Realizing, then, that the mortality of cancer is materially and steadily rising, in spite of most diligent research by innumerable honest and capable scientists, with the expenditure of vast sums of money and countless animal lives, and in spite of the work of ardent, earnest, and capable surgeons, who have failed to stay the terrible progress of the disease, let us briefly study some of the reported statistics in regard to the results of operative interference in cancer. It may be first stated that this is a most difficult task, so different are the reports from different surgeons. There are many elements which affect the statistics relating to the surgery of cancer. First of these is, perhaps, the stage of the disease at which the operation is performed. Second, the results vary, of course, immensely with the knowledge and skill of the operator and the excellence of the technique. Third, the class of cases operated on has much to do with favorable or unfavorable results reported. Fourth, the length of observation after operation is always to be considered in connection with surgical statistics. Finally, the optimism of the reporter must be regarded in weighing the true value of reports as to ultimate results. We will briefly consider these points. First, as to the stage of the disease at which the operation was performed. We have seen in this and previous lectures that the lesion which we call cancer is but a _result_ of a deranged blood state, and is not a purely local process, a something simply to be removed surgically in order to have the patient get well and remain well. For one sees plenty of cases where there were recurrences even after the very earliest operations possible. But the claims put forth that favorable results are conditioned on very early operations are so strenuous and persistent that we must believe that a measure of the favorable results can be thus accounted for. We know, of course, that very late in the disease operations are out of the question. It is a little curious, however, that most of the pictures shown, statistics presented, and arguments adduced by these ardent advocates of early operation relate to cancer of the skin, especially about the face, which cause hardly 2 per cent of all the deaths from cancer in various countries; whereas those who see much of cutaneous epithelioma know that if properly handled it is generally a comparatively mild affair and relatively easily cured without surgical operation, as you have so constantly seen in this clinic in past years. But mortality statistics are greatly influenced by the class of cases which the operator takes, and so if epithelioma of the skin is included, the ratio of cures will be high. Selected cases also always give more favorable statistics.