As previously stated, ventricular fibrillation is a very serious condition, and may be a cause of sudden death in angina pectoris, and is probably then caused by disturbed circulation in one of the coronary arteries causing an irregular blood supply to one or other of the ventricles. Absorption of some toxins or poisons which could act on the blood supply of the ventricles could also be a cause of this condition. This irregular ventricular contraction sometimes displaces the apex beat. PATHOLOGY Schoenberg [Footnote: Schoenberg: Frankfurt. Ztschr. f. Pathol., 1909, ii, 4.] finds that in auricular fibrillation there are definite signs in the node, such as round cell infiltration, showing inflammation, a fibrosis of the tissue, and perhaps a sclerosis of the blood vessels of that region. He also found that compression of this nodal region of the auricle from some growth or other disturbance in the mediastinal region could cause auricular fibrillation. Jarisch [Footnote: Jarisch: Deutsch. Arch. f. klin. Med., 1914, cxv, 376.] finds by personal investigations and by studying the literature that the node showed pathologic disturbance in less than half the cases. Consequently, although a pathologic condition of the node is a frequent, and perhaps the most frequent, cause of auricular fibrillation, other conditions, especially anything which dilates the right auricle, may cause it. DIAGNOSIS If the pulse is intermittent and there is apparently a heart block. Stokes-Adams disease should be considered as possibly present, and digitalis would be contraindicated and would do harm.