In connection with all such neurotic affections we find invariably present a feeling of unrest, hesitation, doubt, conflict, discord, uneasiness, a feeling of anxiety, _conscious or subconscious_, feeling of some impending evil. In all such affections we find the brooding spirit of the most powerful of all animal instincts,--the fear instinct. _Neurosis is a disease of self-preservation and fear._ CHAPTER VII FORMS OF NEUROSIS A brief outline of a classification of nervous and mental diseases, made by me in my various works, may be of help towards a clear understanding of neurotic disturbances. The different forms of nervous and mental diseases may be classified into _Organic_ and _Functional_. By _organic_ affections I mean to indicate pathological modifications of the neuron and its processes taking place in the very structure (probably the cytoreticulum) of the nerve cell. Under this category come such maladies as general paresis, dementia praecox, all mental and nervous affections of a degenerative and involutionary character. Such diseases are termed by me _Organopathies_, or _Necropathies_. By _functional_ affections I mean to indicate all neuron changes in which the functions of the neuron and its reactions to external and internal stimulations are involved in the pathological process without, however, affecting the anatomical structure of the nerve cell. The pathological changes are not permanent,--recovery of normal function is possible with the restitution of favorable conditions of nutrition and elimination. Functional nervous and mental diseases are in turn subdivided into _Neuropathies_ and _Psychopathies_. Neuropathic diseases are disturbances of functioning activity, due to defective neuron matabolism, brought about by external stimuli, and more specially by harmful internal stimuli--glandular secretions, hormones, toxic and autotoxic agencies. The pathological, neuropathic process produces few, if any anatomical, changes in the structure of the neuron. The pathology of neuropathic diseases, (probably of the cytoplasm) is essentially _chemico-physiological_ in nature. Neuropathic diseases include maladies in which the neuron undergoes degenerative changes. At first there is an apparent increase, then an inhibition, and finally a complete suspension of neuron function, not terminating in the destruction of the neuron. Neuron restitution is possible. Such affections are produced by mild poisons, organic, or inorganic, by autotoxic products, by hyposecretion or hypersecretion, or by absence of hormones in the economy of the organism. Here belong all the temporary, or recurrent maniacal, melancholic, delusional states, puerperal mania, epileptic insanity, the mental aberrations of adolescent and climacteric periods, periodic insanity, alternating insanities, and in general all the mental affections known under the description of manic-depressive insanity.