A. C. Coles 
3 
During October 1916, thanks to the kindness of Capt. Adrian Stokes, 
R.A.M.C., I received many films of blood and liver taken from guinea-pigs 
inoculated with the blood of cases of Infectious Jaundice occurring in France, 
and in this way I became familiar with the spirochaete. Later he sent me 
eight films of blood taken from a soldier on the 4th day of the disease. I spent 
more than a fortnight examining these but entirely failed to find a single 
spirochaete. 
Out of six films sent subsequently from a case (Corpl. MacG.) on the 2nd 
day of the disease, after numerous very prolonged examinations I found two 
definite spirochaetes in one film. These I have included in the photomicro¬ 
graphs which I had the pleasure of taking for his paper. Dr G. T. Western 
has recently sent me a series of blood and liver films, unfixed and unstained, 
from guinea-pigs inoculated from cases of Weil’s Disease. I take the oppor¬ 
tunity of expressing here my thanks to both these workers. 
When I learnt that Capt. Stokes, like the Japanese observers, had found 
pathogenic S. icterohaemorrhagiae in the kidneys of rats caught in the trenches, 
I wondered whether any of the common rats in England would also harbour 
them, so I examined at different times during the year, the kidneys of 14 
rats that had been caught in the neighbourhood, but with no success, although 
I carefully centrifuged the emulsion before making a microscopic examination. 
Then Noguchi’s paper appeared and I started again and examined another 
five rats but still without success. 
However, on November 1st, a half grown common rat, just killed and 
very much mauled, was brought to me from the immediate neighbourhood, 
and in the emulsion made from the kidneys I found numerous typical actively 
moving spirochaetes. 
METHODS. 
The kidneys are taken from the body of the rat, and the surrounding fat 
and capsule carefully removed. They are then placed in a small sterile vessel 
and a few drops of freshly boiled and cooled distilled water or normal saline 
added and the kidneys are cut up in very small pieces and a thick emulsion 
made. 
From a drop of this emulsion very thin films are prepared and are allowed 
to dry in the air. When quite dry a few drops of distilled water, previously 
made slightly alkaline, are poured over the surface and allowed to act for 
about 30 seconds. They are then stained in Giemsa, without any fixation, 
for three to four hours. Two stained films and two fresh coverglass prepara¬ 
tions were examined by dark ground illumination in every case. 
It is of the greatest importance that both the films and fresh preparations 
should be as thin as possible, otherwise it is easy to overlook the spirochaetes. 
Throughout this investigation I have relied entirely on the method of 
dark ground illumination which I have been using for the last six or seven 
years for the detection of S. 'pallida in particular and other spirochaetes in 
general, and which I (1915) have described in detail elsewhere. Those experts 
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