Carl M. Pearson was an energetic and exceptional physician–scholar-leader who founded, established, and broadened the Divisions of Rheumatology at University of California in Los Angeles (UCLA) beginning in 1956. His studies to induce myositis by injecting muscle saturated with the heat-killed tubercle bacillus, an emulsifier, and mineral oil (Freund’s adjuvant) enabled his report that polyarthritis occurred with Freund’s adjuvant alone in certain strains of rat and mice. This model of adjuvant arthritis allowed the next generation of studies to assess therapies for autoimmune diseases.