how has dr lanyon opion of dr jekyll semmed to recently shirft and what clues does stevenson offer about why this might be the case

In Chapter Two, Utterson goes to visit Dr. Lanyon, another dear friend of Dr. Jekyll's. When the men begin talking about Jekyll, Utterson discovers that Lanyon has not spoken to Jekyll for a long period of time due to a disagreement over "unscientific balderdash." Utterson also learns that Lanyon has never heard of Hyde. This interaction alerts the reader to the fact that Lanyon disapproves of Jekyll's work.