The authors examined the change in EKG in rabbits before and after the irritation on the labyrinth and obtained the following results:
A) In normal rabbits.
1) The duration of P-P, P-Q and Q-T is prolonged.
2) while the height of the P-wave decreased and that of the R-wave and T-wave increased.
B) In vagotomied rabbits.
1) The prolongation of P-P, P-Q and Q-T can not be seen this time.
2) The height of the R-wave is reduced and that of the T-wave increased.
C) In sympatheticotomied rabbits.
1) The prolongation P-P, P-Q and Q-T can be ssen distinctly.
2) The height of the T-wave decreased.
From these results it is appearent that labyrinth irritation stimulate both vagus and sympathetic, but in normal conditions vagus excitation is too strong to allow the symptom of sympathetic irritation appear.