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36 blood corpuscle, every leucocyte, and every pigmented body, even though it be not included in a corpuscle. He must not expect to find parasites in every corpuscle, or even in every field; and he certainly must not expect, as the beginner usually does, to find in every slide the beautifully regular segmenting form or "rosette body" or the weird-looking flagellated body made familiar to us by so many illustrations. Such bodies, though really present somewhere and in some form at one time or another in every case, are among the least common of the many phases of the malaria parasite; they are met with only under very definite and not very constantly encountered conditions, and are not very often seen at an ordinary clinical examination.

In most cases the parasite is discovered in the first field or two examined; but in not a few instances dozens of fields may have to be scrutinized before a single parasite is found. Therefore no examination can be said to be complete, in a negative sense, until at least half an hour has been spent over several suitably prepared slides.

The intracorpuscular forms most frequently met with have the appearance either of small specks of pale protoplasm, or of larger masses of pale protoplasm containing grains of black pigment. Close watching discovers that the former are endowed with amœboid movement, and that they continually change shape and position in the affected corpuscles. As these movements are an important test of the parasitic nature of the body sought, they should be carefully looked for. The smallest protoplasmic specks look like washed-out smudges of dirty-white paint, half hidden by the hæmoglobin; they are sometimes hard to see. Their parasitic nature can readily be determined by their movements; by their soft, ill-defined margins; and by the fact that they tend now and again, on first removal from the body, and permanently later, to assume the appearance of tiny white rings which show up very distinctly in the hæmoglobin of the corpuscle. These features readily distinguish them from the sharply defined, clear,