I learned to smoke, first, cornsilk wrapped in newspaper. I can taste it to this day. We never had the patience to let the cornsilk really dry. What you do is take the cornsilk, spread it out in the sun until it is brown, like the little beard you find in the husk. Wrap it in a spill of newspaper—it'll look more like a very small ice-cream cone than anything else. Set fire to the end, being careful not to torch off your eyebrows. My recollection is that it bore no relationship to tobacco, but it wasn't bad at all. It had one big virtue. When caught, you had not committed a sin, as you did later when you smoked real cigarettes. Real cigarettes stunted your growth, we knew that. What that meant to us was that your growth stopped, right there. You just plain stopped growing, as if you were frozen. You would be three feet tall when you were sixty years old. It was in no way contradictory that we never saw a grownup three feet tall.

Q. At one point in the narrative, the author assumes an instructional tone. Underline two sentences which illustrate this tone.