ANIMAL PARASITES. 9 



in the mucus of the teeth. Lebeaume described the tartar of 

 the teeth as the habitation and product of these Infusoria, and 

 considered the tartar as a polypary ; and Mandl even (' Comptes 

 rendus de TAcad, des Sciences/ tome xvii, p. 213) supposed the 

 tartar to be produced by the aggregation of calcareous remains of 

 bacillar Vibriones (Leeuwenhoek's Bacillarias) from the mucus of 

 the mouth. The latter were said to occur in large quantities, 

 especially in the coating of the tongue, when the diet was hard 

 and non-stimulant, as well as in cases of deranged digestion, but 

 to be destroyed by heat, muriatic acid, and spirituous beverages. 

 R.Ficinus makes the following statement (' Journ. der Chirurgie 

 und Augenheilkunde von Walther und Ammon/ Bd. 36, or new 

 series, Bd. 6, 1847, p. 4) regarding the animal structures in the 

 dental mucus. In the yellowish-white dental mucus, amongst 

 the peculiar filaments of Leeuwenhoek and Biihlmann (Mullens 

 1 Archiv/ 1840), closely aggregated, very small granules, epithelial 

 cells, and mucus-globules, make their appearance in various 

 quantities, arid sometimes single Infusoria which have accidentally 

 got into the mouth with food and drink. In the interstices re- 

 maining between the granular substance, especially on the addition 

 of water or saliva, we see an extraordinary quantity of small, 

 roundish, and longish corpuscles, which are only visible with high 

 magnifying powers, which move about briskly with a revolving 

 motion, remain restlessly on particular granules or filaments, or 

 move about upon them, lay themselves on one side, or vibrate, 

 attaching themselves by one end, and acquire a conical form. 

 These are automatic movements of an animal nature, independent 

 of currents or molecular movements, and perfectly resemble 

 movements in search of nourishment. The form of the body of 

 these animalcules appears to be an ellipsoid, divided in the 

 middle by a slight constriction, like a bean. Their trans- 

 verse diameter amounts to O'OOOOS 8, and their longitudinal 

 diameter to 0*00016 20" Par. The animalcule is met with par- 

 ticularly in the vertical position, when it appears as a globule 

 f iJoo T^OO'" Par., and on account of this figure it was regarded by 

 Eisenmann as a Monas Lens. More rarely it is seen in a horizontal 

 position. When moving quietly the form of its body may be 

 more distinctly recognised, when it has approached objects which 

 offer it nourishment. Then we sometimes see, in the constriction 

 at the middle of the body, a lip-like elevation, below which 

 Ficinus supposed the oral opening to be situated, if the animal- 

 cule be not destitute of a mouth. 



