Besides, I had Yahoo’s Jerry Yang coming to the conference, I had Alibaba’s Jack Ma coming, I had Al Gore coming. I had no time.

That much was very true. Because he was actually a very good doctor, he insisted in an increasingly urgent tone that I go to the hospital right then. That’s because when it comes to strokes, time is critical. You have to get the blood flowing back to the part of the brain that is not getting it.

So I listened, for once, sidelining the obstreperous little sister, and took a car to get an emergency M.R.I.

There it was on the screen: evidence of a transient ischemic attack, often called a mini-stroke. Like the strawberry stain, it was also riveting to look at with its garish neon glow, from the angry yellow clot to the stream of red blood worming its way around it to the multicolored brain of mine full of so many ideas but also just a hunk of misfiring flesh.

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As it turned out, there was a lot of that, including a small hole in my heart through which the clot traveled, as well as me having a type of blood that is more prone to clotting. All of it, combined with not hydrating or walking around enough on the long flight to Hong Kong, created what the doctor, who immediately started the treatment of anticoagulant drugs and others, called a “hole in one.”

That was a good joke at a bad time. It’s funny the things you remember at the critical times of your life. Like the extraordinarily bright whiteness of the surgical mask of that doctor, who also told me that had I not moved faster it would have been so much worse.

“You might have lost your abilities,” he said from somewhere from behind the mask. “You might have died.”