1. The Shigella organisms isolated so far from apes and monkeys cannot be distinguished from those harbored by human beings. 2. The Shigella isolated from apes, including the gorilla, and monkeys at large is mostly polymicrobial. This finding seems to be very significant. 3. It seems that the Shigella organisms detected from apes and monkeys, especially from the gorilla, are little pathogenic by themselves. 4. There are considerably great differences among apes and monkeys in susceptibility to Shigella organisms. 5. These Shigella organisms harbored by apes and monkeys can be extirpated with ease by proper administration of antibiotics and chemicals.