38 
Blood Parasites 
associated with a moderate infection of T. vespertilionis. In two others 
the parasites were moderately frequent and in one of these there was a 
very slight infection with trypanosomes. The remaining three bats 
contained very few parasites, and in one it required a prolonged search 
before a single parasite could be found. The infected Pipistrelles came 
from Reading. 
The parasites are found almost entirely in the red corpuscles, exceed¬ 
ingly few free forms being met with. 
They are usually round, oval or irregular in shape. The protoplasm 
stains a very faint blue colour whilst the chromatin is deeply stained 
with Giemsa. 
The presence of the parasite does not seem to affect the staining 
reaction of the red corpuscles. In preparations stained with Leishman 
and Giemsa’s stain the corpuscles show no sign of degeneration such as 
is seen in simple tertian and malignant tertian malaria, and in some 
forms of haemamoeba of the monkey. 
The parasites usually lie somewhat out of the centre of the corpuscle, 
and there is no pigment at any stage in their development. 
The commonest forms are round or oval with the nucleus occupying 
about or of the margin. Sometimes the parasite extends almost 
across the diameter of a red cell and then it assumes somewhat the 
shape of an egg, but true pear-shaped parasites are certainly uncommon. 
As the parasite becomes larger it occupies about § of the red cell 
and the marginal chromatin shows signs of division into two, and a little 
later into four part.s. Irregularly shaped amoeboid forms are common 
and in these the chromatin no longer occupies a marginal position. A 
red cell may contain three or four parasites but these are usually some¬ 
what ill defined unless they are the immediate result of division. 
It is somewhat difficult to determine what precisely is the method 
of division of these parasites, but it would appear as if the nucleus first 
divides into two, then four, nodules of chromatin, and these extend round 
the margin of the protoplasm until the whole parasite appears like a 
square having a nodule of chromatin at each corner. The protoplasm 
then seems to divide so that an appearance of a Maltese cross results, 
and the elements sej^arate outwards, at first attached by a thin line of 
protoplasm at their apices. This breaks and one finds four small pear- 
shaped parasites arranged in tlie form of a cross. It is this method of 
division which suggests to my mind the probability of the relationship 
of the Ackromaticus to one of the divisions of the piroplasms, possibly 
to the Nuttallia. (Plate IV, fig. 40.) 
