122 



INTESTINAL FLAGELLATES AND CILIATES 



treatment the flagellates are said to decrease rapidly and to disap- 

 pear usually within a few days. Escomel, who has found Tri- 

 chomonas an important factor in diarrhea in Peru, advises an 

 enema consisting of one grain of iodine in a liter of water, taken 

 in the evening on three successful days. Unless the parasites 

 have established themselves in the membranes high up in the 

 intestine they are said to disappear after this treatment. As 

 with other intestinal Protozoa infection occurs through polluted 

 food or water. 



Macrostoma (or Tetramitus) mesnili. A parasite which 

 closely resembles Trichomonas in many respects is Macrostoma 

 mesnili (Fig. 32) . It is smaller than the former, averaging about 



FIG. 32. Macrostoma (or Tetramitus) mesnili; A, adult parasite (n., nucleus, 

 cyt., cytostome, 4th fl., fourth flagellum) ; B, end view of adult parasite, showing 

 cytostome with flagellum in it; C, degenerating form, resembling an ameba; D, 

 cyst, showing nucleus and cytostome. X 2000. (After Wenyon.) 



eight or ten /* (^W f an inch) in length. It has three slender 

 anterior flagella like Trichomonas but has no conspicuous undulat- 

 ing membrane. It has a large and conspicuous slit or cytostome 

 along one side which corresponds to the very small mouth cavity 

 of Trichomonas. Within the cytostome is a fourth inconspicu- 

 ous flagellum which seems to be attached to a small undulating 

 membrane. The posterior end of the body is drawn out into a 

 long point. As in Trichomonas the nucleus lies just behind the 

 origin of the flagella. The rest of the body contains numerous 

 vacuoles filled with bacteria, the latter apparently serving as 

 the staple article of diet. 



