B y G . W . H a r r is a n d D o r a J a c o b s o h n

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Some days after parasympathetic decentralisation of the submaxillary gland, brought about by cutting the chorda tympani, the secretory cells of the gland show an increased sensitivity t o chemical agents. This was first demonstrated by MAEVSKY (1923), using adrenaline as a secretory stimulus. The "paralytic secretion'' of saliva appearing after cutting the chorda (CLAUDE BERNARD, 1864) is very likely evoked by adrenaline (noradrenaline) acting on the supersensitive gland cells, since it is observed only under experimental conditions causing a sympathetic hyperactivity or an augmented discharge of hormone from the adrenal medulla (EMMELIN and MUREN, 1950).Injection of atropine renders the gland cells insusceptible t o parasympathetic impulses, and treatment of the submaxillary gland with atropine over a period of several days gives rise to a supersensitivity of the gland cells to chemical stimuli just as does exclusion of parasympathetic impulses by section of the chorda tympani. A cat treated for some time with atropine exhibits a "paralytic secretion'' under the same experimental conditions as a cat with severed chorda tympani. On the other hand, if a submaxillary gland deprived of parasympathetic impulses through chorda section is supplied witch secretory stimuli by repeated injections of pilocarpine over a suitable period, no supersensitiv-

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