THE presence of sympathomimetic activity in adrenergic nerve tissue has been demonstrated by several authors1. The active substance later was shown to possess the characteristic biological and chemical properties of noradrenaline2. A comparison of the relative contents of noradrenaline in splenic nerves (10-20 µgm. per gm.) and the spleen (2-4 µgm. per gm.) suggests that the transmitter is accumulated in the terminal parts of the nerves. Certain substances, such as acids, detergents and digitonin, which release catechol amines from adrenal medullary cell granules3, also release the adrenergic transmitter from a perfused organ4. Moreover, since the adrenergic nerves may be regarded as homologues of the adrenal medullary cells, it may be expected that their specific action substance is similarly stored.