Hematuria is always an alarming symptom and its cause must be carefully sought by the conscientious physician. If there are repeated short spells of bleeding a malignant lesion somewhere in the urinary tract should be suspected. When the bleeding is associated with dysuria and occurs in the earlier part of life, a tuberculous infection would be a more probable cause; if bleeding is accompanied by severe colic, the presence of calculus is suggested. When hematuria is painless and of long duration, disappearing for weeks at a time, the possibility that it is of the so-called idiopathic or essential type must be considered. In order to make this diagnosis, cystoscopic examination is necessary, at which, all other causes of bleeding being excluded, a diagnosis of essential hematuria is reached by the process of elimination. Some urologists are of the opinion that such a diagnosis serves as a cloak for ignorance of