'o Kitchen <>// the Inferior Larynx in Birds. \ January 



'trilling' apparatus, the air passing to and from the lungs on each of 

 its sides. Some of the outer bronchial half-rings are susceptible 

 of a rotary motion on their axes, and are important agents in 

 modifying the voice. Opposite the os transversale, on the outer 

 sides of the bronchi, is a sort of fold of mucous membrane that 

 presents a lip or projection something like the vocal ligament in 

 the human larynx. There is one to each bronchus. This pro- 

 jection is probably formed by the process of the shutting up of 

 the syrinx when the neck is retracted, and is really more the 

 analogue of the ventricular fold in the mammalian larynx than 

 of the vocal coril. There is no doubt but that this lip, when 

 approximated to the •cross-bone,' is capable of throwing the air 

 current coming from the lungs into vocal, or rather sound vi- 

 brations. Every one has heard the 'squeak' that a fowl often emits 

 when hopping about with its head cut off, and it is probable that 

 the sound is produced by the syrinx. Several small muscles. 

 varying in number from two to five, and which appertain to the 

 lower larynx exclusively, coil around it, and enable it to make 

 tense the tvmpaniform membrane, to close up the glotti, and to 

 rotate its framework. An examination of the syrinx indicates 

 that it undoubtedly may have an influence in the modification of 

 the voice in its intensity, and in production of the 'trill.' The 

 valve being shut, and the muscles of expiration being brought into 

 play, a greater air pressure in the bodv can be brought to bear on 

 the structures which throw the air-blast into vibration, and the 

 gradual opening and shutting of this valve would give crescendo 

 and decrescendo effects to the notes. It is even probable that 

 some of the notes originate here, and are only modified on their 

 way to the outer world through the upper air-passages, but this 

 cannot lie to so great a degree as is widely stated. The Blackbird 

 has a curious 'querF in its song, that seems as if it originates as 

 deep down in the bird as this organ is located. We have spent 

 many a spare moment observing the Blackbird in the Aviary at 

 Central Park, trying to detect the exact location of the production 

 of this sound. It is related that Cuvier cut the trachea across the 

 neck at the middle, and even took away the upper part of the 

 trachea in the Magpie, and yet, it is stated that the bird contin- 

 ued to cry as before the operation, the voice not being less strong 

 or sharp. We should want to thirst for a knowledge of compar- 

 ative physiology more than at present before repeating so cruel 



