CHEMICAL EXCITANTS OF PANCREATIC SECRETION. 125 



tine, and also for pancreatic secretion, into action, while the impulse is 

 not sufficient to excite the more inert gastric glands, which, as we know, 

 have a longer latent period. It is, moreover, possible that the centre 

 for the nerves of the pancreas in agreement with the fact that the 

 gland belongs to the abdominal set of digestive organs should be more 

 or less closely associated with the centre for the motor nerves of the 

 intestine. The psychic excitation of intestinal movements is, however, 

 a universally recognised fact, and has even become a byword when, for 

 instance, it is said that in severe hunger the stomach yearns. In any 

 case, the question of psychic excitation of the pancreas requires further 

 investigation. 



Similar considerations to those in the case of psychic excitation have 

 to be borne in mind with regard to the relationship which exists between 

 Avater and pancreatic secretion. When water is poured into the stomach 

 the result is a secretion of pancreatic juice. But how ? Is it because it 

 independently excites the gland, or because it has led beforehand to 

 acidification of the gastric contents? In the experiments to decide this 

 question the same method was adopted (Dr. Damasking as in the case of 

 oil. When 150 c.c. of water are poured unnoticed into the stomach of a 

 dog, the glands of which are resting, one sees after two or three minutes 

 that the secretion of pancreatic juice either begins or becomes distinctly 

 increased. If one waits for a minute or two longer, and then empties 

 the stomach, some water, or rather a neutral or possibly alkaline fluid, 

 is generally still found. Occasionally the secretion of pancreatic juice 

 continues for a time after the emptying of the stomach, although no 

 secretion whatever may have occurred in the latter, or may only have 

 appeared after the lapse of ten minutes. The conclusion is clear and 

 free from objection, namely, that water is an independent and direct 

 exciter of the nervous mechanism of the pancreas. 



Finally comes the question, How do other chemical excitants of the 

 gastric glands behave, namely, those which we have found in the 

 extractives of flesh ? The experiments on this point were arranged in 

 the same way as those with pure water, and gave precisely the same 

 results. When solutions of meat extract were poured in, the secretion 

 began after the same length of time as with water, and was in no case 

 greater. 



If we now sum up these facts, we are in a position to say that there 

 are some excitants common to the gastric glands and to the pancreas. 

 Amongst these probably the psychic effect, the strong craving for 

 food and water, is to be included. But, in addition, both organs have 

 their own specific stimuli ; for the gas-trie glands, the extractive sub- 

 stances of meat ; and for the pancreas, acids and fat. 



We must, however, dwell a little longer on the inhibitory phenomena 



