I am indebted to Mr. F. T. Paul, of Liverpool, for revising for the purposes of this work, so far as renal tumors are concerned, the classi fication which was originally drawn up by him as an introduction to a discussion on the new growths of the bladder, prostate, and kidney." The investigation on which this is based was undertaken at the re quest of the British Medical Association by a committee consisting of Mr. Paul, Mr. Rushton Parker, Dr. Alexander, and myself.
From the foregoing classification it will be seen that tumors of the kidney may for clinical purposes be considered as of two kinds, namely, innocent and malignant. The broad distinctions between these two classes are those which are recognized as being applicable to growths generally wherever they may occur in the human body. It will be well, in the first place, to ascertain the circumstances which would lead us to believe that a kidney is the subject of a growth or enlargement bringing it under either of these two denominations, and the features which, when present, enable us to differentiate between varieties of these formations.
It is generally admitted that among abdominal enlargements and tumors those taking their origin in the kidney are probably the most difficult to diagnose. They are not unfrequently associated with ascites, and when this complication exists the task of drawing distinc tions, especially in stout persons, is by no means an easy one. The encroachments proceeding from other organs such as the liver, spleen, suprarenal capsules and the growths connected with them, for in stance hydatids, present other sources of embarrassment. Further, we have to take into consideration the possibility of a renal growth being initiated by one of those tumors taking their origin in the cap sule of the kidney or in the connective tissue surrounding it, which have more recently been described by Dr. Vander Veer under the title of " Retro-Peritoneal Tumors." Then there are abnormalities in the position and relations of the abdominal viscera of not unfrequerit occurrence which have added in no small measure to the difficulties connected with making a diagnosis. In these ways sources of doubt in some cases may easily arise, rendering it almost impossible to arrive at a conclusion without the assistance of some kind of explor atory operation. In coming to a diagnosis, or at all events in en
deavoring to do so, it is best in most cases to proceed step by step by what is well recopiized in surgery as the process of exclusion. In these investigations we shall do well, where it is necessary, to avail ourselves of the assistance that is often rendered by the aspirator and exploring needle, by a careful quantitative, qualitative, and micro scopical examination of the urine, iu addition to the ordinary modes of manipulative examination. In some cases the cystoscope, in de termining the action of the respective ureters as well as the nature of the fluids they emit, will prove of service. Again, instances will occur where in defining the nature and limits of a tumor in the kidney such a complete relaxation of the abdominal parietes will be required as can only be secured by the administration of an anesthetic. In the female an examination of the pelvic contents by the vagina may be called for, for instance in the differential diagnosis between an ovarian tumor and an enormous fluid dilatation of the kidney, as re ferred to in connection with the subject of hydronephrosis. In a male child, in a doubtful kidney case, I remember an instance where the detection, by the finger in the rectum, of a stone impacted in the lower end of the ureter proved of material importance. Then, again, the freces should not be allowed to go without inspection; the absence or presence of bile in them may throw some light on an ob scure case. Writing in reference to the diagnosis of retro-peritoneal tumors Dr. Vander Veer remarks as being of service "the rectal in suffiation of hydrogen gas, with the distention of the stomach; more especially where a careful examination has been made before and the percussion areas have been outlined upon the abdomen. The pro cess of insufflation should be watched, that the relation of the intes tinal tube to the tumor may be established." This method of in sufflation has, I know, been advantageously used in determining the nature of doubtful abdominal growths. By these means and iu these directions search may often be advantageously made.