326 R. R. BENSLEY 



phate. In the secretin animals, however, it was not considered 

 desirable to bring the pancreas absolutely to rest by this method 

 before injecting secretin, because it might affect the action of 

 the secretin itself. Moreover, if the claims were true that activ- 

 ity increased the number of islets, this effect should be exaggerated 

 by using for stimulation animals in which a slow continuous 

 secretion had been going on, and in which the initial number of 

 islets might on this basis be expected to be high. 



In order to test the question of continuous secretion in the 

 guinea pig it was found necessary not only to withdraw food but 

 to isolate the animals in cages having a grating some distance 

 above the floor, for guinea pigs readily eat their own faeces, and 

 so keep the stomach partly filled, and they will secure this sort 

 of food even on a grating if other animals are with them. Animals 

 kept thus without food, however, show the stomach practically 

 empty at the end of twenty-four hours. In these animals, if a 

 cannula be introduced into the duct, a very slow pancreatic secre- 

 tion manifests itself, but the pancreas quickly responds to dog 

 secretin introduced intravenously, or subcutaneously. 



Bayliss and Starling ('03) have shown that in addition to the 

 intravenous method of administering secretin the latter is active 

 if introduced subcutaneously or into one of the serous cavities. 

 The response in the latter case was, however, much less than with 

 the intravenous method. In experimenting on guinea pigs I 

 tried for this reason, at first, to use the intravenous method, but 

 did not succeed in keeping a single animal alive under stimulation 

 for a sufficient number of hours to justify the expectation that a 

 condition of exhaustion sufficient to test Dale's claims had been 

 produced. I was therefore compelled to resort to the subcutane- 

 ous method, which had the advantage of permitting a much larger 

 dosage with secretin. For this purpose secretin made from dog 

 intestine according to the directions of Bayliss and Starling ('02) 

 was injected in doses of 5 cc. under the skin of the belly at inter- 

 vals of one hour, it having been previously determined that the 

 secretion called forth by such a dose lasted for this period of time. 

 The smaller effect of the secretin given in this way is compensated 

 by the much larger dosage which is possible. In this way the 



