and perfect alibi.  At this point, where the tale is of the exploits of an outside-the-force hero, the police should go off on the wrong trail.  Mysterious letters will serve the writer’s purpose admirably.  The hero, of course, knows better, or at least has better hick, for round about Chapter IV or V, it is customary for the innocent-looking person to make a slip, part of the significance of which strikes the hero in Chapter VI.  The regular police, poor fellows, will not understand it until the end of the novel.
Before we proceed any further we must go back to the details of the murder.  Now, no murder is a murder unless someone is murdered, and no one can be murdered except by something.  The means of the dirty work then arises, and if, as is usual, it seems a simple knife case, then the experienced reader will know that this is much too simple a cause, and thinks of poison.  A doctor at this point should be suspected.  The hero, a brilliant chemist as well as criminologist, should make the discovery in Chapter VII that it is poison, and one or two pages go down very well describing the discomfiture of the police.  South American poisons are very fashionable at the moment (curare is the favourite), for South America is so nice and far away, and, anyhow, most readers by this time are out of their depth.
We have of course assumed generally that it is poison, but it need not be so.  In any case, never take for granted that it is murder by a certain means, if you are told in the first chapter that it is by that means.  By this time, too, the writer should have got to Chapter VIII or so, and the major difficulties are overcome.  The reader is now probably a little confused, and the writer should take advantage of this opportunity to write a chapter in which the detective talks learnedly of blowpipes, poisons, and queer-handled knives.
Then, to add a little variety to the proceedings, there should be introduced a little impersonation, and with the aid of “red herrings,” and elimination, and occasional motor car or boat rides to test alibis, ten chapters or so could be easily added.  Perhaps, too, some shadowing and cigarette ash could be introduced with great effect, and even the most experienced reader is lulled into believing that the murderer is a person Z, when suddenly comes the denouement.  The reader now pulls himself together, and, making two and two equal six, dismisses the obvious person, and finds the outsider as the murderer.
One point about denouements must be made.  It is considered good form by detective story-writers to have a complete group of characters seated round the table while the detective expounds his amazing theory, at fearful danger to himself.  M. Poirot always believes in this method, and two or three pages are well spent in explaining the processes of the little grey cells.  Of course, the murderer may wish to cut up rough, and the police, if not distinguished for brains, can at least play rugby, and the villain is brought down in the approved C. Davey manner.
The story is now almost over, but for some peculiar reason, the writer is always loath to see the murderer appear at the Old Bailey.  Rather it is much more satisfying to reader and writer to see him perform a clever conjuring trick, the outcome of which is the disappearance of cyanide, and the sudden end of yet another character in the tale.  Little remains but for the hero to hand over the praise to the police, and for a few further remarks on humanity and little grey cells.
This article is not intended to criticise the great detective writers of the day.  All the more praise to their art, when from scanty materials they produce such wonderfully polished creations, and no better evening can be spent than in the company of Dorothy L. Sayers, Agatha Christie, or Freeman Wills Crofts.
R. D. James (U.C.W, Aber.)