What happens when Victor sees an oak tree destroyed by lightning and hears an explanation? What does Victor then begin to study?

When Victor sees an oak tree destroyed by lightning in chapter 2, a family friend happens to be visiting. This man is knowledgeable about what we would call cutting-edge science, although Victor calls it "natural philosophy." The man astonishes Victor with a theory he has about how electricity can be used to "galvanize," or shock, something into life. This information makes Victor throw aside the men whose work he had been studying, such as Cornelius Agrippa, Albertus Magnus, and Paracelsus, and think that "nothing would or could ever be known."
This is the opposite of what we would expect from a boy who has been so interested in science and alchemy, but Victor drops these studies completely. He decides that natural history is "a deformed and abortive creation" that can never yield any true knowledge.
Instead, he turns his mind and his studies to a field that seems much more sold to him: mathematics. He considers his change in interest "miraculous" and the last effort of a "guardian angel" to save him from his fate.