REGENERATIVE POTENCIES OF DISSOCIATED CELLS 

 OF HYDROMEDUS^. 



chas. w. hargitt. 



Introductory. 



At various times during my earlier work on the development 

 and regeneration of hydromedusae, especially that dealing with 

 the developmental capacity of egg fragments, there had grown 

 the conviction of the remarkable potencies of the various tissue 

 elements of these organisms. So strong had this impression 

 become that the desirability of repeating Trembly's picturesque 

 experiment of turning Hydras inside out and testing again the 

 possibilities that ectoderm and entoderm might really exchange 

 functions under the new conditions involved was entertained. 

 While admitting the rather convincing results of the experiments 

 of Ischikawa ('90), touching this feature it still seemed that 

 there might be some warrant that under certain conditions 

 Trembly's conclusions might find confirmation. However, the 

 writer never found the convenient season for trying out the 

 experiment, though other correlated features were observed at 

 various times in connection with the work above cited, especially 

 in the summer of 1908 while working on the development of 

 •Clava and Hydractinia. This was further incited by the work 

 ■of H. V. Wilson, "On Some Phenomena of Regeneration in 

 Sponges," '07. Therefore with the opportunity for investigation 

 at the Naples Laboratory I set about a series of experiments 

 with a view to settle some of the problems concerned. My work 

 at Naples began in December, 1910, and continued till mid-April 

 following, and during this period systematic experiments were 

 made upon the regenerative potencies of somatic cells of about 

 a dozen different species, among which the following may be 

 named: two species of Eudendrium, two species of Tubularia, 

 one each of Hydractinia, Podocoryne, Campanularia, Obelia, 

 Halecium, Sertularia, and a medusa, Liriope exigua. 



In Science of March 10, 191 1, appeared a preliminary report 



370 



