Apparent differences between the effects of hyoscine in vivo and in vitro on the responses of chicken oesophagus to nerve stimulation.

1. In chickens anaesthetized with sodium pentobarbitone, stimulation of a vagus nerve produced contractions in the muscles in the pre-crop oesophagus which were only partly antagonized by hyoscine.2. The effect of hyoscine in an isolated preparation of chicken oesophagus responding to nerve stimulation was shown previously to be similar to that now found in the in vivo preparation.