human hair, a complete palette, so to speak, of samples gathered in every quarter of the globe.  Henceforth burglars, who already wear gloves or paint their fingers with a rubber composition for fear of leaving finger-prints, will have to wear close-fitting caps or keep their heads shaved.  Thus he has hit upon a new method of identification of those sought by the police.  For instance, from time to time the question arises whether hair is human or animal.  In such cases the microscope tells the answer truthfully.

“For a long time I have been studying hair, taking advantage of those excellent researches by M. Bertillon.  Human hair is fairly uniform, tapering gradually.  Under the microscope it is practically always possible to distinguish human hair from animal.  I shall not go into the distinctions, but I may add that it is also possible to determine very quickly the difference between all hair, human or animal, and cotton with its corkscrew-like twists, linen with its jointed structure, and silk, which is long, smooth, and cylindrical.”

Again Kennedy paused as if to emphasise this preface.  “I have here,” he continued, “a sample of hair.”  He had picked up a microscope slide that was lying on the table.  It certainly did not look very thrilling—­a mere piece of glass, that was all.  But on the glass was what appeared to be merely a faint line.  “This slide,” he said, holding it up, “has what must prove an unescapable clue to the identity of the man responsible for the disappearance of Miss Gilbert.  I shall not tell you yet who he is, for the simple reason that, though I could make a shrewd guess, I do not yet know what the verdict of science is, and in science we do not guess where we can prove.

“You will undoubtedly remember that when Miss Gilbert’s body was discovered, it bore no evidence of suicide, but on the contrary the marks of violence.  Her fists were clenched, as if she had struggled with all her power against a force that had been too much for her.  I examined her hands, expecting to find some evidence of a weapon she had used to defend herself.  Instead, I found what was more valuable.  Here on this slide are several hairs that I found tightly grasped in her rigid hands.”

I could not help recalling Kennedy’s remark earlier in the case—­ that it hung on slender threads.  Yet how strong might not those threads prove!

“There was also in her pocketbook a newspaper clipping bearing the advertisements of several clairvoyants,” he went on.  “Mr. Jameson and myself had already discovered what the police had failed to find, that on the morning of the day on which she disappeared Miss Gilbert had made three distinct efforts, probably, to secure books on clairvoyance.  Accordingly, Mr. Jameson and myself have visited several of the fortune-tellers and practitioners of the occult sciences in which we had reason to believe Miss Gilbert was interested.  They all, by the way, make a specialty