THE STRUCTURE OF TRYPANOSOMA LEWISI. 797 
the flagellum and the nuclei, and instead of appearing as a 
very minute dot, it is usually considerably enlarged in size, 
appearing sometimes as a relatively large, diffuse patch (figs. 
70, 73). Ll regard this appearance of the blepharoplast simply 
as another instance of the tendency of the Romanowsky stain 
to form concretions, as it were, round the bodies for which 
has the affinity, whatever it may be, which is shown by 
staining. 
The flagellum presents itself as a delicate filament of even 
thickness and like ‘appearance throughout its whole length 
(fies. 10, 11, ete). I have not been able to see any structural 
differences in it in different parts. After the Romanowsky 
stain the flagellum commonly appears much thicker and quite 
coarse in structure, a state of things evidently due to the 
usual performances of this staining method. When, however, 
the Romanowsky stain is suitably extracted, the flagellum 
comes down to its normal thickness (figs. 67-69). 
Prowazek (1905) has introduced a most extraordinary 
complication of fibrils into the structure of T. lewisi (see his 
text-fig. 28, p. 359). One fibril is supposed to connect the 
karyosome with the kinetonucleus; from the latter another 
fibril runs to an “anchoring grain” situated in the post- 
nuclear region, and from this grain yet another fibril runs 
forward to the anterior end of the body. I have searched in 
vain in all my preparations, without finding a trace of this 
fibrillar system. In my smears stained with the Romanowsky 
stain, however, I find that the periplast, stained red, shows 
creases and folds often closely simulating distinct fibrils. I 
have represented some of these in figs. 70-72 (Pl. 22), and 
could have drawn many more. I have a strong suspicion that 
Prowazek’s fibrillar system is founded on nothing but acci- 
dental creases of this kind, since he remarks, “Die Fasern 
selbst lassen sich farberisch nur schwer darstellen und 
nur an weniger Objekten konnte man sie streckenweise als 
rote Fibrillen verfolgen” (loc. cit., p. 358). This so exactly 
describes what I have seen that I must express my profound 
scepticism as to the existence of Prowazek’s fibrillar system. 
