AND CONTENTS OF THE MOUTH. 165 



activity, and cocci and bacteria not motile are wandering spores 

 in a quiescent state. 



Leber and Rottenstein found the fine violet staining with iodine 

 and the acids to be a characteristic of buccal microbes (included 

 by them in a single species of Leptothrix). Miller, however, 

 considers such forms to be different species, although they show 

 the same behaviour towards staining re-agents, for the reason that 

 the filaments oi Leptothrix 2ire not articulated (as stated by Robin). 

 On the contrary, the bacilli or filaments under iodine re-agents are 

 articulated. Now, can this distinctive character be sufficient to 

 classify a species ? I shall show later that, besides articulations, 

 bacilli may be found, or knotty little rods in continuity with small 

 chains, and the latter with fertile filaments (not articulated), as in 

 Figs. 9 and lo. This demonstrates the fact that such filaments or 

 bacilli, either articulated or not, or simply in beaded forms or 

 chains, do not constitute a difference of species. Moreover, the 

 filaments more woody and articulated, found in the lower layer of 

 the patina, or, owing to the friction, are left exposed, so that the 

 remaining stems become thick and hard, and their internal 

 gemmules give rise to enclosed bacteria. Vignal was not of a 

 different opinion in holding Leptothrix to be a fungus of the mouth, 

 which he had reared, although it showed transverse segmenta- 

 tions easily discernible in aniline. Likewise, Miller, in his article 

 on Leptothrix gigantea, as we shall see later, entertained the same 

 opinion. 



Quite recently, the dumb-bell bacteria and other fungi of the 

 mouth were identified with Bacterium termo by Stockwell, Clark, 

 and others. In the preceding Memoir we held this identity as 

 plausible ; but Miller positively rejects it because the title of Bac- 

 teriufn termo would embrace a mass of very different forms and 

 species. He likewise rejects the title of Leptothrix buccalis (given 

 by Robin) and of dental filaments (by Biihlmann), names which 

 Miller would have banished from microphitology. However, he 

 would give the name of Leptothrix innomi?iata to those little-known 

 filaments which appear to constitute a group or a species differing 

 from other fungi. It is clear that the author alludes to our fertile 

 filaments, making of them a separate species. 



The Leptothrix innominata of Miller (the real Leptothrix akin 



