ADRENALS 



663 



the latent period of the secretion is so short that the reaction follows 

 the commencement of stimulation of the nerve after a time-interval 

 sensibly the same as when it is elicited by the corresponding amount 



Fig. 213. -20, Pocket Experiment with Stimulation of ^Right Splanchnic in Abdo- 

 men after Section of Both Splanchnics. 21, repetition of 20, but with a shorter 

 time of stimulation. The epinephrin rise of blood-pressure after 20 is consider- 

 ably greater than after 21. Time-trace, half-minutes (f reduction). 



of adrenalin injected at the level of the adrenal veins. Even when 

 the glands have ceased to respond to stimulation of the nerves, 

 epinephrin can still be liberated into the blood by massaging the 

 glands with the fingers (Fig. 214). 



Fig. 214. Showing the Effect of Massage in Liberating Epinephrin from the Left 

 Adrenal whose Nerves had been Cut Five Weeks before. 27, cava pocket with 

 massage, the left adrenal vein being open to the pocket. 47 to 49, pocket with 

 massage, the left adrenal vein having been closed at 45 and opened at 48, after' 

 closure of the pocket. Massage begun at 45-A, stopped at 46. Blood-pressure 

 tracing from carotid artery. Time-trace, half-minutes (reduced to $). 



A centre for epinephrin secretion seems to exist in the upper part 

 of the thoracic region of the spinal cord. After section of the cord 

 in the cervical region, even as low as the level of the last cervical 

 segment, the secretion persists, but it is abolished when the cord is 

 divided at the third or fourth dorsal segment. 



