52 
THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
process, which at one end was continued on as the free portion of the flagellum. 
The undulating membrane commenced at a highly refractile spot, surrounded by an 
area also refractile and situated about one-third of the body's length from the 
posterior non-flagellated end. The protoplasm has a coarsely granular appearance, 
and differed in structure in the anterior and posterior portions of the bod}'. 
The parasite progresses generally with the flagellum in advance. When 
stationary, waves of motion move in either direction up and down the undulating 
membrane. 
In stained preparations, the parasite did not vary in form to any appreciable 
extent. The width in some tew specimens was slightly less than in the majority. 
The shape of the body is seen in Plate II, fig. 4. The protoplasm stains very deeply 
blue with Romanowsky's stain. The portion (anterior two-thirds) of the body to 
which is attached the undulating membrane is longitudinally striated, to a marked 
degree, with dark and light bands. The spongioplasm of this portion is closely 
arranged, and its hyaloplasm stains more deeply than that of the posterior third of 
the organism. With careful focussing it is seen that the light unstained bands are 
raised from the surface of the parasite. It this part of the body of the organism is 
twisted on itself, a trellis-work appearance is brought about by the crossing of the light 
stripes. The anterior two-thirds of the body ends abruptly at the macronucleus, from 
which it is separated by a narrow unstained area, probably due to a retraction of 
the protoplasm caused by the drying of the film. The light bands are continued on 
past the nucleus to the base of the posterior portion. The protoplasm of the 
posterior portion of the body has a very spongy appearance, and presents a contrast 
to the anterior. This appearance becomes more marked as the posterior extremity 
of the parasite is reached. With careful focussing a fine superficial striation can be 
made out. 
In the process of smearing the frog's blood on a slide some of these large 
parasites were injured. From a study of such specimens it can easily be made out that 
the body of the parasite is enclosed in an outer membranous covering, which on one 
side is prolonged as the undulating membrane,* alon« the tree border of which the 
flagellum is attached. In one parasite this membrane was partially stripped off and 
stained a faint reddish purple colour. In it were seen fine pink staining lines, having 
a looped arrangement and apparently running round the short axis of the 
organism. The membranous envelope is much more easily seen in the anterior 
division of the parasite. The undulating membrane commences opposite the nucleus 
as a comparatively wide fringe which is thrown into folds and takes on a faint purple 
tint. It gradually narrows towards the anterior end. Along its free border is 
attached the flagellum, staining a reddish pink. The latter commences at the 
micronucleus and ends anteriorly as a free filament. The macronucleus is situated 
~ Wasielewski und Senn. Beitrage zur Kenntniss der Flagellaten eles Rattenblutes. Zeitschr.f. Hygiene, BJ. 33, 1900. 
