relative to Pneumatic Medicine. 259 
nous blood ceases to imbibe oxygen, and hence the heart, 
unstimulated by oxygen, ceases to contract, the arteries to 
vibrate ; and hence the whole machine, although sound and 
entire in every part, yet on a sudden, like a “aide whose 
pendulum is stopped, remains entirely at rest. 
In the watch, if we move but the pendulum, the wheels 
are immediately put into motion, the clock again correctly 
marks its hours and minutes as before: so likewise in the 
animal machine, if the blood can but be influenced by oxy- 
gen, the heart recovers its action, the brain its energy, and 
the nerves their sensibility; such is the wonderful harmo- 
nious consent of parts! " 
From this privation of oxygen in drowning and suspen- 
sion, we can now explain why the blood grows dark, the 
lips and countenance livid, arid why the body quickly loses 
its animal heat. That the motion of the heart depends upon 
the air thrown into the lungs, was established by the illus- 
trious Hook, a century ago, before the Royal Society. He 
laid open the thorax of a dog, cut away the ribs and dia- 
phragm, and removing the pericardium, he kept the animal 
alive above an hour by means of a pair of bellows. It was 
observed, that as often as he left off blowing, and the lungs 
were collapsed, the dog fell into convulsive motions, and 
revived again upon renewing the blast, and the heart began 
afresh to beat. John Hunter repeated the same experiment, 
and hence concludes, as with still-born children, in sus- 
pended animation, the first thing is to force air into the 
lungs to restore the heart’s action. For this purpose, John 
Hunter invented a pair of bellows of such a construction, 
that by one action fresh air is thrown into the lungs, and by 
another it is pumped out again, to imitate artificial breath- 
ing. This invention may be seen at Sayigny’s. But in this 
case no such instrument could be procured ; I therefore re- 
quested a common pair of bellows, and by inserting the 
nozzle up one nostril, while the mouth and opposite nostril 
were closed by a forcible pressure, the Bec were expanded 
with common air. 
We are now come to the next process. The heart or 
R2 nerves 
