extension; but complete extirpation with the knife, including the adjacent connective tissue and lymphatics, leaves behind no disease to be extended. Recurrence of the disease in this case would take place after cicatrization of the wound, and would be by new cell proliferation and not by extension. External cancerous tumors have been excised, and in the course of a few weeks the patients have died of internal cancer; but in such cases, if the internal had not antedated the external disease, the metastatic process had surely begun before the operation, and would scarcely have occurred had the tumor been excised five or six months before.
Since it appears from analysis of the observations of surgeons of long and vast experience that a large proportion of benign tumors in time become malignant, and that most malignant tumors have a stage of benignity, there should be no hesitation in advising the extirpation of these tumors as soon as discovered, and this advice may be regarded as the very essence of conservatism and of prophylaxis. From a purely æsthetic point of view it is of no little consequence to minimize scars resulting from the excision of tumors of the face, neck, arms, or hands, particularly those occurring in the gentler sex, and this can be best accomplished by the timely removal of such morbid growths as are likely to increase to the extent of greatly disfiguring the patients. It should, however, be noted that almost any scar is better than an ugly tumor.
The nævi that appear upon the faces of infants, though benign, often grow so rapidly as to constitute serious disfigurement, and to require operations which leave extensive scars. If before these little vascular tumors cover a space of more than two or three millimetres they are promptly destroyed with the thermo-cautery, the ensuing scar is likely to be almost imperceptible. The operation is completed in a few seconds, and the pain is very slight.
The greatest mischief arises from temporization in the case of small epithelial growths upon the lip. Any tumor of the lip of doubtful character should unhesitatingly be removed. As a general rule, the subsequent dissection and microscopical examination of the tumor shows the operation to have been justifiable. Early excision is the surest means of obtaining a long period of immunity from recurrence. The period of immunity from recurrence after operations is very variable even in the same species of tumors. Thus, in cancer the average is stated by some observers to be three years and a half, and by others seven years; the extremes are three months and forty years. The writer has reported cases in which the periods of immunity varied from seven to forty years. As soon as a tumor recurs, when it is still small,
