AN EARLY axiom in tuberculosis warned against opening or manipulating tuberculous foci. In vitro, the mammalian tubercle bacillus assumes the aspects of a self-limited grower on the surface of solid nutrient mediums as well as on the surface of (and submerged in) liquid mediums.1 The spread of growth in vitro or in vivo, therefore, to some extent appears to be movement from external sources and not inherent in the bacilli themselves. Many modern procedures to benefit the patient take full cognizance of these facts and yet at times they are overlooked, as in surgical intervention, in which, unfortunately, evaluation is difficult or impossible. Earlier investigations demonstrated the detrimental effect of certain foreign materials2 and spreading agents3 on tubercle bacilli and on tuberculosis. With increasing use of surgical procedures, it becomes important to determine the effect of simple traumatism on the spread of tuberculosis, the significance of the