In a post-Hiroshima world, Dr. Dell resigns from a weapons lab to farm, and when Dr. Curtis Johnson visits to persuade him to come back, he finds that Dell’s reasons are linked to time travel.
Here within this brain of mine has been conceived a thing which will probably destroy a billion human lives in the coming years. D. triconus toxin in a suitable aerosol requires only a countable number of molecules in the lungs of a man to kill him. My brain and mine alone is responsible for that vicious, murderous discovery.

Variants

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  1. “A Stone and a Spear” by Raymond F. Jones, in Galaxy, December 1950.
    2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . written by Raymond F. Jones