ANIMAL PAEASITES. 7 



161, fig. 33). Trichomonas vaginalis only occurs in women with 

 gonorrliceal discharge, or with an abundant vaginal secretion 

 mixed with mucus- and pus-corpuscles; never in a normal and 

 healthy vaginal secretion, but only in pathological conditions. 

 The mucus, however, need not be frothy, as Donne supposes, so 

 long as it is not quite normal. Kolliker and Scanzoni found it in 

 the vaginal (never in the cervical) mucus of both pregnant and 

 unimpregnated women, especially in the yellowish, creamy, and acid 

 mucus ; sometimes in neutral, but never in alkaline mucus. From 

 their granulated appearance, their form, size, and structure, the 

 mucus-corpuscles closely resemble this Infusorium ; they both also 

 generally lie in masses together. All these things, with the 

 very sluggish movements of the parasite, have caused it hitherto 

 to be very commonly overlooked, and confounded with the mucus- 

 corpuscles. The prolongation at the anterior end, which is even 

 sometimes drawn out into an elliptical form, and furnished with 

 a delicate, long filament (flagellum], distinguishes the parasite 

 from the epithelium. The body of the parasite is O01 millim. 

 (Duj.), or 0-020-04 millim. = 0-008 O'OIS'" (Koll. and Scanz.), 

 in length; the flagellum, 0-028 0'033 millim. (Duj.), or 0'04 

 0-08 millim. = 0-015 0-030'" (Koll. and Scanz.), in length, 

 sometimes double or triple, and furnished with several (7 8 

 according to Dujardin, 4 5 according to Donne) short cilia in 

 continual movement, which greatly facilitate the recognition of 

 the animal. A mouth, which Donne states he saw under the 

 flagellum, was found neither by Dujardin nor by Kolliker and 

 Scanzoni, who sometimes saw, beneath the cilia, a delicate furrow 

 running obliquely. The vacuoles observed by Dujardin in the 

 body of the animalcule were only seen by Kolliker and Scanzoni, 

 during its contact with water or weak sugar and water, in which 

 the animals swell up into a globular form and soon become motion- 

 less, and then closely resemble ciliated cells. When examined in 

 pure vaginal mucus, the parasites exhibit a very lively infusorial 

 swarming; and those who speak of similarity to ciliated epithe- 

 lium must have made use of water in their investigations. 

 Kolliker and Scanzoni observed no leech-like movements, true con- 

 tractions and expansions of the body, or adhesion by the so-called 

 posterior extremity, which is produced into a delicate, but still 

 rather thick, stiff, immoveable, and rather long process. Unfor- 

 tunately they did not attempt to transfer vaginal mucus with 

 Trichomonads to the healthy vagina of women which were not 



