CAUSE OF DEFECTIVE UTTERANCE: Now, let us consider the cause of defective utterance. What is it that causes the organ, muscle or parts to fail properly to function? The first and most obvious conclusion would be that there was some inherent defect in the organ, muscle or part which failed to function. But experience has proved that this is usually not the case. An examination of two thousand cases of defective utterance, including many others besides stuttering and stammering, revealed three-tenths of one per cent. with an organic defect--that is, a defect in the organs themselves. In other words, only three persons out of every thousand afflicted with defective utterance were found to have any physical shortcoming that was responsible for the affliction. Take any of these two thousand cases--say those that stammered, for instance. What was the cause of their difficulty, if it did not lie in the organs used in the production of speech? This is the question that long puzzled investigators in the field of speech defects. Like Darwin, they said: "It must be this, for if it is not this, then what is it?" If stuttering and stammering are not caused by actual physical defects in the organs themselves, what then can be the cause? DUE TO A LACK OF CO-ORDINATION: Cases of stammering and stuttering where no organic defect is present are due to a lack of co-ordination between the brain and the muscles of speech. In other words, the harmony between the brain and the speech organs which normally result in smooth working and perfect speech has been interrupted. The brain impulses are no longer properly transmitted to and executed by the muscles of speech. This failure to transmit properly brain messages or this lack of co-ordination may take one of two forms: it may result in an UNDER-innervation of the organs of speech, which results in loose, uncontrolled repetitions of a word, sound or syllable, or it may take the form of an overinnervation of the vocal organ with the result that it is so intensely contracted as to be entirely closed, causing the "sticking" or inability to pronounce even a sound, so common to the stammerer. Suppose that you try to say the word "tray." Do not articulate the sounds. Merely make the initial effort to say it. What happens? Simply this: The tip of the tongue comes in contact with the upper front teeth at their base and as you progress in your attempt to say "t," the tongue flattens itself against the roof of the mouth, moving from the tip of the tongue toward its base. If you are a stammerer, you will probably find in endeavoring to say this word, that your vocal organs fail to respond quickly and correctly to the set of brain messages which should result in the proper enunciation of the word "tray." Your tongue clings to the roof of your mouth, your mouth remains open, you suffer a rush of blood to the face, due to your powerful and unsuccessful effort to articulate, and the word refuses to be spoken.