PART II. CHARACTERS AND DIAGNOSIS 79 



(13) Course of Tetramitus Infections. 



On account of the characteristic cysts it is much easier to 

 control a tetramitus infection than one of trichomonas. On those 

 occasions when the flagellates are absent from a formed stool their 

 presence in the gut is still detected by the pear-shaped cysts which 

 escape in the fasces. Though, like trichomonas, tetramitus tends 

 to be present intermittently in the stool, this feature is not nearly 

 so marked. In case Howard, for instance, the flagellate was present 

 practically continuously for over fifty days. In another case, 

 Gildel, it was present for ninety-one days, being absent only for 

 about a month at the middle of the observation owing to treatment 

 by emetin orally administered. A glance through the cases of 

 E. histolytica infections illustrated in the tables at the end of this 

 paper will show how the tetramitus infection persists, and though 

 it may disappear for a time it reappears again later. As such an 

 infection can persist for over three months it must do so for longer 

 periods, though we have not the same data as we have in the case 

 of the lamblia infections, which one of us (C. M. W.) has already 

 shown to be able to persist in the intestine for several years. 



(14) Trichomonas intestinalis and Trichomonas in the Mouth. 

 (Plate III, figs. 18 to 23.) * 



The general structure of this flagellate has already been described 

 by many observers, and it has been pointed out that the number 

 of flagella is either three (trichomonas), four (tetratrichomonas), 

 or five (pentatrichomonas). The commonest type seen by us has 

 been the tetratrichomonas (Plate III, figs. 19 to 23),* though three 

 and five-flagellar forms (Plate III, fig. 18)* have been seen, each 

 on one occasion. Apart from the flagella the three types show no 

 variations in structure, though a peculiar difficulty in the making 

 of satisfactorily stained films of the human intestinal forms renders 

 their study somewhat tedious. Very good preparations showing 

 the main features can be made by exposure to osmic vapour of 

 the wet film, which is then dried and stained by eosin azur. A 

 good method is to expose a small drop of saline emulsion of faeces 

 on a slide to the vapour of the osmic acid bottle for about ten to 

 twenty seconds and then to be spread out thinly, dry and stain. 

 It will be seen that all three types possess definite axostyles, the 

 presence of which in the human intestinal trichomonas some 

 observers seem to doubt. For instance, the figures given by 

 Brumpt in his " Precis de Parasitologie " (p. 195) do not show 



* See inset between pages 148 and 149. 



