PRACTICAL EXERCISES 1147 



One of each pair of rats had a growing tumour produced by 

 transplantation, while the other had been proved resistant to the 

 same type of tumour. No evidence of the passage of an antibody 

 was found in this case. 



PRACTICAL EXERCISES. 



i. Contractions of Isolated Uterine Rings. Kill a female adult 

 rabbit by striking it at the back of the neck. A rabbit which is not 

 pregnant, or only at the beginning of pregnancy, should be selected. 

 Open the abdomen, and carefully remove the uterus. While separating 

 the organ from the broad ligament and vagina, support the horns of 

 the uterus on soft threads. Ligature the vagina before cutting through 



Fig. 489. Contractions of Rabbit's Uterus Ring. At 41 Ringer's solution was 

 replaced by adrenalin solution, 1:1,000,000. Time-trace, half-minutes. 



it, and cut below the ligature, which can then be used to manipulate 

 the uterus. Do not pinch the uterus with forceps, and handle it as 

 little as possible. At once place it in Ringer's or Tyrode's solution* 

 (p. 200), kept at body temperature (38 C.) in a small beaker immersed 

 in a water-bath, as in the experiment on the contraction of isolated 

 intestine (p. 452). Cut a ring of tissue about li centimetres in width 

 from one of the horns. Tie a loop with a fine silk thread at each end 

 of a diameter of the ring, pinching up a little of the external coat to do 

 so with fine forceps. Make the arrangements necessary for recording 

 contractions of the circular fibres of the ring while it is immersed in a glass 

 cylinder in the bath, as in Experiment i, p. 452. Connect another tiegment 



* Tyrode's solution contains 0-8 gm. NaCl, 0-02 gm. KC1 0-02 gm CaCl 

 o-oi gm. MgCl 2 , 0-005 gm. NaH 2 PO 4 o-i gm. NaHCO 3 and OT gm. dextrose 



ttrt f r\r\ r* / *->-f Airo'f/ir' 



in too c.c. of water. 



