A. C. Coles 
47 
The Spiy'ochaete in the Pipistrelle. 
The spirochaetes are present in very small numbers, on an average 
not more than two or three being found in a film measuring 1 by 
I inch. 
Films were made from the peripheral blood, heart, lung, spleen, liver 
and kidney, but spirochaetes were only found in the peripheral and 
heart blood and in that from the lung. 
They were associated with a very large number of the unpigmented 
intracorpuscular parasites (Achromaticus). 
Measurements. The average measurement of 100 spirochaetes was 
15'37 //, long with 7'5 turns or spirals. The shortest specimen found was 
10 fjb in length with 5 turns, the longest 23'3 p long with 12 turns. The 
filament of the spirochaete measured about 0'2 to 0'3 p in thickness : 
the distance of the summit of one spiral to that of the next spiral was 
about 2 p, whilst the depth of the turns measured from the level of 
the summit of one to the level of the summit of another spiral varied 
from about 0'5 to TO/a. These latter measurements were taken from 
photo-micrographs. (Plate II, fig. 21 and Plate IV, fig. 47.) 
The longitudinal axis of the spirochaetes was generally straight or 
slightly curved, a few were bent at right angles. The spirals are for the 
most part very regular, being somewhat deeper in the centre and 
gradually diminishing towards the extremities. The ends of the 
spirochaetes are drawn out to a fine point, but I could in no case, even 
after prolonged examination, detect the presence of flagella or terminal 
filaments. 
Almost invariably long specimens show signs of transverse division, 
the central wave or turn becoming flattened out, thinner, and more 
faintly stained, whilst in other cases a distinct break in the continuity 
of the filament was seen. 
During the examination of 103 spirochaetes I saw no indication of 
longitudinal division taking place, and in only one was the filament 
recurved. 
This spirochaete constantly stains a reddish colour with Giemsa, 
never a blue tint. 
The parasites met with in the blood from the heart and lung 
showed practically no difference from those found in the peripheral 
circulation, except that the spirals in the former were a little deeper 
and more pronounced than in the latter. 
