640 APPENDIX. 



perience shows that the disease is Dot contagious, in 

 the ordinary sense of the word, and that it is not 

 directly transmitted from man to man. 



AMCEBA COLI (Amoeba Dysenteriae of Councilman and 

 Lafleur; Dysenteric Amoeba). 



In 1875, Losch, of St. Petersburg, gave the first 

 accurate description of an amoeboid organism which 

 he found in the stools of a dysenteric patient, and to 

 it he gave the name amoeba 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. Losch' s observation 

 has been confirmed by various researches in different 

 countries. 



Morphology. The amoeba 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 35// 7 more commonly between 12// and 

 26//. It is noteworthy that such differences in size 

 are found, as a rule, in different cases of the disease, 

 while the amoebae in any individual case are nearly 

 uniform in diameter. The body of a resting amoeba 

 has a well-defined, regular body, which, under ordi- 

 nary conditions, appears as a thin, single, dark line. 



