APPENDIX. 329 



feces in man, only one of which is pathogenic and the cause 

 of dysentery. Unfortunately the designation, amoeba coli, 

 has been applied to both species. The amoeba of dysentery 

 should be designated amoeba dysenteries, limiting the term 

 amoeba coli to the non-pathogenic form or forms. 



The amoeba dysenteric is a unicellular organism, 20-50 /* 

 in diameter when at rest, consisting of a clear, homogeneous 

 ectosarc and a granular endosarc, with an eccentrically 

 placed nucleus. The endosarc contains a number of vacu- 

 oles of variable size and very frequently red blood-cor- 

 puscles, as well as other foreign bodies such as bacteria, 

 pigment granules, etc. Many red blood-corpuscles may be 

 seen crowded together in a single amoeba. The organism is 

 actively amoeboid, extending its substance into processes 

 or pseudopodia of varying forms. This amoeboid motion 

 assists in making easy the recognition of the parasites under 

 the microscope and in distinguishing them from large, 

 swollen cells found in the feces. The stool should be ex- 

 amined while fresh and still warm. 



The non-pathogenic amoeba (amoeba coli), also occasion- 

 ally found in the intestinal tract of man, differs from the 

 pathogenic dysenteric organism chiefly in its much smaller 

 size ( 10-24 /;) and the invariable absence of red corpuscles 

 from its interior. The protoplasmic granules are also, as a 

 rule, smaller and are difficult to recognize. The amoeba 

 dysenteric produces experimentally definite ulceration of 

 the gut of cats, whereas the amoeba coli is harmless. Both 

 varieties of amoebae may be stained by a special stain de- 

 vised by Mallory. 2 



1 Strong, Circulars on Tropical Diseases, No. I, Chief Surgeon's 

 Office, Headquarters, Division of the Philippines, Manila, P. I., Feb- 

 ruary, 1901. Ibid., No. IT, April, 1901. (Both reports may be obtained 

 from the United States Government, Washington.) 



2 Mallory, Journal of Experimental Medicine, September, 1897, Vol. 

 II., p. 529. 



