Walking out my front door, I catch a whiff of a sweet fragrance. The smell, courtesy of my blooming hackberry tree, is distinctive, a little heavier than the perfume that seems to envelope the area around the gardenia plant in my courtyard. And both are decidely different from the delicate odor offered by my blooming jasmine.

I rarely stop to think about the integral part that smell plays in a life; in fact, my olfactory abilities probably are the least developed of my senses. And yet, the sense...