To answer this question, you will need to return to Chapter Three of this incredible classic, which details our and Victor's first introduction to Waldman and the impact that his teaching had on the young and impressionable Victor Frankenstein. To try and identify the literary devices that are used to explore the seismic consequences his teaching had, consider the following description from Victor about Waldman's opening to his lecture:
Such were the professor's words--rather let me say such the words of fate, enounced to destroy me. As he went on, I felt as if my soul were grappling with a palpable enemy; one by one the various keys were touched which formed the mechanism of my being: chord after chord was sounded, and soon my mind was filled with one thought, one conception, one purpose.
Note the simile that is used to compare the impact of Waldman's lecture to a conflict between Victor's soul and some "palpable enemy." Clearly Waldman's lecture can be compared to lighting some kind of fuse in Victor's inner being, as he feels a tremendous conflict and also he also feels that his fate is being decided. Thus a simile is used to describe the impact of Waldman's lecture on Frankenstein.