EXPERIMENTAL evidence for the importance of the role played by bacteria in producing "toxemia" and death in intestinal obstruction is briefly as follows: Dogs having isolated obstructed jejunal loops will die from a rather characteristic train of symptoms within a few days, usually four or five.1 When penicillin is either placed in such loops or administered parenterally to dogs in which such loops have been constructed, these dogs will be protected from "toxemia" and death for a significant period, sometimes for over a month.2 Succinylsulfathiazole, which is absorbed more slowly from isolated loops, will also protect animals with isolated obstructed loops when placed in the loops at the time of operation.3 One such dog was allowed to survive for over a year.3b Prior to the advent of potent antibacterial drugs for experiments of this type, the importance of bacteria as the cause of death was strongly