Final answer:
Victor Frankenstein decides to study medicine after creating the monster, shifting from the broader field of natural philosophy.
Step-by-step explanation:
After the creation of the monster, Victor Frankenstein decides to give up natural philosophy and instead studies medicine. Natural philosophy, during Victor's time, was a broad field that encompassed many areas of science, including biology, chemistry, and physics, but after his harrowing experience, Victor turns towards the study of medicine, which is closely related to the knowledge that facilitated the creation of his monster. This choice reflects his desire to understand and possibly correct the consequences of his earlier scientific exploits.