Researcher and teacher Mitchell Halperin worked in one of the more complex corners of medicine. As a nephrologist – kidney doctor – at St. Michael’s Hospital in Toronto for 50 years, he taught and conducted basic research on renal physiology related to fluid, electrolyte and acid-base homeostasis. “He had an ability to put things in perspective, to put across concepts that were intellectually challenging. He could distill them down to their simple fundamentals, so even a child could see,” says Tony Fields, who learned from Dr. Halperin at St. Michael’s Hospital and the University of...