Of exciting causes may be enumerated organic or functional diseases of the brain, worry, anxiety, grief, and bodily pain; noise, if not monotonous, fever, coffee, tea, etc. Among the insane, insomnia is one of the most frequent symptoms, except in chronic dementia. In melancholia it is the most distressing accompaniment of the disorder, and is especially marked in the early morning. A careful analysis of the conditions or causes of insomnia has been made by Dr. Folsom (U. S.). The principal ones may be briefly enumerated as follows: Habit, reflex causes, as indigestion, genito-urinary disorders; autotoxic causes, as gout, lithæmia, syphilis, habitual constipation; anæmia, vaso-motor changes, neurasthenia, hallucinations of sight or hearing, astigmatism—the strain of the eye which in health may be unnoticed, producing “in states of debility, headache, dizziness, spasmodic muscular action or wakefulness” and the neurotic temperament.[11] [11] Tuke’s “Dictionary of Psychological Medicine,” vol. i., pp. 703-4. APPENDIX B ABSTRACT FROM ARTICLE: “LUMINOUS SLEEP” By P. ARUNOCHALAM Deep sleep is a sleep of darkness, that is, the sleep of the nerves, and the utter relaxation of the body. Its refreshment is due to absence of thought. Is there a sleep of light, a luminous sleep, in which, while there is absence of thought, there is not darkness and oblivion, but perfect consciousness? To suppose this did not seem irrational to the Greeks. (An instance is cited of the abstracted moods of Socrates, Sympos: 174-5.) (Further citations of this eccentricity of Socrates are in: The Tamil Sage; Charmides; Phaedrus; The Republic; also Tennyson, “The Ancient Sage.”) This reality, sleep that is a sort of abstraction from the bodily condition, is pure consciousness of spirit, “Luminous sleep,” an intellectual and spiritual condition as contrasted with physical sleep. To the general aspects of the genius and life of Ancient Greece, to its philosophy of the reality of pure abstraction, of absolute knowledge and the possibility of attaining it, such a theory would seem reasonable. Dr. Jowett is cited as maintaining that pure abstraction is mere negation. APPENDIX C THESE CLASSICAL, THOUGH ENTIRELY A PRIORI, THEORIES OF SLEEP ARE NOT WITHOUT INTEREST SLEEP AND WAKING By GIOVANNI ARGENTERIO (A.D. 1556) PREFACE