There is one thing that is fairly certain, an artist can only develop on the lines which nature has marked out for him, his mode of expression is of the essence of his personality and the attempt to assume a new one is futile.

But an artist has the right to be judged by his best work. This he generally produces within a comparatively few years.

Part of the First World War I spent in a sanatorium for the tuberculous in the North of Scotland and there I learnt how pleasant it is to lie in bed, what a delicious sense of liberation it affords from the responsibilities of life and how conducive it is to profitable reflection and aimless reverie. Since then whenever I can square it with my conscience I go to bed.

The theory of the detective story is simple. Someone is murdered, there is an investigation, the culprit is discovered and pays the penalty of his crime. This is the classic formula and it contains in itself all the elements of a good story, for it has a beginning, a middle and an end.

I sometimes wonder idly about their writers. Are they seized with a divine afflatus and do they write because they must with the anguish of spirit with which Flaubert wrote Madame Bovary? I refuse to believe that they sit down deliberately to write, tongue in cheek, something that will bring them in a tidy sum of money. If they did I would not blame them, for evidently this is a pleasanter way of earning a living than by selling matches in the street, which exposes you to the inclemency of the weather, or being an attendant in a public lavoratory, which affords but a narrow view of human nature.

Sympathy is a very ticklish thing. It often attaches itself to a character contrary to the author's intention.

It is hard to believe now, as the Victorians did, in unrelieved villainy. We know that people are a mixture of good and bad; we do not believe in them when they are represented as all good or all bad, and as soon as we no longer do that, the author has lost us. We do not care what happens to his puppets.

The fact remains that Sherlock Holmes caught and has held the public fancy. His name is a household word in every country in the civilised world. He was drawn in broad and telling lines, a melodramatic figure, with marked idiosyncrasies which Conan Doyle hammered into the minds of his readers with the same pertinacity as the great advertisers use to proclaim the merits of their soap, beer or cigarettes, and the results were as remunerative. You know no more of Sherlock Holmes after you have read fifty stories than you did after reading one, but the constant reiteration has broken down your resistance.

Of course it is galling to the writers of these clever books, which are read by everybody, high-brows, middle-brows and low-brows, that they should bring them so little credit. Are they invited to luncheon parties in Chelsea, or in Bloomsbury, or even in Mayfair?

We will have to account for the enormous popularity of this particular variety of fiction. My explanation is simple. The detective writers have a story to tell and they tell it briefly. They must capture and hold the reader's attention and so must get into their story with dispatch. They must arouse curiosity, excite suspense and by the invention of incident maintain the reader's interest. They must enlist his sympathy for the right characters. Finally they must work up to a satisfactory climax. They must in short follow the natural rules of storytelling that have been followed ever since some nimble-witted fellow told the story of Joseph in the tents of Israel.

Now, the 'serious' novelists of today have often little or no story to tell; indeed they have allowed themselves to be persuaded that to tell a story is a negligible element in the art they practise. And they have only themselves to blame if the writers of detective stories have stolen their readers from them.

Fiction is an art, but an imperfect one. The great novels of the world may deal with all the passions to which man is subject, discover the depths of his variable and disconsolate soul, analyse human relations, describe a civilisation or create immortal characters; it is only by a misuse of the word that beauty can be ascribed to them. We writers of fiction must leave beauty to the poets.

It would be foolish to suppose that our opinions are any more definitive than those of our fathers, and we may be pretty sure that our descendants will look upon them with the same perplexity.

Is the farmer conscious of the beauty of the landscape in the sight of which he earns his daily bread? I should say not; he is concerned to plough a field or to dig a ditch. The appreciation of the beauty of nature is a recent acquisition of the human race. It needs leisure and sophistication.

It may be that beauty, like happiness and originality, is more likely to be obtained when it is not deliberately attempted.

No one can have lived much in the society of those whom Kant calls connoisseurs of taste, and whom we may more conveniently call aesthetes, without noticing how seldom it is that you find in them the modesty, the tolerance, the loving-kindness and liberality, in short the goodness with which you might have expected their addiction to spiritual pleasures to inform them.

It is with just such sardonic and unscrupulous humour that posterity orders literary fame. Its wilfulness is beyond reason. It takes no account of virtue and little of industry; it is indifferent to high endeavour and sincerity of purpose.

The characters' motives were, as in so much of Henry James's work, not the motives of normal human beings, and though in his fiction he was persuasive enough very often to conceal the fact from the reader, presented on the stage they glaringly lacked plausibility. Why he failed as a dramatist is obvious enough. He was like a man who because he can ride a bicycle thinks he can ride a horse.