On the Singing of Birds. 283 



for her want of that force and power which a more ample 

 organ confers on the male. 



Mr. Conway asks, " Do not the females of some birds sing 

 occasionally as well as the males ? " This question I can 

 answer in the affirmative. The subdued and interesting warble 

 of the hedge sparrow (Accentor modularis Cuv.) is not at 

 all uncommonly to be heard. The female of the reed bunting 

 may, also, frequently be heard in the close of the evening ; and 

 some others of the smaller species of songsters ; but their notes 

 are always very feeble, and less musical than those of the 

 males, owing, I have no doubt, to the smallness and weakness 

 of the tracheal tube, as before observed. 



I believe that musicians generally allow the notes of birds 

 of all kinds to bear a strong resemblance to wind instruments, 

 and the tones of the human voice more accurately to resemble 

 those of the iEolian harp; and this difference seems to be 

 thus accounted for: the different intonations of the human 

 voice are produced by the tension of two chords, called chorda 

 vocales, which are stretched across the aperture of the superior 

 part of the laryngeal tube, called rima glottidis [the aperture 

 named the glottis *]. But these chorda vocales are wanting 

 in song birds, and their various intonations and modulations 

 are made by the extending and contracting of the laryngeal 

 tube itself, which is both coated and lined with a very fine 

 membrane, so as to give it every possible degree of flexibility. 

 Besides these essentials to the production of so many varied 

 tones, the laryngeal tube is further furnished with five pairs 

 of muscles, called the muscles of voice, which greatly assist in 

 contracting the diameter of the laryngeal tube, in almost 

 imperceptible degrees, so as to produce almost every degree 

 of intonation and modulation so apparent in our feathered 

 warblers. We have only to witness the singing of the canary 

 or nightingale in a cage, to perceive the contraction and 

 dilatation of the larynx, in order to assure ourselves that these 

 observations are in perfect accordance with the construction 



[* It has been shown by M. Dodart (Rees's Cyclopaedia, vol. xxxvii., 

 art. Voice), that the extension and contraction or the glottis is caused by 

 two tendinous cords in its two lips. The more the aperture is lessened, 

 the higher becomes the tone of voice, because the wind then passes through 

 with greater rapidity. The small size of the glottis in female singers causes 

 the high tone of their voice. 



There is didactic information on the organs, and more their functions, 

 concerned in man's articulation, in the 8vo, not the 12mo, Murray's Eng- 

 lish Grammar, ed. 26th, p. 32 — 35., under the title " The Nature of Arti- 

 culation explained." Information on the glottis is included ; but its figure 

 is not stated : this, in a MS. from which the initial part of this note is taken, 

 is compared to an oval, coming to a point at each end.] 



y 2 



