436 
to demonstrate peritrichal flagella, either in fresh or in stained 
specimens, have completely failed. The central core, or chromatic 
part, does not always stain uniformly, but in certain parasites lighter 
and darker areas are noticeable, either throughout the whole length 
or confined to one part of the parasite (figs, i, 2). Very frequently, 
especially in spirochaetes which are disappearing from the circulation, 
the whole chromatic core seems to be broken up into an irregular 
number of granules (fig. 3). In this stage of infection the spirochaetes 
often, show one or more swellings, either in the centre or at one end 
(figs. 4, 5). A fairly constant appearance, which has been previously 
described by various observers in Spirochoeta obermeieri and 
Spirochczta duttoni, is a small unstained transverse band situated at 
about one-third of the length of the parasite (fig. 6). 
A considerable amount of work was done with the object of 
demonstrating an undulating membrane. Although in specimens 
stained with Giemsa’s solution an appearance was sometimes seen 
which resembled an undulating membrane, this was, in my opinion, 
due only to the flatten, ng out of the spirals of the paras,te. In wet 
trims, even after a prolonged staining by Heidenha.n's method, no 
trace of an undulating membrane could be seen. 
The division of Spirochata duttoni is, as a rule, transverse, 
the paras, tes mcrease in length and become thinner in the middle; 
is mner part then elongates more and more until the two 
individuals separate (figs. 7 , 8). It i s very probable that the unstained 
future H Ue y 56611 T para51te <%■ <9 » ‘he point of the 
loTg udtfd ° n “ SUbS6qUent f ~ rse d-sion. Occasionally, 
IheTsaooe dlVIS1 ° n f WaS take place, especially at the time of 
a nd tWs r3nCe ' 3f the Parasites from the peripheral circulation, 
(o'increase ° “ the °^ns the paras,te was seen 
spirochaete and 't T^t dlV,S,on com mencing at one end of the 
Judging from tl ^ eXtendm S along its entire length (fig. g) 
appear that this' process^ f T P ^ S ' tes at this sta fTe, it would 
instances, at this stage of the ““ P " at,vel r . °ne. In rare 
engulfed by phagocytes. ’ parasites were seen bein S 
occasions,'seen inZT'j m I0 ' «*■ 
close to each other t h° W ° s P lrochaetes were observed lying 
other, touch, ng at certa.n points. The one was stained 
