AND CONTENTS OF THE MOUTH. 181 



by similar masses of diplococci ; even the entanglements of the 

 type «, u, are not wanting (Fig. 2). 



The chains belong to types c and d (Fig. 2), but are generally 

 longer, thick, branched off in bundles of 10 or 15, which take up 

 to three visual fields, and exactly represent the disposition of the 

 bundles of filaments. In the same chain small diplococci may 

 alternate with eUiptical bacteria and medium-sized dumb-bells — all 

 perfectly equal, which form the largest number. 



In these we have been unable to find fructifications, so that 

 this second phase may be held as analogous to mycelium, or the 

 vegetation, of fungi, partly immersed, partly creeping. 



Third Phase {Inc07?ipkfe aerial vegetation). — This is generally 

 met with in the tartar of the teeth. Its predominant elements are 

 the large filaments, often very long, bent, and re-united in bundles, 

 taking a brilliant colour with iodine ; and the stumps. I shall 

 not describe these well-known forms, having already done so in 

 speaking of the primary and secondary species of Miller. 



I would rather point out some features, noticeable in a certain 

 number of these filaments, when I have the opportunity of finding 

 them isolated (especially in the unstained preparations), such 

 features not having been considered by previous authors. 



The first is a division into two or three branches (Fig. 9), 

 which I think must be taken for a kind of radical system of this 

 microphite, for divisions are never detected towards its apex ; and, 

 at its opposite end, a swelling or head is noticed, which is a 

 proper form of points twined upwards (as in b). In a the filament 

 is broken towards the top and exhibits two long roots ; in b, there 

 are three hood-shaped roots. Both appear to be swollen at their 

 ends, like haustoria. 



What can be the use of these barbs or roots, unless to obtain 

 a firm foundation in the ground ? And to what purpose is this 

 firm foundation, unless to support higher forms of vegetation ? 



The other feature is that of the swelling, which we will call 

 apices or heads, being found at the top of the respective filaments, 

 as in b and <:, and these are of varied form, at times containing a 

 kind of nucleus. There are others which might be styled knotty, 

 being found along the filament ; of these we give no drawing, as 

 they are similar to the preceding ones. 



