This is from the novella The death of Ivan Ilyich
And suddenly the matter presented itself in a quite different aspect. "Vermiform appendix! Kidney!" he said to himself. "It's not a question of appendix or kidney, but of life and ... death. Yes, life was there and now it is going, going and I cannot stop it. Yes. Why deceive myself? Isn't it obvious to everyone but me that I'm dying, and that it's only a question of weeks, days ... it may happen this moment. There was light and now there is darkness. I was here and now I'm going there! Where?" A chill came over him, his breathing ceased, and he felt only the throbbing of his heart.
... Ivan Ilych saw that he was dying, and he was in continual despair.
In the depth of his heart he knew he was dying, but not only was he not accustomed to the thought, he simply did not and could not grasp it.
The syllogism he had learnt from Kiesewetter's Logic: "Caius is a man, men are mortal, therefore Caius is mortal," had always seemed to him correct as applied to Caius, but certainly not as applied to himself. That Caius — man in the abstract — was mortal, was perfectly correct, but he was not Caius, not an abstract man, but a creature quite, quite separate from all others. ...
"If I had to die like Caius I would have known it was so. An inner voice would have told me so, but there was nothing of the sort in me and I and all my friends felt that our case was quite different from that of Caius. and now here it is!" he said to himself. "It can't be. It's impossible! But here it is. How is this? How is one to understand it?"
He could not understand it, and tried to drive this false, incorrect, morbid thought away and to replace it by other proper and healthy thoughts. But that thought, and not the thought only but the reality itself, seemed to come and confront him. ... He would go to his study, lie down, and again be alone with *It*: face to face with *It*. And nothing could be done with *It* except to look at it and shudder.