an old hand.  My object was to gain time.  I wanted the body to be fairly cold and stiff before being discovered, though there was not much danger here; for, as you saw by the medical evidence, there is no telling the time of death to an hour or two.  The frank way in which I said the death was very recent disarmed all suspicion, and even Dr. Robinson was unconsciously worked upon, in adjudging the time of death, by the knowledge (query here, Mr. Templeton) that it had preceded my advent on the scene.

“Before leaving Mrs. Drabdump, there is just one point I should like to say a word about.  You have listened so patiently, sir, to my lectures on the science of sciences that you will not refuse to hear the last.  A good deal of importance has been attached to Mrs. Drabdump’s oversleeping herself by half an hour.  It happens that this (like the innocent fog which has also been made responsible for much) is a purely accidental and irrelevant circumstance.  In all works on inductive logic it is thoroughly recognised that only some of the circumstances of a phenomenon are of its essence and casually interconnected; there is always a certain proportion of heterogeneous accompaniments which have no intimate relation whatever with the phenomenon.  Yet, so crude is as yet the comprehension of the science of evidence, that every feature of the phenomenon under investigation is made equally important, and sought to be linked with the chain of evidence.  To attempt to explain everything is always the mark of the tyro.  The fog and Mrs. Drabdump’s oversleeping herself were mere accidents.  There are always these irrelevant accompaniments, and the true scientist allows for this element of (so to speak) chemically unrelated detail.  Even I never counted on the unfortunate series of accidental phenomena which have led to Mortlake’s implication in a network of suspicion.  On the other hand, the fact that my servant, Jane, who usually goes about ten, left a few minutes earlier on the night of December 3rd, so that she didn’t know of Constant’s visit, was a relevant accident.  In fact, just as the art of the artist or the editor consists largely in knowing what to leave out, so does the art of the scientific detector of crime consist in knowing what details to ignore.  In short, to explain everything is to explain too much.  And too much is worse than too little.

“To return to my experiment.  My success exceeded my wildest dreams.  None had an inkling of the truth.  The insolubility of the Big Bow Mystery teased the acutest minds in Europe and the civilised world.  That a man could have been murdered in a thoroughly inaccessible room savoured of the ages of magic.  The redoubtable Wimp, who had been blazoned as my successor, fell back on the theory of suicide.  The mystery would have slept till my death, but—­I fear—­for my own ingenuity.  I tried to stand outside myself, and to look at the crime with the eyes of another, or of my old self.  I found the work of art so perfect