* But not before making another observation startlingly similar to one of my own. Producing a sperm sample, however, was a more delicate matter in seventeenth-century Holland than in twentieth-century New York, so Leeuwenhoek was careful to note that he had obtained his “without sinfully defiling myself” (I confess I had no such compunction myself), rushing his sample to the microscope “before six beats of the pulse had intervened,” leaving his wife no doubt unsatisfied, but giving the world its first valuable clue about the mysterious reproductive process.