36 H. B. FANTHAM. 
difference in the reaction of the two organisms to gentian- 
violet is not worthy of account as a possible factor in dis- 
cussing the question of the affinities of the two organisms. 
It has been suggested by Minchin (17) that an undulating 
membrane is of value to a Protist possessing it as a means of 
pushing aside obstacles such as blood-corpuscles occurring in 
the medium in which it lives. This may be so, but it seems to 
me that the primary function of the membrane of Spirochetes 
is that of a locomotor agent. Also, few obstacles are 
encountered by Spirochetes while they remain within the 
style itself. However, Minchin’s suggestion is an interesting 
one, for much débris and partially digested food are 
encountered by S. balbianii and 8. anodonte while they 
are free in the lumen of the gut. 
The Nucleus. 
The nucleus of these two Spirochetes under discussion is 
diffuse, and is disposed over the whole length of the attenuate 
cylindrical body, except just at the extremities, about 2 pu 
from each end. 
In the more commonly occurring forms of 8. balbianii, 
those presumably in the resting state, the nucleus consists of 
transversely arranged bars or rodlets of chromatin disposed 
at nearly regular intervals, and placed transversely to the 
long axis of the body. These chromatin masses appear as 
rodlets, but it is possible that they might be discs or bands. 
To decide what is the real character of the chromatin masses 
is not at all easy in such a small organism, S. balbianii 
being a cylinder of 2m diameter, and S. anodonte only 
about one third of that diameter—namely, about 0°7 n. 
I think, however, that these masses are rodlets, because on 
focussing they are not seen passing through to the far side, 
as would occur in the case of peripheral bands. . If they were 
discs, that is, continuous right across the interior of the 
organism, they would divide the organism into segments, and 
the parasites might be expected to separate easily at, or 
