Dr. Lanyon is an intelligent, respectable lawyer who is suspicious the "Mr. Hyde" is threatening or bullying Dr. Jekyll into giving him property and leaving money for him in his will. Because Dr. Lanyon is an intelligent man, he always looks for a logical, practical answer, which is why he does not wonder is Hyde and Jekyll are the same person.
Answer:
I won't write 100 words for the answer but the theme is the process of becoming.
I think: ecology, inheritance and zoology
