This study of 424 primary malignant tumors of bone encountered at the Mayo Clinic during the past quarter century (1909 to 1934) was undertaken in response to the invitation of the "Sociedad Argentina de Cirugia" to one of us to participate in a symposium. We have reviewed the records, clinical and laboratory observations, roentgenograms, pathologic characteristics, treatment and results of treatment. We have had the cooperation of the pathologists in classifying 361 (85 per cent) of the tumors in these cases and in grading the malignancy of most of them. By careful follow-up inquiry we have traced 98.3 per cent of 424 patients over a period of three years and 96.5 per cent of 371 patients for five years after examination and first treatment (table 1).
The practitioner of internal medicine rarely encounters primary malignant tumors of bone and is compelled to depend on large medical centers or on group