INHIBITORY NERVES OF THE PANCREAS. C.I 



administering physostigmin to the animal, a drug which strongly excites 

 the activity of smooth muscle. But absolutely no inhibition, rather an 

 augmentation of the secretion made its appearance. Finally, by a 

 careful preparation of the nerves, some branches were discovered whose 

 excitation caused a secretion without any latent period, almost as 

 promptly as the chorda tympani expels saliva. From the latter fact we 

 must conclude that in the branches mentioned, the secretory fibres of 

 the pancreas have been anatomically separated from the inhibitory, and 

 that the purely secretory nerves, on artificial stimulation, call into play 

 the activity of the organ without any latent period. Finally, Dr. 

 Popielski succeeded also in isolating branches of the vagus which only 

 inhibited and never called forth a secretion. If such inhibitory nerves 

 exist, it is easy to understand their reflex excitation both under normal 

 conditions as well as during the operations. Nor is the possibility 

 excluded that reflex inhibition extends also to the secretory centres for 

 the pancreas. 



The observations here given furnish an explanation of all the failures 

 and difficulties which the earlier investigators of the innervation of the 

 pancreas had to fight against. Why, for example, did Heidenhain only 

 obtain a positive result in a few experiments on excitation of the 

 medulla oblongata ? To say nothing of the inhibitory effects of the 

 operation ; he called forth by excitation of the medulla, a strong contrac- 

 tion of the vessels and an alteration of cardiac activity. Moreover, he 

 excited at the same time the antagonists of the secretory fibres. 



You have, of course, already noticed how similar the nervous con- 

 nections of the stomach and pancreas have turned out to be ; the 

 innervation of the one is in every respect a copy of the other. 

 Consequently it is permissible to fill up gaps in our knowledge of one 

 of the schemes of innervation by analogy from the other. We cannot 

 doubt, for example, that secretory fibres for the stomach are present 

 not only in the vagus but also in the sympathetic. 



In conclusion, a few words concerning the experiment of the two 

 French authors on the stomach of the beheaded criminal. We have 

 seen how extremely delicate the digestive glands are, and cannot, there- 

 fore, easily believe that the authors were able to set up a true secretory 

 effect from excitation of the vagus forty minutes after the organ had 

 been deprived of blood. 



I think I may now rest satisfied, after all that has been said and 

 shown to you, that the existence of secretory nerves to the stomach and 

 pancreas will appear to you just as real and unquestioned as those for 

 the salivary glands in the classic and universally known chorda tympani. 

 It need hardly be said that, in addition to these special nerves, vaso-motor 

 nerves constrictor and dilator also pertain to the glands. 



