During the first sixteen years of my experience as an associate of Dr. Bloodgood, I took part in the diagnostic study and operation in 276 cases of lesions of the colon and of the rectum. In addition, I studied sections and roentgenograms in 125 cases of of similar lesions treated elsewhere, in which material was sent to the clinic for diagnosis. Table 1 summarizes these experiences.
In 136 of the 276 personally observed cases, approximately 50 per cent, and in 72 of the 125 cases in which we were sent material, approximately 60 per cent, cancer was present. In the former group, in the great majority of instances the cancer had reached the stage in which one could make the diagnosis by digital palpation and by inspection through a proctoscope when the rectum was involved or by study of a roentgenogram taken after a barium sulfate enema when the lesion