INDIFFERENCE TO MECHANICAL STIMULATION. *!) 



numbering considerably more than ten a strong stream of sand is 

 ejected. If you hold your hand against it, you feel quite distinctly, 

 that the grains of sand strike with considerable force. And now, when 

 our experiment is ended, we may convince ourselves by sham feeding, 

 in easy and unquestionable fashion, that the innervation of the dog's 

 stomach is perfectly normal. 



Yet another experiment on a similar dog. Into its empty and rest- 

 ing stomach an india-rubber ball is introduced. This is distended with 

 air by means of a syringe till it is as large as a child's head and main- 

 tained in this condition for a time, afterwards being allowed to collapse. 

 The procedure is kept up for ten to fifteen minutes. During this time not 

 a single drop of juice has appeared from the stomach. The surface of 

 the ball taken out of the organ is everywhere alkaline. And here also 

 subsequent sham feeding shows that the dog is in a suitable condition 

 for the experiment. I must add that in making this observation the 

 dog must not be too hungry, that is to say, must have been fed within 

 ten to twelve hours before, otherwise a psychic excitation of the secretion 

 can readily be induced. 



If one dispassionately regards this question, and if any of our 

 luethods for the study of gastric secretion are reliable, one must be 

 convinced step by step in the laboratory, of the uselessness of 

 mechanical stimulation. In the case of dogs with an ordinary gastric 

 fistula, and failing some special reason, not a drop of gastric juice ever 

 escapes from the stomach other than during the digestive period. 

 How could this be the case if the mechanical stimulus were effective, 

 since the inner rim of the fistula-tube is continuously in contact with 

 the gastric mucous membrane ? The same holds good for the dog with 

 resected stomach. During the experiment a glass or india-rubber tube 

 is brought sufficiently far into the cul-de-sac to catch the juice, and yet 

 not a drop flows through the tube, nor does its inner surface ever 

 become acid, so long as true secretory conditions are absent. Moreover, 

 the tube has tolerably often to be taken out and set light. 



In the ordinary gastric fistula in dogs, when the operation has 

 lasted a long time over a year folds of mucous membrane are often 

 formed in the neighbourhood of its inner orifice, which completely close 

 the tube. In these cases a long thick perforated metal tube has to be 

 passed in deeply, and yet the manipulation of itself never calls forth a 

 secretion. Further, it is a daily occurrence to find in the stomach of 

 the dog, thick rolls of hair, and yet their presence in no way hinders 

 the arrest of the secretion, which occurs when digestion has ceased. 

 Such an occurrence would have been specially obvious in our dog with 

 the isolated stomach, since it was bedded with sawdust in order to guard 

 against maceration of the wound by juice trickling out. Very often 



