ACIDS EXCITE A FLOW OF PANCREATIC JUICE. 113 



We begin with a form of stimulus which aroused the attention 

 'of the laboratory in a very striking manner, just as did the dis- 

 covery of the p>ychic excitation of the gastric glands. In the search 

 for pancreatic stimuli we (Dr. Becker) tested, for particular 

 reasons, on the one hand, the effects of solutions of neutral 

 and alkaline salts of the alkali metals ; on the other hand, water 

 saturated with carbon dioxide gas. It resulted that a species of 

 antagonism was found to exist between these substances in their 

 effects upon the pancreas. The saline solutions proved to be weaker 

 excitants of pancreatic juice than water, the carbon dioxide distinctly more 

 energetic. These results directed our attention to the effects of acids, 

 and we may now proceed to the important initial experiment of our in- 

 vestigations iipon this subject. The dog which I bring before you possesses 

 a permanent pancreatic fistula. As you see, the secretion at present 

 is hardly worth mentioning, two to three drops in the minute, and even 

 this is quite easily accounted for : the animal was fed fifteen 

 hours ago. I introduce 1">0 c.c. of half per cent, solution of hydro- 

 chloric acid by means of the sound into the stomach. The dog remains 

 perfectly still and makes no protest whatever against the procedure. 

 Two to three minutes after the injection you notice that the drops fall 

 faster. We can already count twenty-five in the minute, and the flow 

 grows stronger and stronger. In order to meet the objection that water 

 or the influence of fluids generally, acts here as the exciting agency, I 

 bring into the stomach 500 c.c. of lime-water, and you see not only that 

 the secretion does not increase, but, on the contrary, grows weaker and 

 weaker, indeed almost stops. This powerful influence of acids upon the 

 pancreas is one of the most securely established facts in the whole 

 physiology of the gland. The acids are such strong stimulants to pan- 

 creatic flow that by their means one can excite the activity of the gland 

 more effectively than by any other; so much is this the case, that in the 

 laboratory, the effect of acids has become a crucial test of the normal 

 condition of the alimentary canal in this respect. To illustrate the in- 

 tensity of the juice-secreting influence of acids, I give here an example 

 taken from the work of Dr. Dolinski, who had the investigation in 

 hand. 



The dog was fed twenty-two hours beforehand, and pancreatic juice 

 no longer flowed. Two hundred and fifty c.c. of hydrochloric acid of the 

 strength of the gastric juice were poured, by means of the sound, into 

 the stomach. The quantity of juice secreted every five minutes is shown 

 below : 



(i'O C.C'. 



'.IT, ,. 

 9-5 

 9-5 , 



0-4 c.c. 



2-i .. 



