The action of adrenalin

In further illustration of Langley's generalisation that the effect of adrenalin upon plain muscle is the same as the effect of exciting the sympathetic nerves supplying that particular tissue, it is found that the urethra of the cat is constricted alike by excitation of the hypogastric nerves and by the injection of adrenalin. The sacral visceral nerves, on the other hand, relax the urethra of the cat. But while the hypogastric nerves relax the tension of the bladder wall in the cat, they do not cause any similar change in the dog, monkey, or rabbit: and though, as is well known', adrenalin inhibits the cat's bladder, this reaction is the exception in the mammalian bladder, for adrenalin' does not produce any change in those of the three animals named above. I have repeated the experiment of clean excision of the suprarenal glands and find that the animal, when moribund, exhibits symptoms that are referable to a hindrance of the activities of those tissues especially that are innervated by the sympathetic. They lose their tone; and may even fail to respond to electrical stimulation of the sympathetic nerves. The blood-pressure falls progressively, and the heart-beat is greatly weakened. And at the latest stage previous to death, though the nerves of external sensation and those controlling the skeletal muscles are perfectly efficient, the sympathetic nerves exhibit a partial paralysis of such a nature that nicotine, when injected, is unable to effect through them a rise of blood-pressure or to cause dilatation of the pupil.