from the University of Maryland School of Medicine in 1891. After graduating Carroll studied bacteriology under Dr. William H. Welch at Johns Hopkins Hospital and assisted Walter Reed in pathology laboratories. Carroll and Reed later worked together at the Army Medical Museum in Washington and the Columbia University Medical School.
Carroll graduated from the University of Maryland School of Medicine in 1891. He studied bacteria under Dr. William H. Welch at Johns Hopkins Hospital and assisted Walter Reed in pathology laboratories. Later, Carroll and Reed worked together at the Army Medical Museum in Washington and the Columbia University Medical School.