Among the leading German theorists, Karl Ludwig Merkel, a professor of medicine at Leipzig University, described stuttering in 1842 as a “failure of confidence in the ability to communicate”; this notion was adopted and expanded by Reinhold Denhardt, who wrote in 1890: “If we examine the mental processes during stuttering, we see that the disturbance typifies the struggle between two opposing forces. The volition which tries to convert the thought into speech is pitted against the belief that we are unable to accomplish what we intend. One drives, the other restrains.” Merkel and Denhardt acquired adherents, and some American physicians took up the theme. One, E W. Scripture, described stuttering in 1912 as a learned response become habitual and maintained by anxiety.