Aeromonas hydrophila was enteropathogenic in ligated ileal loops of rabbits, causing a fluid accumulation of 1-0 - 2-0 ml per cm of gut length. Gut reaction could be produced with an inoculum as low as 10-4 viable bacteria. There was no difference in the nature of the positive reactions given by strains isolated from diarrhoeal and non-diarrhoeal children and adults and from water. Plesiomonas shigelloides, on the other hand, did nt cause a significant gut reaction. A. hydrophila multiplied in the ileal loop by about 10-5 wheras P. shigelloides did so at only 10-2-3. These experiments on a animal model thus indicated the enteropathogenic nature of A. hydrophilia, but no definite conclusion could be drawn from this study on P. shigelloides.