﻿TREPONEMA PERTENUIS CASTELLAN I OF YAWS. 447 



turn up an end or the ends of the spiral so as to look down through part 

 of it and view another part from the side. That such bends should 

 frequently be caused by the spreading and drying of the serum is readily 

 to be believed for the reason that we often see the same thing entirely 

 in profile, that is, the spiral turns are still preserved, but the whole spiral 

 so bent as to form two or three sides of a quadrangle. 



Type E may present the terminal features of any of the above but it 

 also shows in its continuity a complete, circular loop, or more than one. 

 The spiral wire assumes a similar appearance if one turn be pressed 

 down or back. 



Type F represents a short, loosely curved organism attached to a ring 

 or two rings, one at either end. This, we think, differs from D only in 

 the proportions of the spiral viewed from the end, and in the fact that the 

 part viewed in profile has the regularity of its curves more altered by pres- 

 sure or drying. 



Type G represents various irregular forms which differ from the more 

 characteristic individuals in form only, not in size or staining power. It 

 is possible to produce all of them by pressure or traction applied in various 

 ways to the wire spiral. 



Type H embraces the individuals which show dots in some part of 

 their continuity. These have been referred to by various writers as 

 chromatin dots, as representing nucleus, blepharoplast, etc. Whether or 

 not they be such, or are merely kinks or twists in the organism, we do 

 not know. We are unable to determine any constancy in the frequency, 

 number, or localization of their occurrence, and an analogous appearance 

 may be caused in the wire coil by kinking or twisting it. 



These various types may be found pure or in a great variety of com- 

 binations, such as B C, G D, C D H, H G, A H, etc. 



Types A, B and C are seen in the wet preparations, and of the three, 

 C is by far the most common. It is unusual to see in such preparations 

 any individuals which do not show the knob-like ends and the regular 

 curves throughout their length. The other forms D, E, F, G, and H we 

 have rarely or never seen in wet preparations, but occasionally we have 

 observed individuals, particularly in old ones, which presented a some- 

 what beaded appearance that might represent type H of the stained 

 specimens. 



MOTILITY. 



In neither fresh nor stained specimens have we seen anything that we 

 interpreted as an undulating membrane, nor anything that was differ- 

 entiated as a flagellum in the distinct manner in which flagella are 

 differentiated on certain bacteria or trypanosomata. The motility of the 

 organisms as seen in wet preparations probably varies from the extremely 

 active movement already mentioned, which permits one to see a flash of 



