PSYCHIC EFFECT AND PANCREATIC SECRETION. 123 



it. Under their influence it is emulsified and split, and it is a fact 

 that after one or two hours the emulsified fluid becomes acid. Tt 

 is also possible, in the case of an empty stomach, that the duodenal 

 cavity may expand at the expense of the former. The second remark 

 concerns the sleeping of the animal during the experiment. As I have 

 previously stated, sleep does not exercise the least influence on the 

 secretory work of the gastric glands. With regard to the pancreas, 

 however, the distinct statement went forth from the laboratory some 

 years ago that sleep almost completely arrests the secretion of pan- 

 creatic fluid, even when it is in full progress. Further observations 

 have shown that this was an error, and the origin of the mistake 

 is not without interest. The investigator who made it was, apparently, 

 perfectly right. When the animal slept the secretion abruptly declined 

 and fell to nil. But why? Instead of the connection which was 

 assumed, it was found that a purely extraneous circumstance explained 

 the relationship between the sleep of the animal and the arrest of 

 the flow. The dog in this case was retained in a frame by a special 

 arrangement of leather supports which we named " boots." When the 

 animal slept, it naturally assumed an easy, passive position, and allowed 

 its body to hang in the straps of the boot. In this way the skin was 

 differently stretched, in many parts being displaced from its ordinary 

 position, and at the same time the duct of the pancreas which passes 

 through it was kinked and pressed upon. Thus a distinct but purely 

 extraneous and accidental connection came to exist between the sleep- 

 ing of the dog and the arrest of the pancreatic flow. This fact is 

 further evidence of the necessity for constant watchfulness over the 

 minutest details in the performance of physiological experiments. 



We shall now pass on to the other exciting agencies which proved to 

 be effective in the case of the secretion of gastric juice. Will they not 

 also have an influence on the pancreas ? I refer to the psychic effect, 

 together with that of water and also of extractive substances. Theo- 

 retically, the answer might be either a positive or a negative one. If 

 the feeling of appetite and the presence of water are necessary to 

 ensure a beginning of gastric secretion, the same might also apply to 

 the flow of pancreatic fluid, although the secretion is essentially depen- 

 dent (through the acid) on gastric digestion. In affections of the 

 stomach the pancreas might remain without its chief exciter, but we 

 know of pathological conditions where the hydrochloric acid was absent 

 from the gastric juice for months, and yet digestion as a whole pro- 

 ceeded tolerably well. In the interests, therefore, of a greater degree 

 of independence for the pancreas, we should be inclined to admit the 

 activity of the above-named exciters. But facts must decide the case. 

 We have intentionally deferred this question till near the end of the 



