_Garcia_ states, in his observations, that sometimes when the rims of the vocal ligaments have come together, there remains between the arytenoid cartilages a triangular space, which does not close until the tone is produced. _Czermak_ likewise describes this process in his pathological investigations, and also a similar one with the laryngoscope. While, namely, the arytenoid cartilages seem to be wholly closed, one sees just before the beginning of the tone the vocal ligaments standing apart in a square-shaped form, and only closing together with the tone. At first, before I had attained to much practice in observation, I often saw these processes in myself, and later often in others. That these accidental forms of the glottis bear no relation to the generation of sounds, as _Funke_ truly says, is made evident by an irregularity in the combined action of the muscles of the larynx, by which the coming together of the arytenoid cartilages takes place later than that of the ligaments, or that of the ligaments later than that of the arytenoid cartilages. As recently great importance has often been ascribed to these abnormal movements of the glottis in the generation of sound, I have felt bound to mention them. RESULTS OF THE FOREGOING OBSERVATIONS In consequence of the observations above described, the following facts may be established: I. We have found five different actions of the vocal organ: 1. _The first series of tones of the chest register_, in which the whole glottis is moved by large, loose vibrations, and the arytenoid cartilages with the vocal ligaments are in action. 2. _The second series of the chest register_, when the vocal ligaments alone act, and are likewise moved by large, loose vibrations. 3. _The first series of the falsetto register_, where again the whole glottis, consisting of the arytenoid cartilages and vocal ligaments, is in action, the very fine interior edges of the ligaments, however, being alone in vibrating motion. 4. _The second series of the falsetto register_, the tones of which are generated by the vibrations of the edges alone of the vocal ligaments. 5. _The head register_, in the same manner and by the same vibrations, and with a partial closing of the vocal ligaments. II. We have learned the transitions of the registers, i.e., those tones where a different action of the vocal organ takes place; and observation has further taught us that these _natural limits of the registers cannot be exceeded without a straining that may be both seen and felt_; that is, that we may not preserve the action of a lower series for the tones of a higher. On the other hand, the vocal organs show _no straining_ when the action of a higher series of tones is kept for a lower, only the fulness of the tones is thereby diminished.