Dr. McCoy: His brain is gone.
Cptn. Kirk: (mouths silently) His...brain?
Dr. McCoy: It's been removed surgically.
Cptn. Kirk: How could he survive?
Dr. McCoy: It's the greatest technical job I've ever seen. Every nerve ending in the brain must've been neatly sealed. Nothing ripped, nothing torn...no bleeding. It's a medical miracle.
Cptn. Kirk: If his brain is missing, then Spock is dying.
Dr. McCoy: No. That incredible Vulcan physique hung on until the life-support cycle took over. His body lives, the autonomic functions continue. But there is no mind!
— Star Trek: The Original Series, "Spock's Brain"
