An autopsy was made 1 hour after the death of a child on the 3rd day of an attack of measles, before the appearance of Koplik's spots or the rash. The presence of virus in the spleen, lung, kidney, and lymph nodes was demonstrated in cultures of these tissues by the development of the characteristic cytopathology.

In the patient's organs the well-known epithelial and reticuloendothelial giant cells of measles were present as the only specific lesion, and some observations on their genesis were made. Epithelial giant cells developed in the tracheal and bronchial mucosa (but not in the alveoli); the earliest change was a fine eosinophilic granularity in the cytoplasm of a sheet of adjacent cells, and the disappearance of the cell walls. The granules then became coarser, and the nuclei swelled and developed ovoid ampho-philic inclusions. Later the nuclei became more basophilic, and clumped at the base of the cyto-plasmic mass, which finally separated from the unchanged basal cells to lie freely in the bronchial lumen. Reticuloendothelial giant cells occurred in all the lymphoid tissue examined and contained up to more than 50 nuclei. Some of the smaller giant cells were regarded as having been formed by the phagocytosis of lymphoid cells by macrophages, but this might not apply to the larger masses.