Selective denervation was used to obtain further information about the relative roles of the nerves supplying the gland. Parasympathetic denervation soon caused atrophy in both acinar and granular tubule cells, and a substantial reduction in gland wet weight. The secretory cells had several unusual features, and striated duct cells tended to accumulate glycogen. Three to four weeks after pre-ganglionic parasympathectomy, the parenchymal cells were less abnormal but still smaller than in the control, unoperated gland. Thus, parasympathetic impulses are required to maintain normal parenchymal cells. Chronic sympathectomy caused little or no detectable changes in the secretory cells, and there was no significant change in wet weight. Nevertheless, pre-ganglionic sympathetic axotomy reduced the reflex secretion of acinar mucosubstances in response to feeding. Thus, sympathetic impulses normally contribute to the reflex secretion of acinar mucosubstance from these glands.