8o Dr. Philip's experiments to ascertain the principle 
the muscles after the nerves are divided, and thus preserves 
their excitability, the following experiment was made. 
Exp. ig. All the nerves supplying one of the hind limbs 
of a frog were divided, so that it became completely paralytic. 
The skin was removed from the muscles of the leg, and salt 
sprinkled upon them, which, being renewed from time to 
time, excited contractions in them for twelve minutes; at the 
end of this time they were found no farther capable of being 
excited. The corresponding muscles of the other limb, in 
which the nerves were entire, and of which consequently the 
animal had a perfect command, were then laid bare, and the 
salt applied to them in the same way. In ten minutes they 
ceased to produce any contractions, and the animal had lost 
the command of them. The nerves of this limb were now 
divided, as those of the other had been, but the excitability of 
the muscles to which the salt had been applied was gone. Its 
application excited no contraction in them. It sometimes 
happens, while the nerves of the limb are entire, that the 
voluntary efforts of the animal prevent the contractions usu- 
ally excited by the application of salt. This experiment was 
repeated in the same manner, and with a similar result. After 
the experiment, the muscles of the thighs in both limbs were 
found to contract forcibly on the application of salt. It excited 
equally strong contractions on both sides. 
It is remarkable, that in this experiment, the excitability 
of the muscles whose nerves were entire, was soonest ex- 
hausted. In the repetition of the experiment, this was the 
case to a still greater degree, the muscles, whose nerves were 
entire, losing their excitability in about one half of the timg 
required for exhausting the other. 
