640 APPENDIX. 
perience shows that the disease is not contagious, in 
the ordinary sense of the word, and that it is not 
directly transmitted from man to man. 
AMCBA COLI (Ameba Dysenterie of Councilman and 
Lafleur; Dysenteric Ameba). 
In 1875, Lésch, of St. Petersburg, gave the first 
accurate description of an amceboid organism which 
he found in the stools of a dysenteric patient, and to 
it he gave the name ameba coli. He claimed that this 
organism is the cause of dysentery, and he succeeded in 
producing a superficial ulceration of the large intestine 
in one of four dogs which had received rectal injec- 
tions of the dysenteric stools. Lésch’s observation 
has been confirmed by various researches in different 
countries. 
Morphology. The ameba is a unicellular organism 
belonging to the class of rhizopada of the protozoa, 
and consists of slightly differential masses of proto- 
plasm, which, under favorable circumstances, exhibits 
spontaneous movements. In a state of rest the amoeba 
assumes a spherical shape which appears discoid in the 
field of the microscope. It may generally be distin- 
guished from the other cellular elements found in the 
feces by its pale greenish tint and by its stronger 
refraction of light. Its diameter varies within wide 
limits, 6 to 354, more commonly between 12m and 
26y. It is noteworthy that such differences in size 
are found, as a rule, in different cases of the disease, 
while the amcebe in any individual case are nearly 
uniform in diameter. The body of a resting ameba 
has a well-defined, regular body, which, under ordi- 
nary conditions, appears as a thin, single, dark line. 
