“Thus the organs act with a double difference: 1. The cavity of the larynx contracts itself more when the voice is intense than when it is feeble. 2. The superior ligaments are contracted, so as to reduce the small diameter of the ellipse to a width of two or three lines. But however powerful these contractions may be, neither the cartilages of Wrisberg, nor the superior ligaments themselves, ever close sufficiently to prevent the passage of the air, or even to render it difficult. This fact, which is verified also with regard to the falsetto and head registers, suffices to prove that the superior ligaments do not fill a generative part in the formation of the voice. We may draw the same conclusion by considering the position occupied by the somewhat feeble muscles which correspond to these ligaments; they cover externally the extremity of the diverging fibres of the thyro-arytenoid muscles, and take part especially in the contractions of the cavity of the larynx during the formation of the high notes of the chest and head registers. PRODUCTION OF THE FALSETTO “The low notes of the falsetto show the glottis infinitely better than the unisons of the chest voice, and produce vibrations more extended and more distinct. Its vibrating sides, formed by the anterior apophyses of the arytenoid cartilages and by the ligaments, become gradually shorter as the voice ascends; at the notes la si (a¹ b¹) the apophyses take part only at their summits; and in these notes there results a weakness similar to that which we have remarked in the chest notes an octave below. At the notes do re (c♯² d²), the ligaments alone continue to act; then begins the series of notes called the _head voice_. The moment in which the action of the apophyses ceases exhibits in the female voice a very sensible difference to the ear and in the organ itself. Lastly, we verify that up to the highest sounds of the register the glottis continues to diminish in length and in width. “If we compare the two registers in these movements, we shall find some analogies in them; the sides of the glottis formed at first by the apophyses and the ligaments become shorter by degrees, and end by consisting only of the ligaments. The chest register is divided into two parts, corresponding to these two states of the glottis. The register of falsetto-head presents a complete similarity, and in a still more striking manner. “On other points, on the contrary, these same registers are very unlike. The length of the glottis necessary to form a falsetto note always exceeds that which produces the unison of the chest. The movements which agitate the sides of the glottis are also augmented, and keep the vibrating orifice continually half opened, which naturally produces a great waste of air. A last trait of difference is in the increased extent of that elliptic surface.