The effects of somatic stimuli on the bladder in the cat.

1. Measurement of the intra-vesical pressure in cats during contractions of the bladder was found to be a more reliable method of studying bladder function than the cystometrogram. Under suitable conditions the pressure curves of these bladder contractions were constant and could be examined statistically.2. In the anaesthetized cat cold decreased the pressure developed by bladder contractions and shortened the interval between them. There was no evidence that this effect was reflex in nature.3. In the anaesthetized cat stimulation of the sural nerve sometimes produced contraction of the bladder or increased the pressure developed by spontaneous contractions.4. In the anaesthetized cat stimulation of any hind-limb nerve from muscles with conduction velocities of approximately 50 m/sec inhibited bladder contractions.5. In the acute spinal cat somatic stimuli had no effect on bladder activity.6. In the chronic spinal cat cutaneous stimuli produced reflex contraction of the bladder or the augmentation of a spontaneous contraction. Stimulation of nerves from hind-limb muscles, however, had no effect on bladder activity.7. In the decerebrate cat cutaneous stimuli increased bladder activity, and this was probably ;reflex' in nature. Stimulation of nerve fibres from hind-limb muscles either produced bladder contractions or augmented spontaneous contractions.