STRUCTURE OF THE VOICE ORGAN 
generally attacked, and a well-known surgeon exhibited 
some years since a preparation of a sheep so treated, in 
which the bird had performed the operation of ‘‘ colo- 
tomy,’ or cutting into the large intestine. But it is 
now certain that the kea actually prefers lean to fat, 
like our old friend Jack Sprat, but, unlike that gentle- 
man, will eat both substances. One might think 
possibly that this change of feeding habits—which may 
ultimately be responsible for a change in at least the - 
digestive organs of subsequent keas, and be thus a most 
excellent example of the influence of man upon faunas— 
having been acquired would be fixed, and that animal 
food would now be a necessity. This, however, is not 
so. Specimens at the Zoo have been fed on ordinary 
parrot food, and have thriven thereon and showed 
no symptoms of pining for unnatural mutton chops. 
Nevertheless, mutton chops have often been freely sup- 
plied to these birds when in the parrot house. The cap- 
acity for an entire change of diet gives the philosopher 
room “ furiously to think,”’ for it seems likely that many 
kinds of beasts in the past have disappeared from the 
face of nature through inability to adopt such liberal 
opinions, and it is a fact that omnivorous creatures, 
who need therefore place but little dependence upon the 
vagaries of Nature, are often of primitive and long 
existent kinds. This parrot, like others, has a voice. 
Sir Walter Buller asserts that it mews like a cat, and 
that it also utters a “‘ whistle, a chuckle, and a sup- 
pressed scream,” a round of noises which is unsurpassed 
in the bird tribe. This flexibility of voice (and it may 
be added that the kea can be instructed in the art of the 
usual parrot unpolite conversation) depends partly in 
these birds upon the complicated structure of the voice 
organ. That organ has several muscles pulling different 
ways, and thus allowing of much change in the shape of 
the air column, which causes the vocal chords to vibrate 
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