Dr. Schultz
Dr. Schultz is the doctor that gave the injections to the rats (and mice) to make them smarter, stronger, increase their life span, and quicken their ability to learn. He is the doctor that sorted the groups and counted the rats and ended up with 63. Group A which contained Nicodemus, Jenner, Justin, Brutus, and the other rats that helped Mrs. Frisby, had 20 rats. Group B had 20 also while the control group had 23. He is older than George and Julie and seems to be their superior.