343 
ON THE PECULIAR MORPHOLOGY 
OF A TRYPANOSOME FROM A CASE 
OF SLEEPING SICKNESS AND THE 
POSSIBILITY OF ITS BEING A NEW 
SPECIES (T. RHODESIENSE)* 
BY 
J. w. W. STEPHENS, M.D. (Cantab), D.P.H., 
AND 
H. B. FANTHAM, D.Sc. (Lond.), B.A. (Cantab.) 
(.Received for publication 16 December , 191O; 
PREFATORY NOTE 
As already stated in a report to the Advisory Committee for 
the Tropical Diseases Research Fund, dated May 9 > ' 9 10 ’ no 1C 
early in February, 1910, while examining in class work a staine 
specimen of rat’s blood infected with what was suppose to e 
T. gambiense, a marked peculiarity in the morphology • 
peculiarity was so striking that I doubted whether the trypanosome 
with which I was dealing was really T. gambiense. On ma mg 
enquiries I was told that the strain was deri\ed from a cas ® 
sleeping sickness then in Prof. Ross’s clinic in the Ro) al 
Hospital, Liverpool. To make certain that there was no, error in 
this statement I myself infected a rat from the patients 
The same forms were, however, again encountered. After con\ inci g 
myself that these forms were constantly present in in ecte r ’ 
and that they were not shown by the rats infected wlt ^ c ° rn 
laboratory strain of T. gambiense maintained at tie 1 
Laboratory, I decided through pressure of work to as r - , 
(now working in the Liverpool School of Tropical - e > icin ®’ g 
funds allotted by the Advisory Committee for the ropica 
* Read before The Royal Society on Nov. 3, 19 10 ' and re P rmtcd fr0! " P ‘° L ' ^ 
Vol. LXXXIII, p. 28, with addenda. 
