29 
2. Large I ntr a-corpuscular Forms (Fig. 6).— 
They appear as more or less extensive areas of blue 
protoplasm, with one or more distinct red areas. Pig¬ 
ment may be seen scattered over the parasite. These 
large forms are generally simple tertian or quartan 
parasites. 
3. Crescents and Spherical Bodies .■—These are 
most definite bodies, and readily recognized by 
the coarse pigment granules centrally situated. The 
presence of this pigment should absolutely preclude 
the possibility of mistaking distorted red cells, cres¬ 
centic in shape, or a crescentic mass of platelets, for 
parasites. In neither of these is there a definite 
central pigment mass, nor should a foreign body be 
mistaken for a crescent. Moreover, crescents again 
have quite definite outlines, and shew a red-stained 
central portion and blue extremities. 
Fig. 7. Pigmented Large Mononuclear Leucocytes 
The same criteria apply to the spherical form of 
the crescent. 
4. Pigmented Leucocytes (Fig. 7).—Large leuco¬ 
cytes with a large nucleus. Pigment (melanin) may 
occur scattered about the periphery of the cell or in 
little clumps, or even in very fine powdery grains. 
The pigment is brownish-black in colour. Skin pig¬ 
ment may be seen in epithelium scales or free in the 
specimen, but the definite position of the pigment in 
the protoplasm of the leucocyte characterizes melanin. 
