In vivisection the animal's eyes are bandaged, so that he does not even
know what is going on, but is free from pain, whilst all the springs of
action, with the one exception, remain in their normal state. This would
not be the case if the animal suffered from acute pain and terror during
the operation. The continued energy of the functions is thought
essential to the complete success of the operation, whether on the human
frame or in vivisection.