180 INFLUENCE OF THE 



a short piece of the intestine into which the pancreatic duct opened, 

 and which was then, after splitting open, attached to the abdominal 

 wall, the continuity of the intestine having of course been restored 

 by suturing together the two ends of the intestine after the removal 

 of the short piece containing the opening of the pancreatic duct. 

 Pawlow improved upon this by merely cutting out a small oval 

 patch of the intestinal wall around the entrance of the pancreatic 

 duct, and then reclosing the intestine, which was only slightly 

 narrowed by this procedure. The small oval patch so removed 

 was then implanted on the outside of the muscular abdominal 

 wall, so that the pancreatic secretion was now poured out to the 

 exterior. 



By careful nursing, adaptation of the food, and administration 

 of sodium bicarbonate so as to make good the loss of alkali due 

 to the flowing away of the secretion to the exterior, dogs with 

 such fistulse could be preserved alive and in good health for a long 

 time, and after recovery could be used for the study of the 

 effect of alterations in the nature of the food upon the 

 amount and quality of the pancreatic secretion, and for the 

 investigation of the effects of the gland nerves upon the process 

 of secretion. 



In such an animal, the preliminary procedure to studying the 

 effect of stimulation of the vagus 'upon the secretory process is 

 to dissect out a portion of the nerve in the neck and cut it, attach- 

 ing a ligature to the peripheral end. The nerve is then preserved 

 under the skin for a period of four days, in order to allow time 

 for the cardiac fibres to degenerate. After the lapse of this time, 

 the stitches are removed and the nerve stimulated with slow 

 induction shocks. As a result of stimulating, it is found that 

 after a latent period of about three minutes a flow of pancreatic 

 juice commences and gradually increases in quantity. On stopping 

 the stimulus the flow does not instantly stop, but continues in 

 decreasing quantity for a period of four or five minutes from the 

 cessation of the stimulus. Positive results were also obtained 

 by Pawlow by the use of the so-called " acute " method, provided 

 the spinal cord was cut to avoid reflex inhibition from the operative 

 procedures, and the vagus was stimulated below the cardiac nerves 

 so as not to produce disturbance of the heart and circulation. 

 The order of procedure being tracheotomy, severance of cervical 

 spinal cord below medulla, artificial respiration, opening of thorax 



