One morning, leaving for work, I stepped outside the gate of my apartment building and heard a rustle of activity to my left. I turned to see a tiny dog trotting toward me on the sidewalk, looking nervously back at a knot of people who were following and calling out.

An escapee, I thought, as the dog, a Chihuahua, reached me, jumped up on my legs and looked at me beseechingly. Without thinking, I bent down, picked her up and held her out to her followers.

Their hands flapped in the air as they all murmured in a disjointed chorus, “No, no, someone just threw her out of a car window, we wanted to get her out of the busy road, good luck,” their voices trailing off as they about-faced and disappeared down the block.

I looked down. The little dog was trembling in my arms. I sighed and took her inside, where my sweet, faithful old mutt had already settled in for his morning nap. He too sighed, watching her from his bed as she fluttered about the apartment, tapping out an anxious rhythm on the wood floors.

I was in my early 30s and an oncology fellow at the University of Chicago. Medicine had called me with a message of job security and financial stability, not human connection and healing. While I was growing up, vocations always seemed to me a luxury.

“Never depend on anyone for money,” my grandmother often said, apropos of nothing.

Like many doctors, I thought my primary duty was to counter uncertainty with facts. The field of oncology was, and still is, breathtakingly prolific at generating new facts, and I had a growing sense of mastery over doubt and disease.