The pancreas of the dog secretes continuously in the absence of the secretin mechanism and the absorption of se-cretagogue. The juice secreted continuously under such conditions amounted to from 0.2 to 9 cc. per hour in 8 animals. The amount secreted during 24 hrs. varies widely; the maximum obtained was 147 cc. Normal saline solution (12 cc. per min.) and 6% glucose solution (at a rate of 1.6 g. glucose per kilo per hr.) intraven. did not significantly alter the pancreatic response. This does not imply that in the presence of dehydration normal saline will not augment the rate of secretion. The mechanism responsible for the production of the continuous secretion was not determined. Yet, the data obtained by stimulating the degenerating vagus nerve, which contains secretory fibers, show that the secretion observed may be accounted for by the effect of excitatory secretory nerves on the pancreas. A "psychic secretion" of pancreatic juice may be obtained in the absence of the secretin mechanism and the absence of the passage of gastric juice into the intestine. The quantity of juice secreted in response to sham-feeding is small, which is also known to be true when the ordinary pancreatic fistula dog is sham-fed. Eserine, like pilocarpine, usually stimulates the secretion of the pancreas slightly and causes the production of a juice rich in nitrogenous substances. The results indicate that acetylcholine may effect either the excitatory or inhibitory mechanism of pancreatic secretion, but tends to select the inhibitory mechanism when given after eserine. On stimulating the degenerating vagus nerve, at a time (3-6 days) when the inhibitory fibers to the heart have lost their irritability, pancreatic secretion is usually increased. Under this condition when the nerve is stimulated after the injection of secretin an additive or a potentiated secretory response may be observed. However, in 8 of 14 exps. inhibition of the response to secretin occurred, indicating that inhibitory fibers for the pancreas were still present in the degenerating nerve. Anrep''s observation that stimulation of the peripheral, freshly sectioned, end of the vagus inhibits the secretory response to secretin, was confirmed.