This biphasic stimulator was owned (and probably built) by neurosurgeon James Sloan Robertson (1905-1978). The machine was most likely used during surgical treatment of patients suffering from epilepsy. An electrode would be attached to the machine, which would help the surgeon to locate the boundaries of a lesion, and also ensure that an undamaged part of the brain was not about to be removed. The device is clearly handmade, and is a precursor to machines used in later deep brain recording techniques.
Robertson was one of the first modern neurosurgeons in the UK. After graduating in medicine from the University of Glasgow in 1928, he worked as a surgeon at the Glasgow Royal Infirmary. He then trained for a year under renowned neurosurgeon, Wilder Penfield, at the Neurological Institute, Montreal. During the Second World War, Robertson worked as a specialist in neurosurgery at the Emergency Medical Services Hospital, Killearn. He was one of the founders of the Institute of Neurological Sciences at Glasgow. Robertson became a Fellow of the College in 1962.