My concussion came after a day of trespassing to take photos in a Bayview-Hunters Point graffiti yard with a college friend. Afterward we went to a bar, where after a single beer and a puff of medical marijuana, I stood up to use the bathroom and awoke to EMTs hovering over me as I lay confused on the floor. They told me I’d passed out cold, and promptly transported me to a hospital by ambulance where I was given a dismissive diagnosis of a mild concussion. “You're in the Tenderloin—we see this all the time,” the attending ER physician told me, before sending me home to be watched by my friend overnight. Other than the bruise to my head, I thought I was okay when I drove home to work the next morning.

Later my general practitioner would order a string of tests—an EEG with forced hyperventilation and strobes to test for epilepsy, a fasting blood-glucose test, and an MRI to look for potential brain and skull injury—all in an attempt to identify why I passed out. He told me my blood tests showed I’m hypoglycemic, and the low blood sugar could have caused me to pass out. But when I asked about my inability to smell, he shrugged off the thing he couldn’t see, the ailment invisible to everyone but me.

The months after the accident were a blur. My first reaction to my loss of smell was curiosity and awe. What a strange thing to suddenly be stripped from one of the antennas I had to the world. Since around 75 percent of the flavor we detect in food comes from the sense of smell, bacon just didn’t do it for me anymore. So I committed to vegetarianism. I stopped wearing perfume, which suddenly seemed a vacuous luxury. But I also began to feel new insecurities about my own scent and the smells in my environment, and I began to dissociate from certain aspects of my life.

My sense of smell was once so keen it would turn me off from certain people and places. In a city, it’s surreal not to smell the putrid decay of garbage bags piled high on the street, not to be romanced by fresh-baked pastries in the wee hours of the morning. Right after the accident, I remember driving to my parents’ house, distraught, crying uncontrollably. I felt cut off from the world around me, trapped inside a body that wasn’t functioning properly. The world seemed flat and dull, as if drained of color. I didn’t want to live without a sense-and-a-half. And, I realized, this loss meant there were suddenly new and unexpected ways my life could end—by gas leak, by fire, or from spoiled food.

Lindsay Comstock

Despite the various ways smell protects us, humans often count it as one of the senses they could do without. (In a recent study by McCann Worldgroup, “53 percent of those aged 16-22 and 48 percent of those aged 23-30 would give up their own sense of smell if it meant they could keep an item of technology.”) For me, too, it was a sense I thought I could do without—until I lost it.