than a loud-sounding note.  Observations upon anencephalous monsters (infants born without the great brain) show that breathing and crying can occur without the cerebral hemispheres; moreover, Goltz’s dog, in which all the brain had been removed except the stem and base, was able to bark, growl, and snarl, indicating that the primitive function of the vocal instrument can be performed by the lower centres of the brain situated in the medulla oblongata.  But the animal growled and barked when the attendant, who fed it daily, approached to give it food, which was a clear indication that the bark and growl had lost both its affective and cognitive significance; it was, indeed, a purely automatic reflex action.  It was dependent upon a stimulus arousing an excitation in an instinctive automatic nervous mechanism in the medulla oblongata and spinal cord presiding over synergic groups of muscles habitually brought into action for this simplest form of vocalisation, connected with the primitive emotion of anger.

I will now consider at greater length each part of the vocal instrument.

I. THE BELLOWS

[Illustration:  Fig 1]

[Description:  Fig. 1.—­Front view of the thorax showing the breastbone, to which on either side are attached the (shaded) rib cartilages.  The remainder of the thoracic cage is formed by the ribs attached behind to the spine, which is only seen below.  The lungs are represented filling the chest cavity, except a little to the left of the breastbone, below where the pericardium is shown (black).  It can be seen that the ribs slope forwards and downwards, and that they increase in length from above downwards, so that if elevated by the muscles attached to them, they will tend to push forward the elastic cartilages and breastbone and so increase the antero-posterior diameter of the chest; moreover, the ribs being elastic will tend to give a little at the angle, and so the lateral diameter of the chest will be increased.]

The bellows consists of the lungs enclosed in the movable thorax.  The latter may be likened to a cage; it is formed by the spine behind and the ribs, which are attached by cartilages to the breastbone (sternum) in front (vide fig. 1).  The ribs and cartilages, as the diagram shows, form a series of hoops which increase in length from above downwards; moreover, they slope obliquely downwards and inwards (vide fig. 2).  The ribs are jointed behind to the vertebrae in such a way that muscles attached to them can, by shortening, elevate them; the effect is that the longer ribs are raised, and pushing forward the breastbone and cartilages, the thoracic cage enlarges from before back; but being elastic, the hoops will give a little and cause some expansion from side to side; moreover, when the ribs are raised, each one is rotated on its axis in such a way that the lower border tends towards eversion; the total effect of this rotation is a lateral expansion