The SYMPTOMS produced by either sarcoma or carcinoma may be none at all for a time. Dull pains in the loins or referred to the hypochondrium--which, however, from their indefiniteness can have but little diagnostic importance--are among the early phenomena. Pains like nephritic colic may appear. The urine usually shows little of importance. There may be sympathetic disturbance of micturition, but unless hemorrhage occurs there is not likely to be anything in the urine discoverable by the microscope to fix the nature of the trouble. Fragments of cancer-structure in the very rare cases in which they are said to have been found would of course be conclusive, but evidence based on the alleged discovery of cancer-cells in the urine must be received with the utmost caution, recollecting the great variety of shapes and sizes assumed by the epithelium of the urinary passages. Hæmaturia is a symptom occurring in only a portion of the cases, its appearance in a given case evidently depending on the way in which the tumor invades the kidney and increases in size. If growing in such a way as to compress the ureter at an early stage before any erosion of the mucous membrane has taken place, blood, even if set free in the pelvis, cannot reach the bladder. If hæmaturia is present before any tumor can be felt, it has {62} only a subordinate value, but if occurring after the discovery of such a tumor, the combination is of the highest significance. At a later period all the symptoms of compression of other abdominal viscera arise--anorexia, vomiting, jaundice, oedema, ascites, emaciation, and death. When a tumor has become evident, it is to be diagnosticated from cystic disease and from hydro-nephrosis, with which it agrees in position and possibly in form. From the former of these its hardness and rapid growth, the invasion of other organs, and the cachexia will serve to distinguish it. Hæmaturia is not present in cystic disease. From hydro-nephrosis or pyo-nephrosis the diagnosis has already been stated. On the right side it might not in every case be easy to distinguish a morbid growth of the kidney from one affecting the liver, and a similar difficulty might arise on the other side with the spleen. The diagnosis is to be made by a careful location of the tumor by palpation and percussion and the absence of symptoms likely to occur in connection with affections of the organs named. In children psoas abscess and degeneration of the lumbar lymphatic glands should also be considered. A sarcoma of the kidney has been mistaken and punctured for an empyema. A sarcoma behind the kidney, pushing it forward, is very difficult to distinguish from a similar growth affecting the organ itself, especially as it is likely to give rise to signs of renal irritation discoverable by the microscope. A slight pyelitis, distinguished by pus and the absence of any cellular elements to indicate an origin at a lower point, has been observed in such a case.