Miss Marple and Mystery by Agatha Christie Page A

upon his own subject.
    ‘My dear lady,’ he was saying, ‘what is madness? I can assure you that the more we study the subject, the more difficult we find it to pronounce. We all practise a certain amount of self-deception, and when we carry it so far as to believe we are the Czar of Russia, we are shut up or restrained. But there is a long road before we reach that point. At what particular spot on it shall we erect a post and say, “On this side sanity, on the other madness?” It can’t be done, you know. And I will tell you this, if the man suffering from a delusion happened to hold his tongue about it, in all probability we should never be able to distinguish him from a normal individual. The extraordinary sanity of the insane is a most interesting subject.’
    Sir Alington sipped his wine with appreciation, and beamed upon the company.
    ‘I’ve always heard they are very cunning,’ remarked Mrs Eversleigh. ‘Loonies, I mean.’
    ‘Remarkably so. And suppression of one’s particular delusion has a disastrous effect very often. All suppressions are dangerous, as psychoanalysis has taught us. The man who has a harmless eccentricity, and can indulge it as such, seldom goes over the border line. But the man’ – he paused – ‘or woman who is to all appearance perfectly normal may be in reality a poignant source of danger to the community.’
    His gaze travelled gently down the table to Claire, and then back again. He sipped his wine once more.
    A horrible fear shook Dermot. Was that what he meant? Was that what he was driving at? Impossible, but –
    ‘And all from suppressing oneself,’ sighed Mrs Eversleigh. ‘I quite see that one should be very careful always to – to express one’s personality. The dangers of the other are frightful.’
    ‘My dear Mrs Eversleigh,’ expostulated the physician. ‘You have quite misunderstood me. The cause of the mischief is in the physical matter of the brain – sometimes arising from some outward agency such as a blow; sometimes, alas, congenital.’
    ‘Heredity is so sad,’ sighed the lady vaguely. ‘Consumption and all that.’
    ‘Tuberculosis is not hereditary,’ said Sir Alington drily.
    ‘Isn’t it? I always thought it was. But madness is! How dreadful. What else?’
    ‘Gout,’ said Sir Alington smiling. ‘And colour blindness – the latter is rather interesting. It is transmitted direct to males, but is latent in females. So, while there are many colourblind men, for a woman to be colour-blind, it must have been latent in her mother as well as present in her father – rather an unusual state of things to occur. That is what is called sex-limited heredity.’
    ‘How interesting. But madness is not like that, is it?’
    ‘Madness can be handed down to men or women equally,’ said the physician gravely.
    Claire rose suddenly, pushing back her chair so abruptly that it overturned and fell to the ground. She was very pale and the nervous motions of her fingers were very apparent.
    ‘You – you will not be long, will you?’ she begged. ‘Mrs Thompson will be here in a few minutes now.’
    ‘One glass of port, and I will be with you, for one,’ declared Sir Alington. ‘To see this wonderful Mrs Thompson’s performance is what I have come for, is it not? Ha, ha! Not that I needed any inducement.’ He bowed.
    Claire gave a faint smile of acknowledgment and passed out of the room, her hand on Mrs Eversleigh’s shoulder.
    ‘Afraid I’ve been talking shop,’ remarked the physician as he resumed his seat. ‘Forgive me, my dear fellow.’
    ‘Not at all,’ said Trent perfunctorily.
    He looked strained and worried. For the first time Dermot felt an outsider in the company of his friend. Between these two was a secret that even an old friend might not share. And yet the whole thing was fantastic and incredible. What had he to go upon? Nothing but a couple of glances and a woman’s nervousness.
    They lingered over their wine but a very short