STRUCTURE AND PATHOLOGICAL SIGNIFICANCE. 251 



merely overlooked the two closely approximated thin threads, as has 

 often been done in similar cases even by skilful investigators. Apart 

 from this, the parasite in question has so striking a resemblance to 

 Tricliomonas vayinalis, that the two forms could hardly be distin- 

 guished, if the accompanying plates did not show the ciliated fringe of 

 Tricliomonas intestinalis consisting of a much larger number of cilia. 



The form of the mobile animal in its condition of rest is, according 

 to Zunker, best compared to a somewhat long almond kernel. It 

 consists of a transparent mass of protoplasm, which contains, 

 besides some irregularly scattered granules, one or two vesicular 

 structures (vacuoles ?) lying in the pointed posterior end of the body. 

 At the posterior end there is also a short spine-like process, while 

 the rounded-off anterior portion seems to exhibit a very distinct row of 

 cilia, which by their rapid action produce a continuous undulating 

 motion. Under favourable circumstances the animals were extremely 

 lively. They moved with great rapidity, and also possessed great 

 contractility, so that the form of the body often changed in an almost 

 amoeboid manner. The dimensions varied from 0*007 to O'Ol mm. in 

 breadth, and from O'Ol to O'Ol 5 mm. in length, exclusive of the long 

 tails, which were from 0'002 to 0'003 mm. long. The nearer the time 

 of death approached, the weaker the motions became. The animals 

 remained upon the same spot, turned round in a circle on the anterior 

 end, or swung like a pendulum, using the caudal extremity as a point 

 of support. Finally, they sank down motionless, lost the ciliary 

 comb, and assumed a round shape, most deceptively like the dull 

 granular clotting of a cell. The rapidity with which death followed 

 depended very essentially on the surrounding temperature, just as we 

 noted before in the cases of Trichomonas vaginalis and Cercomonas 

 intestinalis. 



What has been previously observed as to pathological and clinical 

 significance, and as to the nature of the Monad-containing fceces in the 

 case of Cercomonas intestinalis (which, according to Zunker, seems 

 much more rare than Trichomonas, since he only observed it twice 

 and Trichomonas seven times), is so perfectly applicable to this second 

 .species that 1 shall content myself with referring to it. But this much 

 may be added, that this Trichomonas occurred in acute cases of 

 typhus, peritonitis, and in severe diarrhoea, complicated by icterus and 

 pneumonia, as well as in chronic ailments (which were again generally 

 diarrhoetic). 



In conclusion, I may note that Trichomonas intestinalis, like Cerco- 

 monas intestinalis, is probably sometimes found in the human mouth. 

 I base this supposition on the researches of Steinberg, who, in the 

 above-mentioned treatise on the microscopic character of the dental 



