Spontaneous contractions of the stomach of the cat fetus are already present in fetuses of 58 mm. body length. Both peristaltic and antiperistaltic movements can be observed. Acetylcholine and pilocarpine raises the tonus and in some instances increases the rate of contractions. The effects of these drugs are abolished by atropine. Atropine by itself has a double — inhibitory and excitatory— effect. Adrenaline in small doses stimulates and in large doses inhibits the motility. Ergotamine paralyzes the effect of adrenaline. The usual effect of adrenaline after acetylcholine is one of antagonism but sometimes the 2 drugs act synergistically