Medical Officers of the Army of India.

33

in fig. K. 3,4,5. In this case the parasite was undoubtedly extracorpuscular, the
red cell, which it had left remained perfectly normal in all its appearances. The
rapidity of approach of the macrophage, the way in which the long process of
granular protoplasm flowed towards the parasite and the remarkable manner in
which it avoided intervening red cells in its course, presented a most remarkable
picture. It certainly seemed that the parasite in leaving the red blood cell had
exposed itself to attack, and the phenomenon suggested that the organism had
commenced to lose vitality at an early period after having separated from its
source of nourishment, and had thus increased the attraction exercised by it
on the phagocyte.

   2nd. —In addition to the intracorpuscular forms, several free, more or less
globular parasites similar to A. 2d could be seen at this stage, and a few larger
globular bodies A. 3. These had no amœboid movement, had perfectly clear,
rather highly refractive, protoplasmic cell contents, and presented many small
pigment granules, frequently, but not always, arranged peripherally and in lively
motion. The larger forms were of the same diameter as a red blood cell, or
nearly so, and are to be met with in all stages of the fever though they are
frequently by no means numerous and are thus likely to escape observation.

   (2) At 20 hours:—

   The parasites had increased considerably in size, they still retained their
powers of lively amœboid movement as shown in figs. B, 1a to 1d, and 2a to 2d,
the various stages in each of which were drawn at intervals ranging from
2 to 5 minutes. The pigment granules were larger and more numerous and had
active movements.

   This active movement of the melanin pigment is observable at some
stage at least of the life of all forms of the malarial parasite. It appears
to be of two well marked kinds: (a ) In certain forms a dancing bubbling motion
is seen, in which the granules rise up in the parasite, then spread out towards
its sides irregularly. This has been well compared by Laveran to the
movement of pigment particles in boiling water: (b ) A slower, but equally
marked, movement of the pigment granules, in which they seem to flow along
in the protoplasm from one part to another, frequently in lines or streams.
This is well seen in the intra corpuscular stages of the quartan and tertian forms
up to the time when the pigment becomes quiescent, as described below, pre-
vious to sporulation.

   Towards this time (20 to 24 hours), the bodies appeared to have become
completely intracorpuscular, they did not present the appearances described
above, when examined by oblique open illumination, and were never seen to
leave the red cells.

   (3) At 36 hours:—

   The parasite was found to be still larger, filling nearly 2/3rds of the red cell,

F