214 



ANIMAL PARASITES 



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

 and white blood cells, bacteria, epithelial cells, and fecal 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 pseudopodia being withdrawn.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. Amceba dysenteriae is 

 always pathogenic. It is now considered 

 F IG> 75 . Amoeba dysen- the cause of the protozoal form of dysen- 

 teriae (Greene's Medical tery. So far as known this particular 

 Diagnosis.) 



variety exists only in the intestines of 



affected persons. Lesions similar to those of human dysentery have 

 been produced in monkeys, dogs and cats, and the amcebae recovered 

 from them. Cultures consisting only of amcebae have been ob- 

 tained by special technique, but a so-called pure mixed growth of 

 colon bacilli and amcebae is cultivated with little 

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

 dysentery cases, encysted amcebae are often 

 found. They have been seen in the liver (in 

 old cases), also in the lungs and sputum. In 

 over" 500 cases of dysentery the amoeba was 

 present in every instance. 



Cats have been infected by pus from liver JT IG 75. Ameboid 



abscesses devoid of bacteria (Kartulis). The motion. (Greene's 

 c .... , . , Medical Diagnosis.) 



unne, in cases of cystitis, contained amcebae, 



and it is believed to be the cause of the disease in. some rare 

 instances. In dysentery the amcebae "are the cause of the necrosis 

 and ulceration, as they frequently become encysted in the submu- 

 cous tissues. From the Entomceba colic the dysenteric amceba is 



