premise: the <mask> ganglion of certain Mollusca
hypothesis: the best context for <mask> here is Pertaining to, or invented by, Brown; -- a term applied to a system of medicine promulgated in the 18th century by John Brown, of Scotland, the fundamental doctrine of which was, that life is a state of excitation produced by the normal action of external agents upon the body, and that disease consists in excess or deficiency of excitation.; but not Of or pertaining to the mouth and the stomach.