AMCEBA DYSENTERIC 235 



but not in the round quiescent cell. In the endosarc, which is 

 granular, vacuoles are easily seen; so are fragments of food, red 

 and white blood cells, bacteria, eipthelial cells, and faecal matter. 

 The pseudopodia are broad and lobose; one or two are protruded 

 at a time. The motion of the organism depends upon the reaction 

 of the media, and the temperature. The vacuoles and nucleus 

 are always present. Propagation generally takes place by binary 

 division, the process beginning in the nucleus. When irritated, 

 the amoeba at once assumes a spherical form, the pseudopodia 

 being withdrawn. 



Pathogenesis. Amoeba dysenteriae is the cause of the protozoal 

 form of dysentery. So far as known this particular variety exists 

 only in the intestines of effected persons. Lesions similar to those 

 of human dysentery have been produced in monkeys, dogs and 

 cats, and the amoebae recovered from them. Cultures consisting 

 only of amoebae have been obtained by special technique, but a so- 

 called pure mixed growth of colon bacilli and amoebae is cultivated 

 with little difficulty. In the lower gut of man and cats, in 

 dysentery cases, encysted amoebae are often found. They have 

 been seen in the liver (in old cases), also in the lungs and sputum. 



Cats have been infected by pus from liver abscessed devoid of 

 bacteria (Kartulis). The urine, in cases of cystitis, contained 

 amoebae, and it is believed to be the cause of the disease in some 

 rare instances. In dysentery the amoebae are the cause of the 

 necrosis and ulceration, as they frequently become encysted in 

 the submucous tissues. From the Entamceba coli the dysenteric 

 amoebae is differentiated by the fact that it is larger, coarser in 

 structure, and takes up red blood cells, which the former does 

 not. Differentiation by Wright's stain Entamceba coli ectoplasm 

 light blue, endoplasm dark blue, nucleus red. Ent. histolytica 

 ectoplasm dark blue, entoplasm light blue, nucleus pale red or 

 pink. 



Amoebae quickly loose their mobility as the surrounding tem- 

 perature leaves that of the normal body, although they are not 



