An ancient treatment for stuttering from the time of Aristotle was gargling with solutions of pennyroyal, hyssop and thyme. Another treatment was surgical dissection on the frenum, on the grounds that movement of the tongue was being hampered. In the 1800's surgeons removed a triangular bit of tissue from the root of the tongue. In the 20th century, psychological and neurological causes have mainly been proposed. One current treatment program requires the stutterer to speak slowly and use a electronic device to set up a rhythm which can help him coordinate the timing of words.