The points upon which stress has been laid, as distinguishing kid ney tumors of sufficient dimensions to be appreciable by manual examination, are these : That the large intestine is in front of the growth. This is not generally applicable, for, as Mr. Bruce Clarke" remarks, the colon is often displaced congenitally. This coincidence was found in a case which occurred under Dr. Black's care in St. Bartholomew's Hospital. As renal tumors grow in directions where the resistance is least, there is seldom anything like a lumbar pro jection; as Sir William Jenner remarked," "Tumors due to disease of the kidney enlarge in front; while abscesses and other lesions which may simulate renal tumors often cause considerable posterior projection." The kidney is rounded naturally and remains so as it grows; as Jenner observes, "it has no sharp edges and in disease never loses this peculiarity." Kidney growths are rarely influenced ma terially by inspiration. This, however, is not of universal applica tion, for as Morris says, "I have seen a renal tumor descend as much as an inch by a deep inspiration and fall' forward or backward by its own weight with the movements of the body." The shape of a tumor, if, for instance, it is a very pendulous one, may in some meas ure determine this, as I have had occasion to notice. The position of the most prominent portion of the tumor relative to the adjacent parts is also of importance to notice. This usually corresponds some where about with the line of the umbilicus. It should also not be lost sight of that on the right side alterations in the shape and posi tion of the liver have been mistaken for kidney tumors, while on the left the spleen and the corresponding kidney, in a similar way, have been confounded. A surface inequality, as, for instance, an interposed line of resonance on percussion, will often serve to indicate on careful examination these regional distinctions. Some of these diagnostic points are well shown in the accompanying figure from a paper on congenital sarcoma of the kidney by Mr. Paul."
Though in the majority of cases we shall be safe iu concluding that a kidney is the subject of a tumor, it may hardy be possible to differentiate between the varieties of uew growth in contradistinc tion to those dilatations and distentions of the organ which have oc cupied the earlier portions of this article. I may, however, mention some general conclusions derived from experience which may be of assistance in enabling us to make this distinction. The smaller kinds of innocent growths, which do not attain any considerable size, including cysts, are rarely discovered till after death; nor do they appear to cause symptoms or to be otherwise than incidental to other diseases. In the case of kidney symptoms occurring in syphilitic or scrofulous subjects, the possibility of a gumma or a tubercle will not be forgotten.
Turning to the malignant type of tumors, their often considerable size and rapid growth will not fail to arrest our attention. These in their development are either primary or secondary. The discovery of a primary malignant growth in any of the adjacent parts such as the rectum, prostate, bladder, intestines, or the breast, where the diagnosis is more readily made, will afford an explanation for the sequence of symptoms which now point to the kidney. Medullary cancer (sarcoma) in ; ;...................................dren when it affects the kidney, sometimes as sumes enormous dimen sions (vide Fig.28). When cancer involves the kid ney in a primary form it is usually limited to one, in secondary cancer both organs are generally im plicated. As stone in the bladder, as an irritant in a cachectic subject, is be lieved sometimes to be the exciting agent of a cancer, so may it be in the case of the kidney. A vinous growth in the bladder, as I have seen in more than one instance, is occasionally attended with a similar one in the kidney.