Experimental dissociation of cells from hydra.

1. The cellular configuration of a hydra is dissociated under the pressure of a cover-glass and the different cell types are isolated and observed in hanging drop chamber. 2. With the exception of certain cnidoblasts, all the cells are rounded after dissociation of which only the nutritive muscular cells of the endoderm show amoeboid movement. 3. Pseudopodium originates as ectoplasmic out-pushing in which endoplasm flows in afterwards. Pseudopodia are thrown from all sides of the cell. 4. The details of intra-cellular contents in the different cell-types are described. 5. The nature of surface rigidity, attachment and cell shape before and after dissociation have been discussed in relation to the animal form and morphallactic power of hydra.