EXPLANATION OF PLATE.

Figure 1.—Forms seen in fresh preparations of the peripheral blood.

Figure 2.—Forms seen in films stained by Romanowski's stain.

Figure 3.—Oval form due to position adopted by a mature vermicule. The nucleus
                  shews transverse bands of chromatin.

Figure 4.—Longitudinal fission form.

Figure 5.—Forms possibly arising from an act of longitudinal fission.

Figure 6.—Imperfectly stained form, shewing similarity to malignant tertian crescent.

Figure 7.—Vermicules in fresh blood preparation.

Figure 8.—Vermicules stained by Romanowski's stain.

Figure 9.—Vermicules in contents of mid-grit of louse. A single field.

Figure 10.—Dissection shewing alimentary canal of louse and contained vermicules.

Figure 11.—Pyloric ampulla containing numerous vermicule forms. Fresh prepara-
                   tion.

Figures 12 and 13.—Young forms of cyst.

Figure 14.—Form shewing clear outer area and granular contents.

Figure 15.—Fully matured cyst.

Figure 16.—Zygotes containing sporozoits.

Figure 17.—Zygotes in process of development.

Figure 18.—Sporozoits in normal saline.

Figure 19.—Sporozoits; stained preparation.

Figure 20.—Adult louse shewing a single fully matured cyst in abdomen.