The Parasitology of Pyorrhoea alveolaris. 189 



stated that it is impossible to distinguish the aS*. huccalis from the 

 *S^. refringens, but we do not think this should be difficult. In our 

 experience we find in carefully prepared specimens that the 

 S. huccalis shows blunter ends than does the S. refringens. More- 

 over, huccalis shows two to three curves only, whilst the *S'. refringens 

 shows as many as five to seven curves, which are generally very 

 graceful, and has pointed extremities. 



With regard to the treponemata found in these cases, the micro- 

 and macrodcntium are easily distinguishable. Both these forms 

 are long delicate treponemata showing long terminal flagella. The 

 depth of the coils and the width of the body, however, are very 

 different in the two species. The T. microdentium usually 

 measures 15-20 /a, and the coils are very steep and regular. The 

 T. macrodcntium, on the other hand, measure 10-15 fi, but the coils 

 are far wider and very much shallower. 



We have observed both transverse and longitudinal fission in 

 all these varieties of spirochastes, and entirely agree with Fantham 

 that looped forms can be distinguished from those forms undergoing 

 longitudinal fission. In many of these spirochsetes, we have 

 observed what has been termed by Fantham " multiple transverse 

 fission." In such cases rounded granules resembling cocci are 

 formed within the body of the spirochete, the periplast finally 

 rupturing and discharging them into the medium. 



In addition to these forms, we have noticed the presence of two 

 flagellate organisms, which we have been unable to find hitherto 

 described, and which we believe to be new species. The first of 

 these forms bears a very striking resemblance to the trypanosomes, 

 and also would appear to have affinities with the spirochsetes. 

 This is an important point, as it lends some support to Schaudinn's 

 view that certain spirochaites had a trypanosome-like phase. This 

 form occurs in scanty numbers in the pockets, and indeed we 

 have been quite unable to find it in certain pockets examined. 

 It apparently occurs in three different forms, which may for con- 

 venience be described as long, intermediate, and stumpy. The 

 typical form (PI. XV, fig. 1) has a long sinuous body, provided with 

 an undulating membrane. The anterior end is broad, and ends 

 with a long flagellum, the posterior end thins off to a short point. 

 The average breadth of body in this form is about 1-5 to 1 * 8 /i, 

 whilst the length in the longer forms may measure fully 15 fi. 

 Division appears to be by longitudinal fission, but as quite small 

 short forms may also be seen, we think that there is probably a 

 second mode of reproduction, which we have not yet been able to 

 determine. 



The second form which we have observed appears to be present 

 in the majority of cases of pyorrhcca, but in very varying numbers. 

 Its form is somewhat sickle-shaped (PI. XV, fig. 2), and it is pro- 

 vided with a single lateral flagellum, and which appears to be con- 



