1. Two atropine-resistant response-components of nervous origin have been detected in plexus-containing preparations of the longitudinal muscle from the guinea-pig ileum, by alternate field stimulation with equal numbers of pulses at 50 Hz (response A) and at 5 Hz (response B). With trains of ten or more pulses, response A is always larger than B; the ratio of A/B (1·2-21·3) is subject to animal variation.