It has been our purpose to study the finer microscopic changes that take place in the various cellular elements of the brain in cases of fatal injury of the head. Many descriptions have been given of gross changes in such cases, usually under the general appellations of concussion, contusion, hemorrhage and "wet brain." In such reports, occasional references have been made to the microscopic changes. In previous communications a general survey of the field was first outlined,1 and later a more detailed investigation was made concerning the changes in the choroid plexus and ependyma.2
The introduction of the newer metallic methods by Cajal and his co-workers opened a new field for investigation of the supporting elements of the central nervous system. These methods have already been utilized in the study of brain injury in experimental animals. So far as we know, such investigations have not been conducted on