Make a hole through a wine cork of sufficient size to admit a smaller
cork; through which make another hole, and fix it into the larger
one. Tie the corks thus fixed into the neck of a bullock’s bladder,
previously exhausted of air; let a tube from a bottle generating
hydrogen pass very tightly through the aperture in the small cork, and
the gas will distend and fill the bladder. The instant it is full,
withdraw the inner cork, and either prevent the escape of the gas by
means of the thumb, or cork it closely, till the operator is ready to
_breathe the gas_; to do which, he should put the open cork into his
mouth, and take _one_ inspiration, when, on immediately speaking, his
voice will be remarkably shrill. The effect will pass off in a few
seconds.