The experience of a medical and scientific education is transformational. It is like moving to a new country. At first, you don’t know the language, let alone the customs and concepts. But then, almost imperceptibly, that changes. Half the words you now routinely use you did not know existed when you started: words like arterial-blood gas, nasogastric tube, microarray, logistic regression, NMDA receptor, velluvial matrix. O.K., I made that last one up. But the velluvial matrix sounds like something you should know about, doesn’t it? And that’s the problem. I will let you in on a little secret. You never stop wondering if there is a velluvial matrix you should know about.