The concept of "induction and elicitation," propounded by Stuart Mudd, circumvents the dangers of infecting the immunologically impaired individual without abrogating the effectiveness of the antigenic stimulus provided by an initial infection with living organisms. Mudd's concept utilizes the ubiquitous and naturally established delayed type hypersensitivity to Staphylococcus aureus as the primary induction step for the more effective use of bacterial fractions, such as staphylococcal phage lysate, a potent immunizing agent, commercially licensed and available, in the subsequent elicitation of a nonspecific, cell-mediated immune response. The results of an exploratory study in which induction and elicitation were applied as an immunotherapeutic modality, in combination with surgery, in a metastasizing animal tumor model (the F344 rat) are presented.