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