“The late Arthur Constant,” continued the great criminologist, “came to live nearly opposite me.  I cultivated his acquaintance—­he was a lovable young fellow, an excellent subject for experiment.  I do not know when I have ever taken to a man more.  From the moment I first set eyes on him, there was a peculiar sympathy between us.  We were drawn to each other.  I felt instinctively he would be the man.  I loved to hear him speak enthusiastically of the Brotherhood of Man—­I, who knew the brotherhood of man was to the ape, the serpent, and the tiger—­and he seemed to find a pleasure in stealing a moment’s chat with me from his engrossing self-appointed duties.  It is a pity humanity should have been robbed of so valuable a life.  But it had to be.  At a quarter to ten on the night of December 3rd he came to me.  Naturally I said nothing about this visit at the inquest or the trial.  His object was to consult me mysteriously about some girl.  He said he had privately lent her money—­which she was to repay at her convenience.  What the money was for he did not know, except that it was somehow connected with an act of abnegation in which he had vaguely encouraged her.  The girl had since disappeared, and he was in distress about her.  He would not tell me who it was—­of course now, sir, you know as well as I it was Jessie Dymond—­but asked for advice as to how to set about finding her.  He mentioned that Mortlake was leaving for Devonport by the first train on the next day.  Of old I should have connected these two facts and sought the thread; now, as he spoke, all my thoughts were dyed red.  He was suffering perceptibly from toothache, and in answer to my sympathetic inquiries told me it had been allowing him very little sleep.  Everything combined to invite the trial of one of my favourite theories.  I spoke to him in a fatherly way, and when I had tendered some vague advice about the girl, I made him promise to secure a night’s rest (before he faced the arduous tram-men’s meeting in the morning) by taking a sleeping draught.  I gave him a quantity of sulfonal in a phial.  It is a new drug, which produces protracted sleep without disturbing digestion, and which I use myself.  He promised faithfully to take the draught; and I also exhorted him earnestly to bolt and bar and lock himself in so as to stop up every chink or aperture by which the cold air of the winter’s night might creep into the room.  I remonstrated with him on the careless manner he treated his body, and he laughed in his good-humoured, gentle way, and promised to obey me in all things.  And he did.  That Mrs. Drabdump, failing to rouse him, would cry ‘Murder!’ I took for certain.  She is built that way.  As even Sir Charles Brown-Harland remarked, she habitually takes her prepossessions for facts, her inferences for observations.  She forecasts the future in grey.  Most women of Mrs. Drabdump’s class would have behaved as she did.  She happened to be a peculiarly favourable specimen for working on