Transmission electron micrographs of eosinophils isolated from the spleen of an IL-5–transgenic mouse.⁸  Note the structural similarities shared with the zebrafish eosinophils isolated from the whole-kidney marrow displayed in micrographs shown in Figure 2 of the Balla et al article.³  Notable features include an eccentric, indented nucleus and irregularly shaped electron-dense cytoplasmic granules (left panel: ×7000 magnification; right panel: ×10 000 magnification). Micrograph prepared by Dr Elizabeth R. Fischer (Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health [NIAID, NIH]) and provided by Dr Kimberly D. Dyer (Laboratory of Allergic Diseases, NIAID, NIH).