138 
Spirochaetosis 
this can hardly be avoided. Yet no foreigner, or Russian of a better 
class, ever catches relapsing fever. To this may be added the fact that 
when I asked for clothes-lice and promised to pay a kopek for two, 
the attendants from the Night Hostel brought me next morning a 
small ounce bottle crammed with Pediculus capitis and P. vesti- 
mentorum collected off the sleepers. If relapsing fever were trans¬ 
mitted by bed-bugs it would be much more disseminated than it is 
at present in Moscow. 
In Balfour’s synoptical table a morphological distinction appears 
to be made between the spirochaetes of European, Central African and 
American relapsing fever and the spirochaetes of the Egyptian, 
Algerian and Asiatic relapsing fevers, from the observation of Fraenkel 
that the former have peritrichous flagella, whilst nothing is known 
about their presence in the latter. 
As far as my personal observations go, I have often seen a terminal 
filament in S. recurrentis when using dark-ground illumination, whilst 
so far the “flagella” have only been seen in dry films, which have 
been specially prepared. I believe that the peritrichous “ flagella ” 
shown in Fraenkel’s (1907) and also Zettnow’s (1906) excellent photo¬ 
graphs are threads of periplast, as Schellack (1908) and Karwacki (1912) 
suggest. 
Another explanation of the undeniable appearances in the 
specimens of the authors who consider flagella to be an integral part 
of spirochaetes, is that they may be rudimentary structures similar 
to the “ribs” seen in the “undulating membrane” of Spirochaeta 
{Cristispira) balbianii; it is known that Fantham (1909) found in 
the crystalline style of Tapes aureus a continuous series of long and 
short, narrow and broad forms ; also spirochaetes with sharply pointed, 
tapering or rounded ends and others whose two ends were unequally 
pointed or rounded. A glance at Fantham’s figures shows all grada¬ 
tions in shape from the typical Cristispira balbianii to the spirochaete 
as seen in the blood of mammals. Therefore it is possible that these 
“ flagellar structures ” in S. recurrentis, duttoni and novyi may be 
similar to those seen in a much more developed form in the spiro¬ 
chaetes of oysters and mussels. 
Regarding the terminal filament it appears to be a common feature 
of many spirochaetes. It has been seen repeatedly in Treponema 
pallidum, also in Noguchi’s (1911) cultures of this parasite, by 
Schellack (1908) in S. recurrentis, by Prowazek and Hoffman in S. 
balanitidis, in S. dentium by Hartmann and Muhlens, by Zettnow 
