I considered Thorndyke's remark for a few moments; and then a light—though not a very brilliant one—seemed to break on me.
"I think I see what you are driving at," said I. "You mean that the change in the writing must be associated with some new condition affecting the writer, and that that condition existed intermittently?"
Thorndyke nodded approvingly, and I continued:
"The only intermittent condition that we know of is the effect of opium. So that we might consider the clearer signatures to have been made when Jeffrey was in his normal state, and the less distinct ones after a bout of opium-smoking."
"That is perfectly sound reasoning," said Thorndyke. "What further conclusion does it lead to?"
"It suggests that the opium habit had been only recently acquired, since the change was noticed only about the time he went to live at New Inn; and, since the change in the writing is at first intermittent and then continuous, we may infer that the opium-smoking was at first occasional and later became a a confirmed habit."
"Quite a reasonable conclusion and very clearly stated," said Thorndyke. "I don't say that I entirely agree with you, or that you have exhausted the information that these signatures offer. But you have started in the right direction."
"I may be on the right road," I said gloomily;
