IT IS assumed that most electroencephalographic laboratories employ a more or less standard type of electrode, viz., a flattened solder pellet, which is attached to the scalp with collodion. For several years my associates and I have utilized a convenient clip-on electrode which was adapted from a somewhat similar type of electrode, as described by Darrow 1 in 1940. This clip-on type of electrode eliminates the application of collodion, thereby accelerating the procedure of applying electrodes. It is simply and securely attached to the scalp without discomfort to the patient. This method can be applied only when the patient has a sufficient amount of hair. Simultaneous recordings made with solder pellet and clip-on electrodes were found to be identical. CONSTRUCTION AND APPLICATION OF THE CLIP-ON ELECTRODE A rust-resistant metal is preferred if it is available, but we have found that any semipliable metal can be used. As an item of