INTERNAL SECRETIONS. 



with the inferior vena cava. A little above the angle formed by 

 these two veins and closely hugging the inferior vena cava, the left 

 suprarenal capsule will be seen. 



This is a yellowish-white oval body, lying behind the perito- 

 neum. Its blood supply is variable. There are generally one large 

 artery and vein entering the hilum of the gland, and these must be 

 tied before the gland is excised. 



With small blunt hooks and a blunt-pointed seeker tear through 

 the overlying peritoneum. Separate the gland from its surround- 

 ings slowly and carefully, being especially careful to avoid injury 

 to the inferior vena cava. 



Remove all cotton pads from the abdominal cavity. Bring the 

 muscles and peritoneum together with one row of silk sutures, and 

 the skin with another row of sutures. Cover the wound with some 

 antiseptic powder and apply a gauze bandage. Place the rabbit in 

 its cage and observe it carefully twice a day for the first two days 

 and then make daily observations. At the end of two weeks the 

 remaining gland may be removed. In the mean time make an ex- 

 tract of the gland as described below. 



2. Weigh the suprarenal which you have removed. Grind it in a 

 mortar with fine clean sand and a little o.y-per-cent NaCl solu- 

 tion. Add of the salt solution enough to equal ten times the 

 weight of the gland. Transfer to a tightly stoppered bottle and 

 place in the incubator at 30 C. for fifty-six hours. Strain through 

 muslin and filter through paper. One part of this extract will be 

 equivalent to y 1 ^ of the fresh gland. 



3. (a) Prepare another rabbit for a blood-pressure experiment. 

 Isolate both vagi and secure them with untied ligatures. Prepare 

 one jugular vein for injection. Take a normal blood-pressure 

 tracing. While the tracing is being recorded, inject into the jug- 

 ular enough of the suprarenal extract to be equivalent to -f^ 

 of the fresh gland. Note the effect on the heart-beat and on 

 blood pressure. What is the duration of the effect of the in- 

 jection ? 



(b) Repeat the injection, and immediately after cut both vagus 



10 [ US ] 



