Yet the psychology of deliberate suicide gives us the key to that of the impulsive variety. What in the first case results from conscious, clear, reasoned motives, results in the second from blind, obscure, unconscious states: it is an act of organic life, and its cause is found in cœnæsthesia. Impulsive suicide is the expression of the destructive process, slow, permanent, dimly felt, going on in the depths of the organism. Any one who presses in rage on an aching tooth, who rolls on the ground, strikes his head against the wall, or mutilates himself, is attempting an instinctive though absurd reaction in order to get rid of his pain. These are modified forms, it is true, but they will serve to show that the man who yields to an overmastering impulse to strangle or drown himself seeks a deliverance of the same kind. Leaving degeneration (which is perpetually being dragged into this question) out of account, observation shows us that the difference between the two forms of suicide is reduced to that between psychic and purely organic causes. Impulsive suicide flourishes best on the soil of melancholia and hypochondria—_i.e._, in states which involve deep dejection and a disorganisation of vital action. We may also notice the part played (as was long ago pointed out) by heredity, the descendants of suicidal ancestors often killing themselves at the same age and in the same manner as the latter;[156] now, psychological heredity is based on organic. Finally, the automatic character of these impulses approximates them to the class of reflex actions, attempts at suicide being repeated in the same form during a recurrence of the same circumstances—_e.g._, somnambulism, intoxication, the menstrual period. All these characteristics assign to irresistible suicide an organic origin, which is equivalent to saying that its ultimate cause lies in temperament. The conservative instinct exists in all men, but it may exist in any degree. In some there is an innate joy of life capable of resisting all disasters; in others, a constitutional melancholy, or (which comes to the same thing) _the conservative instinct is very weak_ and yields to the least shock. Impulsive suicide represents self-feeling at its last stage of regression, or, in other words, at its negative extreme. Footnote 156: For further details see my _Hérédité psychologique_, Part I., chap. viii. CHAPTER VI. THE SEXUAL INSTINCT. _Its physiology—Its evolution: Instinctive period—Emotional period (Individual choice)—Intellectual period (Platonic love)—Its pathology—How can sexual instinct deviate from the normal course?—Anatomical and social causes—Psychological causes: (a) unconscious, (b) conscious._ I.