A reconsideration of the original report of Alzheimer and of the description of case 1 by Perusini in 1908, published in 1910, suggests that they were describing the same case. Both the temporal evidence and the clinical description make this conclusion inescapable. The histopathology of this first case shows some features that are not characteristic of the histological pattern of the modern Alzheimer, namely demyelination of the central white matter and metachromatic deposits in the spinal cord.