260 
ON THE OCCURRENCE OF HERPETOMONADS (?) 
IN GERBILS. 
By ANDREW BALFOUR, M.D., 
Director-in-Chief, Wellcome Bureau of Scientific Research. 
I was much interested in the paper on Herpetomonads in mice in 
the June number of Parasitology (Fantham and Porter, pp. 128-132). 
In 1904 or 1905 when working at trypanosomiasis at Khartoum I came 
across a flagellate in the peripheral blood of a gerbil ( Gerbillus pygargus) 
which was clearly not a trypanosome and the nature of which I was 
unable to identify. 
The facts are as follows: 
My laboratory assistant, Mr Friedrichs, was examining a cover slip 
preparation from one of the control animals and observed a very 
actively moving parasite amongst the red blood corpuscles. He called 
my attention to it and I examined the film with much interest, for it 
seemed clear that we were dealing with a new blood parasite. It was 
not easy to examine, for its movements were exceedingly rapid and 
jerky, but I could see that it was flagellated and I specially noticed 
that its posterior end was curved or flexed a little upon itself so that 
it resembled a hook. 
After watching it for a little I was called away and my assistant 
by some mistake unfortunately removed the cover glass and cleaned 
it and the slide so that I was unable to study the film further or to 
obtain a stained preparation. There was, so far as I could tell, only 
the single parasite in the film and I am certain that it was not a 
trypanosome, although a trypanosome of the T. lewisi type has been 
found in the Sudan gerbil. The gerbil was still available and I examined 
a large number of blood films from it but I failed to find any other 
parasites in its blood. So far as I can remember I also examined blood 
obtained from it post-mortem without result. 
