A little more than 96 per cent. of the causes of stammering which the author has examined can be traced back to one of the five causes shown below: 1--Mimicry or Imitation 2--Fright or severe nerve shock 3--Fall or injury of some sort 4--Heredity 5--Disease Let us take up these familiar causes of stuttering or stammering in the order in which we have set them down and learn something more of them. The first and one of the most common causes is Mimicry, or, as it is probably more often called, Imitation. Mimicry or Imitation is almost wholly confined to children. After reaching the age of discretion, the adult is usually of sufficient intelligence to refrain from mimicking or imitating a person who stutters or stammers. The average small boy, however, (or girl, for that matter) seems to find delight in mocking and imitating a playmate who stutters or stammers, and so keen is this delight that he persists in this practice day after day until (as its own punishment) the practice of mockery or mimicry brings upon the boy himself the affliction in which he found his fun. It may be noted, however, that Imitation is not always conscious, but often unconscious. The small child begins to imitate the stuttering companion without knowing that he engages in imitation. This practice, notwithstanding the fact that it is unconscious, soon develops into stuttering, without any cause being assignable by the parent until investigation develops that unconscious and even unnoticed imitation is the basic cause of the defective utterance. It has been definitely determined that stuttering may be communicable through contagious impressions, especially among children of tender age whose minds are subject to the slightest impressions. For this reason, it is not advisable for parents to allow children to play with others who stutter or stammer, nor is it charitable to allow a child who stutters or stammers to play with other children who are not so afflicted. So far-reaching are the effects of Imitation or Mimicry that in certain cases, children have been known to contract stuttering from associating with a deaf-mute whose expressions were made chiefly in the form of grunts and inarticulate sounds. FRIGHT OR SEVERE NERVE SHOCK: Another common cause of stammering is fright or nervous shock, which may have been brought about in countless ways. One boy who came to me some time ago stated that he had swallowed a nail when about six years of age and that this was the cause of his stammering. The logical conclusion in a case like this would be that the nail had injured the vocal organs, but an examination proved that there was no organic defect and that the stammering was caused, not by injury directly to the vocal organs but by the nervous shock occasioned by swallowing the nail.