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A BIOMETRIC STUDY OF TRYPANOSOMA 
GAMBIENSE. 
By EDWARD KINDLE, Ph.D., A.R.O.S., 
Beit Memorial Research Felloiv. 
{From the Quick Laboratory, Cambridge.) 
The three forms of Trypanosoma gambiense have been described so 
often that a few words of apology are needed before bringing forward 
the following note on the subject. 
In their memoir on the morphology of this parasite, Salviu-Moore 
and Breinl (1907) deny the existence of any true dimorphism or 
trimorphism in T. gambiense, but regard the forms, often described 
as distinct, as merely “ arbitrarily chosen examples in a continuous 
series of dimensions.” Although the three types, as shewn by Minchin 
(1908), appear quite distinct when compared side by side, yet the 
existence of transition stages between the two extremes of “long” and 
“ stumpy ” forms makes it possible that the two latter are merely 
extreme variations of one type. If this were the case, however, a curve 
plotted fi'Oin the dimensions of a reasonably large number of individuals 
should present only one apex, which graphically expresses the fact that 
the variation is around one mean point. 
In order, therefore, to determine whether the variations in the size 
of T. gambiense are around one mean point or more, the dimensions of 
a thousand individuals have been plotted in the form of two curves 
The method of obtaining these dimensions was as follows : 
A film was prepared from the ‘blood of a heavily infected rat 
containing numerous parasites in each microscopic field. The film 
was dried, fixed in absolute alcohol, and stained with Giemsa in the 
usual way. The general outline of the body obtained with this dry 
film method is far superior to that obtained after employing wet 
