88 THE WORK OF THE DIGESTIVE GLANDS. 



beginning of the experiment, and also that during the experiment no 

 impulse comes into play, which of itself, apart from mechanical excita- 

 tion, could excite the glands to secretion. Nor have we any proof that 

 observers formerly waited for hours before commencing the experiment, 

 and convinced themselves that the gastric glands had ceased working. On 

 the contrary, we have not the slightest evidence to indicate that the 

 authors had attempted to guard against accidental psychical stimulation 

 of the glands a matter which we have seen is of considerable difficulty. 

 And some dogs are so easily excited in this way that it is almost impos- 

 sible to bring their glands to rest, or at least it is necessary to wait for 

 hours. The experimenter must strain his whole attention to preserve 

 such an experiment free from objection. It is only necessary that some 

 food be near the dog, or that the hands of the attendant who has 

 prepared the food should smell of it, or that some other similar 

 circumstance should come into play, and the glass tube, quite undeser- 

 vedly, will be made answerable for the excitation of the gastric glands. 

 As you have just seen, both of our conditions have been fulfilled on 

 the dog before you, and the result of the experiment stands in irre- 

 concilable contradiction to those of the laboratory and lecture experi- 

 ment of former times. 



The importance of the experiment, which I have already dwelt upon, 

 justifies me in making still further demands upon your attention in 

 order to show you two modifications of it. Nobody has as yet said, with 

 regard to mechanical stimulation, that in order to obtain results, the 

 mechanical agency must simultaneously come into contact with numerous 

 points of the inner surface of the stomach. But in order to meet this 

 possible objection I will now show you two new modifications. Again, 

 a similar dog is used, that is to say, one on which both gastrotomy and 

 lesophagotomy have been performed. The stomach has been washed 

 out clean and is at present in a state of complete rest. Into the 

 fistula I bring a thick glass tube containing a number of small open- 

 ings (2 to 3 mm. diameter) at its rounded end. The other end 

 of the tube is connected with a glass ball containing tolerably coarse 

 sand. Leading into the ball is a second tube, with which an india- 

 rubber pump can be connected and a blast of sand blown through. 

 By rhythmic compression of the india-rubber ball I inject sand with 

 considerable force into the stomach, and this play is kept up for ten to 

 fifteen minutes ; nevertheless, we see no trace of gastric juice. The 

 sand falls out again between the side of the cannula and the glass tube, 

 and it is either dry or scarcely moistened, but in no case is it able to 

 turn blue litmus red. And yet we are here dealing with a strong and 

 widely diffused stimulus. Look for a moment at the performance of 

 the bellows outside the stomach. From every opening of the tube 



