FLAGELLATA 215 



differentiated by the fact that it is larger, coarser in structure, and 

 takes up red blood cells, which the former does not. Differentia- 

 tion by Wright's stain Entomcebacoli ectoplasm light blue, endoplasm 

 dark blue, nucleus red. Ent. histolytica ectoplasm dark blue, ento- 

 plasm light blue, nucleus pale red or pink. 



In stools (from dysenteric cases) over a day old, amoebae are not 

 often found, as they undergo a rapid disintegration outside the body. 



Amoebae are cultivated upon stiff agar in company with bacteria. 

 If a colony can be obtained free of bacteria, development will con- 

 tinue on agar smeared with organ extracts. The addition of dead 

 bacteria to culture media seems favorable to their development. 

 The poisin is not known. The free amoebae in the colon are easily 

 killed, but when encysted are more resistant. Quinine is fatal to 

 cultures in 10 minutes in strength of 1-2500. Formalin is not 

 practicable. 



The two varieties closely resembling Ent. histolytica are Entamceba 

 coll and Ent. tetragena. They vary in finer morphological details, 

 in their reproduction and their pathogenic properties. These two 

 varieties are not supposed to be pathogenic for man. According to 

 some authorities sulphur in some form is necessary for the growth of 

 amoebae. 



FLAGELLATA. 



The flagellata derive their name from the fact that all are pos- 

 sessed, at some time in their existence, of flagella, which are not only 

 organs of locomotion, but serve to apprehend 

 food. 



The principal members of this class of in- 

 terest from a pathological view-point, are the 



trypanosomes. Trypanosoma gambiense, FIG. 77. -Flagellata. 

 transmitted by the tsetse-fly Glossina palpalis * 



pathogenic for man (see page 218). The 



Trypanosoma brucei, which causes the tsetse-fly disease (nagana) 



in horses and cattle, is transmitted to cattle by the bite of the 



