A. C. Coles 
49 
on a dark ground stand out prominently, whilst blue stained structures 
are very inconspicuous; 2nd, that if the medium in which the red 
stained organism lie be of very low refractive index they are exceedingly 
conspicuous and can be detected with a comparatively low power ; but 
if mounted in balsam, cedar oil, parolein or water they are only seen 
with difficulty. 
Films are stained with Gierasa, Leishman, etc. in the ordinary way 
if they are going to be kept and subsequently examined with an 
immersion lens ; if not, with eosin, fuchsin or even red ink for a few 
minutes. Wash, dry, but do not mount. Examine dry, without any 
mounting medium at all, with dark ground illumination, using dry lens 
and moderate ocular. I use ^ apo. with comp, ocular 6 or 12 or No. 18 for 
detection of S. jJctUida and dark ground illumination obtained by means 
of a stop used with an achromatic condenser, as with the oil immersion 
condensers the oil is troublesome if one has to examine a large area. I 
do not put a coverglass on the preparation, but lengthen the tube of 
the microscope about 3 to 4 inches to get perfect definition. 
By this means I can detect 50 spirochaetes in less time than I could 
find one with ^ oil immersion used with ordinary illumination. I mark 
the position of the spirochaete by means of a diamond object marker, 
and log its position on the mechanical stage, and subsequently mount 
the preparation in parolein, and examine at leisure with the oil 
immersion lens. 
The spirochaetes found in the pipistrelle and in the noctule were 
very similar in size, number of spirals and staining reaction and 
probably belong to the same species. 
Nicolle and Comte have found that bats in Northern Africa suffer 
from fever due to the presence of spirochaetes which they have named 
S. vespertilionis. I have not been able to find a description of these, and 
it is quite possible that those I have found in bats in England may be 
identical. If however they should prove to be a new species I would 
suggest the name of Spirochaeta vesperuginis, sp. n. 
I examined some of the ectoparasites, especially ticks, found on some 
of the bats bub with entirely negative results. 
Grahamella or Graham-Smith’s Bodies. 
I have found these in the blood of the mole, field mouse, field vole, 
water vole and in very young rats. They are almost always to be found 
in the mole sometimes associated with T. talpae and sometimes with 
Elleipsisoma thomsoni. 
Parasitology vii 
4 
