In establishing a diagnosis of renal tuberculosis, certain points of information are essential. Among these is the finding of tubercle bacilli in the urine of the patient suspected of having tuberculosis—in a catheter specimen from the bladder; or, better yet, from the urine obtained by means of a ureteral catheter from the renal pelvis itself.
At best, in certain cases, especially in those early cases in which a diagnosis is most desired, a satisfactory result is often difficult. In view of this fact, believing that positive smears should be obtained in a greater number of instances, Dr. E. G. Crabtree,1 of the genito-urinary service of the Massachusetts General Hospital, in 1914 employed the so-called dilution method for finding the tubercle bacilli. A modification of this method is now presented with the hope and belief that thereby the results may be further improved.
Before the advent of the dilution method, the