But while the contributions of anatomy, physiology and pathology to the treatment of psychoneuroses have not yet gone beyond theoretical and mutually conflicting suggestions, the psychological method of investigation and treatment on the other hand has proved itself of practical use in restoring patients to a normal state of mental health. What scientific justification therefore have we, when considering the action of heredity, for lumping together the organic and the functional mental disorders? The psychoneurosis is often simply a progressive state of mal-adaptation to environment; a mental twist which can be corrected if treated suitably at a sufficiently early stage. Its specific nature is frequently explicable almost entirely in terms of the peculiar educational, family or social relations of the patient’s environment. The war has shown us one indisputable fact, that a psychoneurosis may be produced in almost anyone if only his environment be made “difficult” enough for him.[59] It has warned us that the pessimistic, helpless appeal to heredity, so common in the case of insanity, must go the same way as its lugubrious homologue which formerly did duty in the case of tuberculosis. In the causation of the psychoneuroses, heredity undoubtedly counts, but social and material environment count infinitely more. To some readers the above argument may seem so obvious as to be superfluous. To ascribe a patient’s entangled state of mind to heredity without attempting to discover how far his own personal experiences have tended to bring about that mental condition, would seem as fatuous as attributing to heredity the financial muddles of a son who has inherited from his unbusinesslike father a badly managed estate. The trade-adviser called in to help might for a moment consider the possibility that the son may have inherited his father’s unpractical character, but surely his first serious efforts would be to discover where the business methods were wrong or antiquated and to improve on them. So it is with the mental patient; his own history is the important desideratum. That of his parents may cast valuable light upon his trouble, but even then it is often just because their own difficulties have contributed to the making of his environment.