LYMPH FOUNDATION 221 



Finally the lymphatics which accompany the portal vein are 

 ligated. This is readily done by separating the vein by blunt dis- 

 section from the accompanying structures, which are then mass 

 ligated. A loose ligature is next placed around the inferior vena 

 cava just above the diaphragm, by making an opening at the 

 posterior end of the 6th or 7th intercostal space on the right side, 

 prying the ribs apart with a strong pair of retractors (meanwhile 

 maintaining artificial respiration) and threading the ligature 

 around the vein by a long aneurysm needle. After applying the 

 ligature, the opening in the thorax should be closed by artery for- 

 ceps, when it will often be found that artificial respiration can 

 be discontinued. Having observed the rate of lymph flow the 

 ligature is tightened for a few moments. Is the effect similar to 

 that of the previous experiment? How is it explained? 



SECRETION OF URINE 



Demonstration 5a. The experiment may be performed on a 

 dog or cat anaesthetized, preferably with urethane (2 grams per 

 kilo given by stomach with an abundance of water). Insert a 

 canula in trachea, a canula in femoral vein for injection, and a 

 canula in the right carotid artery for recording blood pressure 

 with mercury manometer. Expose the left vagus nerve and 

 arrange for stimulating the peripheral end. The secretion of 

 urine is to be observed by counting the drops which issue from a 

 canula inserted into the urinary ducts. In the case of the dog 

 the abdominal cavity may be opened and a slender canula 

 inserted into one of the ureters. In the case of the cat a large 

 canula may be inserted into the urethra by means of an incision 

 made just cephalad of the pubis. The bladder will empty itself 

 through this canula, and if care is taken that the urethral canula 

 does not become blocked all urine flowing from the ureters will 

 pass through this canula without accumulating in the bladder. 



Do not attempt to repeat the observations because the secretion 

 will not continue indefinitely. Observe the following: 



(A) The Effect of Blood Pressure upon the Secretion of Urine. 



1. Determine the normal blood pressure and rate of urine flow. 



2. Inject 0.5 c.c. 1, 10,000 Adrenin into the femoral vein. 



