All that stirring of old instincts which at stated periods drives men out from the sounding cities to forest and plain to kill things by chemically propelled leaden pellets, the blood lust, the joy to

All that stirring of old instincts which at stated periods drives men out from the sounding cities to forest and plain to kill things by chemically propelled leaden pellets, the blood lust, the joy to kill—all this was Buck's, only it was infinitely more intimate.

The words "chemically propelled leaden pellets" are describing _____.

stones

harnesses

bullets

arrows