“…However, N orins and M ars hall (22) found that the intracardiac injection of 100-300 mg PHA (Wellcome) killed all of 12 mice, 3 rats and 8 guinea pigs injected. E lves, R oath and Israels (19) injected PHA-M intraperitoneally and subcutaneously into rats at weekly intervals. The rats were killed after 4 weeks and the spleens examined histologi cally, no abnormal changes being noted.…”