Observations and experiments on regeneration in Hydra viridis
Development, Genes and Evolution
Regeneration Y)uring the past three years, several papers have appeared dealing with regeneration and grafting in various species of Hydra. These papers have, in the main, formed the starting point for the following experiments which were made in the hope that they would throw additional light on the processes of regeneration and regulation in this form. The work was carried on during the winter of 1900--1901, under the direction of Professor T. It. MORGAN to whom I am indebted for helpful
... ed for helpful advice and criticism. I. Material and Method. The small green polyp, Hydra viridis, was used in all the experiments as it could be obtained in great numbers throughout the winter months, and also because it regenerates more quickly, and seems to survive more severe operations than does the larger form, Hydra grisea. A shallow dish with a thin layer of paraffine in the bottom was used in making all the experiments. The dish nearly full of fresh water, was placed on the stage of a dissecting microscope and the animals to be operated upon were then transferred to it. The polyps very soon attached themselves to the paraffine, and cuts were then made with a small sharp scalpel in any desired direction.