1. Humboldt smiled, took a louse from the mistress´s hair and put that under the instrument.
    洪堡笑了笑，从那位贵妇的头上也拿下了一只虱子放到了显微镜的下面。

2. On one occasion Humboldt took a louse from a servant´s hair and put it under the microscope.
    一次，洪堡从一个仆人的头上拿下一只虱子放到了显微镜的下面。