38 
BIRD-LIFE. 
explanation of the singular properties of the bird's 
yoice. 
These properties consist of strength, fulness, roundness 
and elasticity; qualities which are only accorded to man 
in a higher degree. Fulness and strength have their 
foundation, probably, in the extraordinary means of 
inflation, which belongs to the bird, coupled with the 
possession of two larynxes; the first renders possible the 
excessively great, though quite inexplicable, expenditure 
of moving air; and the latter gives strength to the tones, 
principally, perhaps, by means of the “ drum," that 
singular cartilaginous cavity in the wind-pipe, which 
apparently can have no other meaning. The flexibility 
of the voice is owing to the extraordinary mobility of the 
larynx, whose lesser ligaments can produce an increasing 
altitude of each tone through an augmentation of their 
vibrations. The richness and beauty of tone give 
meaning to the bird’s voice. There are, indeed, many 
birds which seldom utter other than shrill and shrieking 
tones; these, however, are comparatively few, and are, 
at all events, not very protracted. Absolutely dumb 
birds are unknown. The greater number possess voices 
so rich and so varied in tone that to them a language 
bordering on conversation could, in a broad sense, be 
possible. Birds not only speak to, but even amuse, each 
other. They have a number of words or sounds denoting 
different sensations, impressions and ideas; and these 
sounds are so marked and so expressive as to be 
understood, not only amongst the same species, but 
convey a meaning even to man himself. Every observer 
understands the language of a bird he is acquainted with; 
for he soon gets to learn the varied tones of tenderness, 
love, joy, desire, health and satisfaction, and how to 
