. They have also been found in cases 
of chronic diarrhcea, cholera, intestinal tuberculosis, 
typhoid fever, hemorrhoids, and other diseases; chiefly 
in such as are accompanied by looseness of the bowels. 
Some of the cases cited as chronic enteritis or chronic 
diarrhoea were in all probability examples of the more 
chronic form of ameebic dysentery, but not all of them, 
of course. Temporary looseness of the bowels in other- 
wise healthy persons, either as the result of slight indis- 
position or of medication, seems to be a condition of the 
presence of amcebe in the stools. Thus, Schulberg 
found these organisms in ten out of twenty loose stools 
produced by the administration of Carlsbad salts, and 
concluded that the amceba is a normal and harmless 
parasite of the intestines, the reason for its non-appear- 
ance in ordinary fecal evacuations being the solidity and 
acid reaction of the contents of the lower bowel, which 
soon destroy it. The question naturally arises whether 
more than one species of amceba is found in the human 
intestinal tract. So far no definite morphological dif- 
ferences have been found between the amoeba occurring 
in the stools of healthy persons and that in patients 
suffering from dysentery; nor can any deductions be 
drawn from the attempts to cultivate the amcba, for no 
one yet has succeeded in producing pure cultures of it. 
Pathogenesis. It is evident that, in the absence of 
artificially produced pure cultures of amcebe, inocula- 
tion experiments must be made wtih material such as 
dysenteric stools or the contents of hepatic abscesses. 
In a few cases such material from hepatic abscesses 
which was found to contain no organisms other than 
