The opening paragraph of neurosurgeon Henry Marsh’s excellent Granta essay about what goes on in his brain as he is slicing open someone else’s:

“I often have to cut into the brain and it is something I hate doing. With a pair of short-wave diathermy forceps I coagulate a few millimetres of the brain’s surface, turning the living, glittering pia arachnoid – the transparent membrane that covers the brain – along with its minute and elegant blood vessels, into an ugly scab. With a pair of microscopic scissors I then cut the blood vessels and dig downwards with a fine sucker. I look down the operating microscope, feeling my way through the soft white substance of the brain, trying to find the tumour. The idea that I am cutting and pushing through thought itself, that memories, dreams and reflections should have the consistency of soft white jelly, is simply too strange to understand and all I can see in front of me is matter. Nevertheless, I know that if I stray into the wrong area, into what neurosurgeons call eloquent brain, I will be faced with a damaged and disabled patient afterwards. The brain does not come with helpful labels saying ‘Cut here’ or ‘Don’t cut there’. Eloquent brain looks no different from any other area of the brain, so when I go round to the Recovery Ward after the operation to see what I have achieved, I am always anxious.” (Thanks Browser.)