144 Spirochaetae and Acanthia 
observations on the behaviour of spirochaetae in bugs. They however 
published the results of ten experiments (conducted in Liverpool) on 
monkeys which they sought to infect with spirochaetes through the agency 
of Acanthia lectularia. Six of the ten experiments were carried out with 
Spirochaeta duttoni alone, whilst four were carried out with bugs infected 
partly with Sp. obermeieri (American strain) and partly with Sp. duttoni. 
It is not quite clear from their paper how many bugs were infected with 
the latter spirochaete alone. Considering the experiments collectively, 
the authors named allowed 10 monkeys to be bitten by 2210 bugs which 
had previously fed on infected animals. The bugs sucked infected 
blood at different stages of the disease and in turn bit fresh uninfected 
monkeys at variable periods of time (2 to 3 or 10 to 15 days) after 
being infected. A few of the bugs were kept at a low temperature 
(5'5°C.) after sucking infected blood, but the majority were maintained 
at 20—21° C. All their results were negative. 
Klodnitzky (1908, p. 127) in Astrachan, allowed bugs to bite relapsing 
fever patients and also collected supposedly infected bugs in hospital 
wards. He examined the contents of about 30 bugs and detected 
isolated spirochaetes in them for 3—5 days after they had fed, and 
subsequently he observed what he supposed was a great multiplication 
of the spirochaetes in the bugs. His description and the two photo¬ 
micrographs which illustrate his paper leave no doubt in my mind but 
that he took the spermatozoa of the bug for spirochaetes. 
From the foregoing it will be seen that we still lack evidence proving 
that Sp. obermeieri is conveyed by bugs. The negative results obtained 
by Breinl, Kinghorn and Todd do not however exclude the possibility of 
bugs being the carriers of relapsing fever, and certainly the results 
obtained with Sp. duttoni do not weigh as evidence against bugs being 
the carriers of Sp. obermeieri. There is no evidence to support the 
hypothesis of Donitz (1907, p. 18) that European relapsing fever is 
conveyed by ticks. The observations by Karlinski and Schaudinn 
above cited indicate that further work on the subject is still required. 
Failing Spirochaeta obermeieri it appeared to me desirable to study 
the behaviour of Sp. duttoni in Acanthia lectularia and with this object 
the following experiments were carried out. 
Acanthia lectularia, received from London, were placed at 16° C. Hungry specimens were 
chosen and fed on mice in whose blood Sp. duttoni was present in large numbers. 
At the time stated in the first column, in minutes or hours, a bug (or two) was 
dissected and the intestinal contents examined fresh and stained by Giemsa’s method 
(dry films). 
