The rhetorical aspects of psychotherapeutic theory may be examined by arranging the canons of rhetoric, the sources of persuasion, and some procedures of rhetorical behavior on one axis of a grid, then placing rhetorical/therapeutic situations on the other axis of the grid. In this way, the degree to which a rhetoric is used in psychotherapeutic interviews can be measured. This methodology was applied to the theory and therapeutic procedures of Harry Stack Sullivan, a noted psychotherapist. Although the rhetoric behind Sullivan's theories and procedures was found to be only partially complete, the study's methodology offers a way to begin remedying such incompleteness, enabling researchers to devise and refine strategies for use in predictable, therapeutic situations and to adapt familiar rhetorical criteria to therapeutic situations. (RL)