I will allow Plato to tell the remainder of the story, for I cannot possibly do it justice.
“Go,” said Socrates, “and do as I say.”
Crito, when he heard this, signaled with a nod to the boy servant who was standing nearby, and the servant went in, remaining for some time, and then came out with the man who was going to administer the poison. He was carrying a cup that contained it, ground into the drink.
When Socrates saw the man, he said: “You, my good man, since you are experienced in these matters, should tell me what needs to be done.”
The man answered: “You need to drink it, that’s all. Then walk around until you feel a heaviness in your legs. Then lie down. This way, the poison will do its thing.”
“I understand,” he said, “but surely it is allowed and even proper to pray to the gods so that my transfer of dwelling from this world to that world should be fortunate. So, that is what I too am now praying for. Let it be this way.”
And, while he was saying this, he took the cup to his lips and, quite readily and cheerfully, he drank down the whole dose. Up to this point, most of us had been able to control fairly well our urge to let our tears flow; but now, when we saw him drinking the poison, and then saw him finish the drink, we could no longer hold back…
So, he made everyone else break down and cry—except for Socrates himself. And he said: “What are you all doing? I am so surprised at you. I had sent away the women mainly because I did not want them to lose control in this way. You see, I have heard that a man should come to his end in a way that calls for measured speaking. So, you must have composure, and you must endure.”
Then, he took hold of his own feet and legs, saying that when the poison reaches his heart, then he will be gone. He was beginning to get cold around the abdomen.
Then he uncovered his face, for he had covered himself up, and said— this was the last thing he uttered— “Crito, I owe the sacrifice of a rooster to Asclepius; will you pay that debt and not neglect to do so?”
“I will make it so,” said Crito, “and, tell me, is there anything else?”
When Crito asked this question, no answer came back anymore from Socrates. In a short while, he stirred. Then the man uncovered his face. His eyes were set in a dead stare. Seeing this, Crito closed his mouth and his eyes.
-Plato, Phaedo (Translation by Gregory Nagy)