(vide fig. 18).  The best method of breathing is that which is most natural; there should not be a protruded abdomen on the one hand, nor an unduly inflated chest on the other hand; the maximum expansion should involve the lower part of the chest and the uppermost part of the abdomen on a level of an inch or more below the tip of the breastbone; the expansion of the ribs should be maintained as long as possible.  In short phrases the movement may be limited to an ascent of the diaphragm, over which we have not the same control as we have of the elevation of the ribs; but it is better to reserve the costal air, over which we have more voluntary control, for maintaining a continuous pressure and for varying the pressure.

II.  THE REED

I will now pass on to the consideration of the voice-box, or larynx, containing the reed portion of the vocal instrument.

[Illustration:  FIG. 4 From Behnke’s “Mechanism of the Human Voice”]

[Description:  FIG. 4.—­The cartilages of the larynx or voice-box.  A large portion of the shield cartilage on the right side has been cut away, in order to show the two pyramid cartilages; these are seen jointed by their bases with the ring cartilage; anteriorly are seen the two vocal processes which give attachment to the two vocal cords (white ligaments), which extend across the voice-box to be inserted in front in the angle of the shield cartilage.  Groups of muscles pull upon these cartilages in such a manner as to increase, or diminish, the chink between the vocal cord in ordinary inspiration and expiration; in phonation a group of muscles approximate the cords, while another muscle makes them tense.]

The Larynx.—­The larynx is situated at the top of the sound-pipe (trachea or windpipe), and consists of a framework of cartilages articulated or jointed with one another so as to permit of movement (vide fig. 4).  The cartilages are called by names which indicate their form and shape:  (1) shield or thyroid, (2) the ring or cricoid, and (3) a pair of pyramidal or arytenoid cartilages.  Besides these there is the epiglottis, which from its situation above the glottis acts more or less as a lid.  The shield cartilage is attached by ligaments and muscles to the bone (hyoid) in the root of the tongue, a pair of muscles also connect this cartilage with the sternum or breastbone.  The ring cartilage is attached to the windpipe by its lower border; by its upper border in front it is connected with the inner surface of the shield cartilage by a ligament; it is also jointed on either side with the shield cartilage.  The posterior part of the ring cartilage is much wider than the anterior portion, and seated upon its upper and posterior rim and articulated with it by separate joints are the two pyramidal cartilages (vide fig. 4).  The two vocal cords as shown in the diagram are attached to the shield cartilage