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i] recognized as a pale, somewhat ill-defined disc of protoplasm occupying a larger or smaller area within a proportion of the red blood-corpuscles (Fig. 1, a). Scattered through this pale body are a number of intensely black or reddish-black particles—an excrementitious material called heemozoin.

Changes in the parasite.—By making fresh blood preparations and repeating his examinations at short serial intervals, the observer is enabled to infer that the following changes systematically occur in this disc of pigmented protoplasm. After a time, as the parasite matures, the scattered haemozoin particles collect into little groups, sometimes into radiating lines. These heemozoin groups subsequently concentrate into one or two larger and more or less central blocks, around which the pale protoplasm of the parasite arranges itself in minute segments which finally acquire a globular form and appear as well-defined spherules (Fig. 1, b, c, d). The including blood corpuscle then breaks down, and the spherules, none of which contains haemozoin, fall apart, and, along with the clump or clumps of haemozoin, become free in the liquor sanguinis (Fig. l, e). The phagocytes now quickly absorb the haemozoin and many of the spherules. A proportion of the latter, escaping the phagocytes, attach themselves to other blood corpuscles, which they contrive to enter (Fig. 1. f). In the interior of these newly infected corpuscles the young parasites exhibit active amoeboid movement, shooting out and retracting long pseudopodia, and growing at the expense of the haemoglobin (Fig. 1, g). This substance they assimilate, converting it into the pale protoplasmic material constituting the mass of the parasite and into the haemozoin particles (Fig. 1, h, i). As the parasite becomes larger its amoeboid movements gradually slow down until all motion finally ceases; just before the formation of spherules and completion of the cycle (Fig. 1, j), beyond slight translation