Final answer:
Without additional context or the name of the specific literary work, it is not possible to accurately answer what Mrs. Higgins says about her son and his friend Pickering.
Step-by-step explanation:
The student's question refers to a moment in literature where Mrs. Higgins realizes something about her son and his friend Pickering after finding out about an experiment. However, without the specific context or the name of the literature piece, it is impossible to answer this question accurately. Typically, this kind of inquiry would relate to characters in a play or novel, and their reaction upon discovering the true nature of an experiment or a scheme that has been conducted by other characters.