The fundamental features of passive depression are lassitude, discouragement, resignation. It is always associated with a marked degree of psychic inhibition, aboulia, and moral anaesthesia, and may be complicated by delusions and hallucinations. It is accompanied by organic changes which have been extensively studied by physiologists (Darwin, Claude Bernard, Lange), and to which Dumas has devoted one of the most interesting chapters in his book, "La tristesse et la joie."

Depression is always associated with a state of peripheral and probably cerebral vaso-constriction, in which Lange believed he had found the immediate cause of this emotion. This vaso-constriction is apparent in the pallor of the skin, coldness of the extremities, and absence of the peripheral pulse, which are constant features of the depression of melancholia. The opinion of Lange is, however, too exclusive. "This vaso-constriction, which in the peripheral organs results in coldness and pallor of the tissues, brings about in the brain a condition of anaemia, undoubtedly contributing to the maintenance of the mental and motor inertia; but it cannot be asserted positively that it is the only cause of these phenomena. Morselli and Bordoni-Uffreduzzi have shown long since, in fact, that the phenomena of depressed intellectual activity may appear before the cerebral circulatory changes; this leads to the conclusion that depression begins with being the cause of the circulatory changes before becoming subject to their influence." l

1 La tristesse et la joie, p. 29. Paris, F. Alcan.

In the very rare cases in which, in spite of the peripheral vaso-constriction, the cardiac impulse retains its force, the blood pressure, according to the laws formulated by Marey, rises; this condition constitutes the first type of depression, depression with hypertension.

But almost always the heart participates in the general atony characterizing depression, so that the blood pressure falls in spite of the peripheral vaso-constriction: this constitutes the second type of depression, depression with hypotension (Dumas).

The respiratory disorders are no less constant than the circulatory ones. The respirations are shallow, irregular, interrupted by deep sighing. The quantity of carbon dioxide excreted tends to diminish.

The general nutrition is impaired; this results in loss of flesh, which is but slight if the depression lasts no longer than a few days, and which persists as long as the affective phenomenon itself. The weight does not return to the normal until the depression disappears, i.e., until the patient either recovers or becomes demented.

The appetite is diminished, the tongue is coated, the breath is offensive. The process of digestion is accompanied by discomfort and often by pain in the epigastrium. Finally, there is almost always constipation.

The sluggish metabolism shown by the diminished elimination of carbon dioxide is also apparent from the quantitative and qualitative changes in the urinary excretion. The quantity of urine voided in twenty-four hours is diminished. The quantity of urea, as well as that of phosphoric acid, is also diminished. (Observations of Dumas and Serveaux.)

1 Dumas. Loc. cit., p. 239.

The toxicity of the urine in depression is undoubtedly of interest, but the results so far obtained are somewhat conflicting. According to some authors it is increased, according to others, diminished. This subject, still in a state of confusion, should be excluded from the domain of practical psychiatry.