STUDIES ON CEYLON HA#MATOZOA. 685 
commonly present, and this occurrence is quite casual. ‘They 
may possibly be of a fatty nature, and be dissolved out by 
the alcohol with which the slide is treated. Whatever their 
nature, they have no visible equivalent in the stained prepa- 
rations. The membrane presents the usual structureless 
appearance, and takes up the stains very faintly and evenly. 
In the Romanowsky films, and also, though less frequently, 
in wet hematoxylin material, a line is to be seen on the 
membrane, just immediately inside the flagellum; it sug- 
gests a supporting or skeletal structure and takes up the 
plasma stain. 
The flagellum runs at the edge of the membrane, and can 
be traced back very close to the kinetonucleus, but not as a 
rule actually into it. A minute granule! can occasionally be 
seen just at the root, but it is not by any means always visible. 
The kinetonucleus is rod-shaped; in Romanowsky prepara- 
tions it shows as a more massive structure than in the wet 
films treated with Heidenhain. It is always surrounded by 
a slightly clearer area of protoplasm, but there is no sign of 
a definite vacuole in its neighbourhood as is described for 
some of the mammalian 'l'rypanosomes. 
In a dried film the Trypanosome is practically presented in 
one plane, and a certain amount of widening out occurs, this 
causes a disturbance of the internal structures to a greater 
or less extent. ‘The form in question during its sojourn in 
the blood of the vertebrate is, relatively speaking, a massive 
creature, it is oval in cross-section, as can be seen in paraffin 
sections from the lung. It is therefore not particularly well 
adapted for the drying method. In the wet films the tropho- 
nucleus shows a large chromatic karyosome surrounded by a 
clear area, which, in turn, is bounded by a sharply-defined 
ring, which takes on a nearly black colour with iron haema- 
toxylin (Pl. 16, figs. 1 and 2). I propose to use the word 
nuclear membrane for this outer ring. I merely do this as a 
matter of convenience; it is not at all clear how far it can be 
1 This corresponds apparently with the blepharoblast of Minchin, 
°Q. J. M. Sci.,’ vol. 52, 1908. 
