Figure 1. Eosinophil morphology. At the upper left is a characteristic eosinophil with coarse granules and a bilobed nucleus. At the lower right is neutrophil with its typical multilobed nucleus and faintly staining granules. The smaller pale reddish-staining cells in the background are erythrocytes; these cells are biconcave, hence doughnut shaped and have an apparent hole in the centre.

Figure 2. Visualization of an eosinophil by electron microscopy. (a) Shows a portion of a human eosinophil with the nucleus at the upper left and the cytoplasmic membrane at the lower right. The distinctive specific granules fill the cytoplasm and have a substructure consisting of an electron-dense core (C) and an electron-lucent matrix (M) (28 000×). The core takes many shapes. (b) Shows a single-rat eosinophil granule with a bilayer granule membrane (GM), the amorphous matrix (M) and the core (C). At this magnification (375 000×) the core shows a linear pattern. (c) Shows the core of the rat eosinophil granule at high magnification (800 000×) and reveals a linear array in two dimensions. (Miller F, De Harven E and Palade GE (1966) The Structure of eosinophil leukocyte granules in rodents and in man. Journal of Cell Biology 31: 349.)

Figure 3. Charcot–Leyden crystals. The Charcot–Leyden crystals have a characteristic morphology consisting of hexagonal dipyramids. These crystals are formed from eosinophils and also basophils; the crystals above were derived from purified eosinophils. The frame on the left (160×) shows the purity of this preparation and the frame on the right (400×) shows the distinctive appearance of the crystals. (Gleich GJ, Loegering DA, Mann KG and Maldonado JE (1976) Comparative properties of the Charcot–Leyden crystal protein and the major basic protein from human eosinophils. The Journal of Clinical Investigation 57: 633.)