[42] It should not be forgotten that when a patient in an early stage of mental disorder voluntarily seeks the doctor, his _active co-operation_ in the task of tracing the causal factors of his trouble is of the greatest value. This assistance cannot be relied upon after the patient has been certified as insane and removed to an asylum, or even after he has been taken to the doctor at the instance of others. For obvious reasons he is then more likely to hide than to reveal his eccentricities. The simulation of insanity is comparatively rare: it is difficult and usually easily detected. It is dissimulation—the concealment of symptoms of disease—which is the doctor’s greatest enemy. The deluded man may hide his delusions because “everyone knows that these beliefs are mad:” the melancholic may pretend for the time to be cheerful in order that his liberty may not be interfered with. (_Cf._ K. Jasper’s _Allgemeine Psychopathologie_, Berlin, 1913, p. 317.) Such attitudes of the patient are obviously strengthened by our present custom of delaying the treatment of mental disorder. [43] In his account of the wonderful exploits of “Sherlock Holmes,” Sir Arthur Conan Doyle was merely applying, with inimitable skill and literary resourcefulness, the methods of clinical diagnosis in medicine to the detection of imaginary crimes. The unusual phenomenon in medicine or in crime often affords the most obvious clue to the expert who can appreciate its significance, whereas a simple dyspepsia or a commonplace murder may present insoluble problems, because they reveal no distinctive signs to guide the investigator. [44] p. 17_f._ [45] Dr. C. G. Jung’s view, _Analytic Psychology_, p. 234. [46] It is of importance to remember that successful re-education utilises the emotional factors in the patient’s mental make-up, by helping him to realise the value of the things which will make life once more attractive and worth living. In this process the more the physician knows of the patient’s social, moral or religious relations, the earlier and more satisfactory will be his success. [47] CORRECTION. An unfortunate error in the second paragraph on page 73 escaped our notice during the correction of proofs. Professor Pierre Janet was not formerly the teacher of Professor Freud, but his fellow pupil when they were studying under Charcot in Paris. [48] _Op. cit._, p. 256_f._ [49] _Cf._ Hart, _op. cit._, p. 69_f._, Jung, _op. cit._ CHAPTER IV. Some General Considerations. It is instructive to compare the public attitude towards insanity with that adopted in the case of another serious disease, tuberculosis.