140 



F. A. BA1NBRIDGE AND H. H. DALE. 



when the abdominal walls are freely opened. We have, in fact, deliber- 

 ately allowed contact between a vigorously contracting stomach and the 

 gall-bladder, under such conditions, without being able to detect any 

 indication of the contractions upon the gall-bladder record. 



(3) Upon the effect of changes in the volume of the liver we intend 

 to lay some stress, as it has been completely left out of consideration in 

 earlier investigations. We found it essential to eliminate this influence 

 either by separating the gall-bladder from the liver, or by a dissection 

 which gave the liver perfect freedom of expansion. 



Another precaution taken was the registration of the blood-pressure 

 simultaneously with the contractions of the gall-bladder. This is 

 omitted in the tracings unless there is special reason for giving it. 



I. SPONTANEOUS CONTRACTIONS. 



A record of. the volume of the gall-bladder, obtained as above 

 described, shows spontaneous variations, which occur rhythmically at the 

 rate of 1 to 3 per minute (Fig. 1) ; though noticeable even at the 

 beginning of an experiment, this rhythm is usually more obvious after 

 section of the splanchnic nerves, and still more so after the injection of 



Fig. 1. 



Fig. 2. 



Fig. 1. x f. To show the intrinsic rhythm of the gall-bladder. The animal was under 

 curare, the gall-bladder separated from the liver. Vagi and splanchnics cut. 



Fig. 2. x^f. Curare. Vagi and left splanchnic cut. Pressure on balloon in gall-bladder 

 raised to 50 cm. of water, the exaggerated rhythm resulting. Eight splanchnic cut at 

 /.', section causing momentary inhibition of rhythm. The small undulations in this 

 and succeeding tracings were produced by the artificial respiration. 



