PATHOGENIC PROTOZOA OF THE CLASS SAKCODINA 419 



plasm is finely granular, and rarely contains more than a single 

 vacuole. The nucleus is definite, spherical, and contains chroma- 

 tin granules and one or more nucleoli; it is 5 to 8 ft in diameter. 

 When stained by Wright's method, the ectoplasm and endoplasm 

 may be easily differentiated. The ectoplasm stains blue, the 

 endoplasm violet, and the nucleus red. 



Multiplication is commonly accomplished in the intestines 

 by simple division. The nucleus divides and the protoplasm con- 

 stricts to form two individuals. This process is common in the 

 liquid stools, but, when drier and firmer, cystic reproduction is 

 more common. A refractive hyaline cyst forms about the spher- 

 ical organism, and thickens. The protoplasm becomes homo- 

 geneous in appearance and clearer than before. The nucleus then 

 undergoes complicated divisions and recombinations, which ul- 

 timately result in the formation of eight nuclei. When the wall 

 is ruptured these nuclei, with bits of the protoplasm, escape and 

 constitute eight young amebse. 



Pathogenesis. Repeated efforts to produce disease by injec- 

 tion of Entamceba coli into the colon of cats and other animals have 

 failed. It must be regarded as a normal inhabitant of the intes- 

 tines of man. Similar organisms have been found in the intes- 

 tines of animals. 



Bacteriological Diagnosis. Entamceba coli may be recognized 

 in the feces by a direct microscopic examination as an ameba 

 showing very slight motility, rounded pseudopodia, little or no 

 observable differentiation between ectoplasm and endoplasm, 

 comparative lack of vacuoles in protoplasm, and by the production 

 of eight daughter-cells from each cyst. 



Entamceba histolytica 



Synonym. Amoeba dysenteries. 



Disease Produced. Amebic dysentery in man. 



Loesch, in 1875, described Amoeba coli as the cause of a dysen- 

 tery in man, and claimed that the rectal injection of feces con- 

 taining the organisms into dogs produced dysentery. Robert 

 Koch, in 1883, showed the organism to be present in the ulcerations 

 of the intestines. Kartulis firmly established a probable etio- 

 logical relationship by his studies in Egypt, published in 1886. 



