Here is that incident from Treasure Island by Robert Louis Stevenson, where Billy Bones had a 'minor' heart attack or a stroke (according to R.L. Stevenson).
To give a little background about Billy Bones, he was a pirate, a toughened and hardened person who has gone through the deadly and unethical ordeals of life. He was an alcoholic and used to drink rum a lot. Dr. Livesey had previously warned him of taking any rum at all. But its quite a daunting task to let go a life long bad habit. Another thing worthy to be mentioned is that (to me it felt) Billy Bones had a very short temper which is indicative that he is a very likely candidate of high blood pressure.
In one incident, Billy Bones had a fight with an old foe of him. His foe escaped after collecting some major injuries caused by Billy Bones namely known as the Captain in Admiral Benbow inn. As the fugitive left the vicinity, Billy Bones gasping called out for rum and immediately he fainted.
I heard a loud fall in the parlour, and running in, beheld the captain lying full length upon the floor. ...He was breathing very loud and hard, but his eyes were closed and his face a horrible colour.
Jim called in Dr. Livesey downstairs who was treating Jim's father upstairs.
“Oh, doctor,” we cried, “what shall we do? Where is he wounded?”
“Wounded? A fiddle-stick's end!” said Dr. Livesey. “No more wounded than you or I. The man has had a stroke, as I warned him... I must do my best to save this fellow's terribly worthless life; Jim, you get me a basin.”
When I got back with the basin, the doctor had already ripped up the captain's sleeve and exposed his great sinewy arm. It was tattooed in several places...
“Prophetic,” said the doctor, touching this picture with his finger. “And now, Master Billy Bones, if that be your name, we'll have a look at the colour of your blood. Jim,” he said, “are you afraid of blood?”
“No, sir,” said I.
“Well, then,” said he, “you hold the basin”; and with that he took his lancet and opened a vein.
My question is about Dr. Livesey's little surgery. R.L. Stevenson writes after this 'surgery',
A great deal of blood was taken before the captain opened his eyes and looked mistily about him.
It almost had an immediate positive effect on the patient. My question is about Dr. Livesey's little surgery. What did he do here? Was it any form of valid treatment?