PHENOMENON OF REGENERATION IN EVERTED HYDRA

Abstract

1. Hydra may recover and continue to live after having been turned inside out. 2. The reactions to the turning may be classed in three groups: (a) "depression" and eventual dissolution; (b) re-turning; (c) regeneration through cell migration and without any re-turning. 3. Hydras that remain turned regain normality by the migration of the cells constituting the two layers of the body wall. 4. The migrating cells of each layer, individually or in groups, penetrate the mesoglea and filter between the cells of the opposing layer. 5. Hydras regenerated as described usually ingest food after 2 days from the time of turning.