CORPORA AMYLACEA (CA) are round, intracytoplasmic bodies which distend the processes of fibrous astrocytes.1Everyone develops them with advancing age. They are frequently found in the hippocampus, the subependymal zones of the lateral and third ventricles, the floor of the fourth ventricle, the medulla oblongata, and the spinal cord. In these locations, they are usually encountered along the margins of blood vessels or beneath the pia. They are the focus of increasing interest because they raise certain provocative questions: (1) What are they made of? (2) What can they tell us about the normal metabolism of astrocytes? (3) What are their implications with regard to the mechanisms of aging in the central nervous system? (4) Why are they found in increased numbers in association with many diffuse degenerative and focal disorders of the nervous system? The histochemical and chemical natures of corpora amylacea have remained points at