It may also be stated, in general terms, that the emotions are manifested in inverse ratio to the subject's mental or volitional power. {20} Psychologically, the emotions are intimately related, on the one hand, with sensory functions, and on the other with more purely mental functions. Anatomically, it is probable that emotions are generated in basal ganglia of the brain (thalami optici and ganglion pontis), in close association with the sensory areas of the cortex cerebri, while the volitional, inhibitory power is derived from regions of the cortex situated frontad. Clinically, we meet with abnormal emotional states in a great many diseases of the nervous system, more especially in hysteria, neurasthenia, and insanity. DEPRESSION in the psychic sphere manifests itself by the presence of psychic pain (psychalgia), by slowness of emotive reaction and of intellection, and by the predominance of fear, grief, and other negative emotional states. This complex mental state is usually accompanied by corresponding physical symptoms—general debility, reduced muscular strength, slowness of visceral functions, and retarded metamorphosis. The features are relaxed and passive; the posture sluggish, indifferent, or cataleptoid; the animal appetites are reduced. It is seldom that the entire economy does not sympathize with the psychic state. In exceptional cases some emotions are abnormally active, as in hypochondriasis; or there may be abnormally active muscular movements, as in melancholia agitata. Usually, depression is a part (a fundamental part, however) of a more complex symptom group, as in hypochondriasis, melancholia, hysteria, the prodromal stage of mania or paralytic dementia, etc.; but sometimes it constitutes a so-called disease—melancholia sine delirio. Although depressed subjects often appear indifferent to their surroundings, and react slowly or not at all, it must not be supposed that their emotions are not subjectively active. They are often abnormally so, and psychic hyperæsthesia coexists with psychalgia. No anatomical seat can be assigned to the processes which constitute this state and the following; their psychic mechanism is unknown.