THE H^MOFLAGELLATES. 317 



From this, and later papers (149 and 151) by tlie same authors, 

 ii appears that S. ref ring ens is not met with in pure 

 syphiHtic lesions; S. pallida, on the other hand, occurs 

 regularly both in the primary affections and in the secondary 

 eruptive formations, as well as in the internal products and 

 developments associated with the disease. 



It can, therefore, be said that there is more probability of 

 S. pallida having some causal relation to syphilis than there 

 is of S. ref ringens. 



Besides the above, other differences between the two 

 parasites, with regard to behaviour and structure, are to be 

 observed. The spiral^ of S. pallida is much narrower, more 

 acute, and composed of many more turns" than that of S. 

 ref ringens (cf. hg. 64 b, c) ; it is, in short, more like a cork- 

 screw than a series of curves, thus differing considerably 

 from the usual type of spiral in a Spirochasta. Moreover, 

 the former parasite is very difficult to stain by the methods 

 used in other cases, while S. ref ringens stains readily. 



In his later comparative note on Spirochieta^, Scbaudiun 

 (1. c.) shows that S. pallida differs also in more fundamental 

 respects from other Spirochtetfe. Infixed and stained pre- 

 parations he was unable to demonstrate the presence of the 

 undulating membrane which is so apparent in other forms 

 when similarly stained (cf. figs. 63, 64) ; although from the 

 movements of the parasites during life, he is inclined to sus- 

 pect the existence of one, doubtless extremely thin. Again, 

 the body tapers finely at both ends, and Schaudinn believes 

 there is really a long delicate flagellum at each extremity 

 (fig. 64c) . At times he observed individuals with two flagella 

 at one end, probably indicative of longitudinal division. For 

 these reasons Schaudinn agrees with Vuillemin (152), who 

 separates S. pallida both from Spirochaeta on the one 



^ Its dimensions are as follows: lengtb, from 4-14 ft; breadth extremely 

 thiu, in; the number of turns is given as from 6-14, but in the later notes 

 as from 10-26. 



^ When in its " spirochsetiform " phase, ought perhaps to be added (see 

 below). 



