[Neurology and photographic illustration in the medical book].

The mutual influence between G. B. A. Duchenne (de Boulogne) (1806-1875), who published in 1862 the first known medical books illustrated with photographs, and J.M. Charcot (1825-1893), whose appointment as "Médecin de la Salpêtrière" occurred in the same year, has been of great importance for the history of medical illustration. The development of medical photography at the Salpêtrière has been continuous, absorbing also a stream sprung from another Paris hospital, the Hôpital Saint Louis (A. Hardy and A. de Montmeja, 1868). The first Department of Medical Photography was installed by the "Assistance Publique" at the Salpêtrière (1878). The books and journals were for the greater part published by two publishing houses: J. B. Baillière and Delahaye and his successors. Attention is drawn to the fact that the third edition of Duchenne's major work (1872) is no longer illustrated by photographs but contains engravings from those photographs. Other books and articles are illustrated with photographs but one is increasingly confronted with a great number of drawings of engravings made from photographs. The reasons for this change are discussed. It appears that a photograph may serve as an illustration but that for an educational or a research purpose it has another function: to preserve the image to be studied, the authors preferring to sort out the essential information (or what was thought to be so) in the form of drawings or engravings.