Once again we went through that ghastly operation. I have not the heart to go through with the details. Lucy had got a terrible shock and it told on her more than before, for though plenty of blood went into her veins, her body did not respond to the treatment as well as on the other occasions.
– Bram Stoker
Dracula, Chapter 12. Dr. Seward performs a blood transfusion on the ailing Lucy, but notes that she does not respond as well as on the other occasions. He is remined by Quincey Morris that Lucy has received the blood of "four strong men" in large quantities, but something appears to be taking the blood back out again at night. None of the men, apart from experienced vampire hunter Van Helsing, are aware that Lucy has fallen prey to the blood-sucking Dracula or one of his kind.