Cells in murine muscle have been reported to differentiate into hematopoietic stem and progenitor cells and thus repopulate the hematopoietic system of an irradiated animal. This activity was attributed to muscle stem cells. We used an in vitro and in vivo approach to identify the hematopoietic repopulating activity found in muscle tissue of mice by antibody staining and cell sorting. We confirmed existence of a hematopoietic repopulating cell in muscle tissue, but the data strongly suggest that repopulation is due not to muscle stem cells but to hematopoi-

The term projective tests is often used to encompass a variety of procedures that allow the target individual to provide free-form responses to ambiguous stimuli. The participant's responses are thought to be sensitive to implicit processes, and consequently they may be somewhat resistant to efforts at misrepresentation.This class of instruments has had a particularly checkered past. Because of concerns about honesty in responding to self-report measures, and the psychoanalytic belief that much of mental activity is resistant to self-observation, psychologists became enamored with the potential of projective instruments. The development of the Rorschach Inkblot Method (Rorschach, 1921(Rorschach, /1942 preceded formal discussions of projective psychological tests, but its popularity in the United States is largely attributable to its presumed projective qualities. The Rorschach was soon joined by other instruments, including the Thematic Apperception Test (TAT; Morgan & Murray, 1935;Murray, 1943), the Rosenzweig (1978) Picture-Frustration Study, and the Szondi Test (Deri, 1949). Even tests developed for other purposes came to be used as projectives, particularly the Bender Visual Motor Gestalt Test (Hutt, 1985). A 1959 survey found the three most commonly used psychological tests in clinical practice were projective tests (Sundberg, 1961).By the 1960s, though, the allure was fading for two reasons. One was the general critique of traditional personality assessment that emerged out of behaviorism. Mischel (1968) questioned whether the criterion-related validity of personality measures was sufficient to justify their use, whereas Goldfried and Kent (1972) criticized the practice of using latent constructs to account for associations between test behavior and behavioral outcomes. The second factor was a psychometric critique of projective methods (e.g., Cronbach, 1949;Entwisle, 1972; Swensen, 1957Swensen, , 1968.This second literature has engendered an enduring negative perception of projective instruments in the scientific community. Although surveys in the 1980s and 1990s found more than 75% of clinical doctoral programs required training in projective testing (Piotrowski & Keller, 1984;Piotrowski & Zalewski, 1993), a more recent update saw that rate drop to 59%, with more than half of program directors reporting reduced training in projectives (Belter & Piotrowski, 2001). A recent attempt to generate a list of discredited psychological tests was largely dominated by projective instruments (Norcross, Koocher, & Garofalo, 2006). Only a few instruments, primarily the TAT and Rorschach, continue to appear with regularity in the assessment research literature. The continuing popularity of the former can be traced at least in part to its successful use in motivational research (e.g., McAdams, 1982); that of the latter is directly attributable to the success of Exner's (2003) Comprehensive System, which brought uniformity in administration and scoring, normative data, and interpretation to the Rorschach.In contrast, alt...

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