There are two important epochs in the surgical history of mammary carcinoma. The modern operation, based on the knowledge of the lymph-vascular drainage of the breast, has raised the percentage of ultimate cures, as the introduction of antiseptics and asepsis lowered its primary mortality. This is the more remarkable in view of the extensive operation now performed, so that the reduction of the primary mortality of 25 per cent. in preantiseptic days to less than 1 per cent, with modern technic is approximately parallel to the reduction in local recurrences from 65.6 per cent. to 6.5 per cent. Elaboration of Halsted's principles has carried the operative incision further and further away from the primary focus of disease until the limits of surgery must surely have been reached, with results that are highly disappointing save when compared with results of past decades. Why must the ultimate cancer be sought for in