Chapter 2: Search for Mr. Hyde

Lanyon and Jekyll became estranged over a disagreement about scientific experimentation. From this, we can infer that Lanyon wasn't willing to give up his integrity for "unscientific balderdash".

“We had,” was the reply. “But it is more than ten years since Henry Jekyll became too fanciful for me. He began to go wrong, wrong in mind; and though of course I continue to take an interest in him for old sake’s sake, as they say, I see and I have seen devilish little of the man. Such unscientific balderdash,” added the doctor, flushing suddenly purple, “would have estranged Damon and Pythias.”