what was the reason that dr. lanyon became enraged from dr jekyll

In Chapter Two of the novel, 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.