626 APPENDIX 



killed frog. Tie a ligature about the pyloric end. Make an open- 

 ing into the stomach at the cardiac end and by means of a pipette 

 fill the stomach with 0.7% salt solution. Tie a second ligature so 

 as to close the opening into the stomach, and cut the stomach 

 from the body. 



By means of a thread attached to the pylorus hang the stomach 

 so that the cardiac end just dips into a solution of 0.7% sodium 

 chloride and 0.1% sodium carbonate. Look for the peristaltic 

 waves passing over the stomach. Note the time required for a 

 single wave to pass, and the number of waves per minute. This 

 observation is more striking in early fall or late spring than in 

 mid winter when the frogs are in the midst of hibernation. 



Absorption from Stomach and from Small Intestine. Lay bare 

 the stomach and intestines of a large turtle whose brain has been 

 destroyed and plastron removed without loss of blood. 



Using great care to avoid tearing the mesentery (supporting 

 membrane of stomach and intestines) find the points of union of 

 stomach and intestine and of intestine and rectum. Tie stout 

 threads tightly about these points. 



Find the junction of esophagus with stomach. Place a thread 

 about the junction ready for tying. Make an opening into the 

 esophagus above the thread. Introduce into the stomach through 

 this opening by means of a graduated pipette, water to moderate 

 distension. Note the exact amount of water introduced. With- 

 draw the pipette and tie off the junction with care that no water 

 escapes. 



Place a thread ready for tying about the intestine one-half inch 

 below the one previously tied about the point of union of stomach 

 with intestine. Introduce a known amount of water into the in- 

 testine through a hole made just above the thread last placed. 

 Tie this thread. Allow absorption to proceed for one hour. At 

 the expiration of the period of absorption cut between the threads 

 tied about the upper end of the intestine and dissect out the 

 stomach and intestine. Empty each into a separate vessel. Com- 

 pare the amount of water introduced with the amount recovered. 

 If the mesentery is intact and the circulation good the intestine 

 will be virtually empty at the end of an hour. The stomach will 

 contain practically the entire amount introduced. Similar tests 

 may be made with solutions of -dextrose. 



