48 
Blood Parasites 
The Spirochaete in the Noctule. 
In this bat there were even fewer spirochaetes than in the 
Pipistrelle and the blood contained no other parasites except an 
embryo filaria which I found in one slide. 
Films were made from the peripheral blood, heart, lung, spleen, 
kidney and liver, but spirochaetes were only found in those from the 
peripheral vessels and heart, and even here they were present in 
extremely small numbers. 
The measurement of 48 specimens, all that could be found in a 
large number of preparations, showed them to be 15‘9 p in length with 
8T spirals. The longest which might be dividing was 25 p in length 
with 12 turns, the shortest 10 p with 6 turns. 
The spirochaetes were straight or slightly curved with regular 
shallow spirals which were somewhat deeper and more pronounced 
in the centre and which gradually diminished towards the extremities. 
The ends were sharply pointed but no flagella could be detected. 
They closely resembled those found in the Pipistrelle, and also stained 
red with Giemsa. (Plate II, fig. 22 and Plate IV, fig. 48.) 
It is interesting to note that both in the Pipistrelle and Noctule 
it was practically useless to search for the spirochaetes in any position 
of the blood film except at the very commencement of the smear. 
During an examination of more than 100 films I never once detected a 
spirochaete at the end of the smear, probably only once or twice in the 
middle of the smear, and in all other cases they were found in the first 
i or i of the film. This peculiarity applies also to the position of 
T. vespertilionis. 
Method of examination suitable for detection of these and possibly 
other spirochaetes. I discovered the first spirochaete whilst I was 
examining a blood film of tbe Pipistrelle for dividing forms of Achro- 
maticus which were very numerous in that particular bat. The 
preparation was stained, and mounted in parolein and I was using the 
yV objective. I may add that it is exceedingly easy to pass over 
one of these fine spirochaetes without detecting it, even with a 
magnification of 600 or more, and the search for them in many films is 
well nigh hopeless. After I had found a spirochaete, I adopted a 
method for their detection which I have long used for finding 
S. pallida, and which I have not seen described yet. The method 
depends on the principle; 1st, that structures which are stained with 
a fluorescent dye, e.g. eosin, fuchsin, fluorescin, etc., when examined 
