Mucous branched glands of the soft palate of rodents and the soft and posterior parts of the hard palates of primates have small lumina and little mucus in the inactive stage. The collapsed empty tortuous main excretory ducts have closed orifices. Drying or astringent rinsing of the palate in the lightly anesthesized animal causes droplets of mucus to form on the mucous surface. Glandular changes include an alteration from a columnar to a cuboidal epithelium, rounding and more conspicuous nuclei and wider and filled lumina of the alveoli. The excretory ducts become straight, greatly dilated and filled with mucus. The drying or astringent probably elicits a reflex action which induces great secretion of the alveoli, a filling of the main duct and an exuding of mucus onto the surface. This reaction can be eliminated by the intra-peritonal administration of dibenzyline.