142 EXPERIMENTAL PHYSIOLOGY 



much more slowly ; for a short time the extent of its contraction is 

 distinctly less. 



The effect of varying the strength of the stimulus is very marked. 

 Weak stimuli primarily affect the auricles, diminishing their rate and 



Fig. 112. — Eesult of the Stimulation of the Left Vagus. 



force, but only secondarily affect the rate of the ventricle. Stronger 

 stimuli may inhibit the auricle almost completely, whilst the ventricle 

 still beats with its original rate and force. The strongest stimuli also 



