Difference between Autoclaved and Sterile Filtered Medium in Gulturing Fragments of a Marine Hydroid. ∗

Summary

Clava leptostyla, Agassiz, a marine hydroid, is good material for obtaining separated and migrating cells in tissue culture. A thorough washing of fragments in auto-claved sea water was sufficient to provide bacteria-free conditions. The behavior of the cells depended on the size of the fragments, the kind of medium and the amount of culture fluid. Fragments about 2 mm in length tended to close over along the cut edges thus preventing migration of cells. In 0.5 mm fragments the cells rounded up; underwent vacuolization and distintegration after 24 to 48 hours. In fragments about 1 mm in length migration of endodermal cells was observed but only in hanging drops of autoclaved sea water. Cell migration was never observed in cultures containing sea water sterilized by filtration with a Selas porcelain filter.