THE AMOEBOID MOVEMENT OF DISSOCIATED 



SPONGE CELLS. 1 



PAUL S. GALTSOFF. 



INTRODUCTION. 



In 1907 H. V. Wilson discovered a very interesting case of 

 regeneration in siliceous sponges from dissociated tissue cells. 

 The same phenomenon was observed in Hydroids, Alcyonaria. 

 and Asteriae (Wilson, 1911), in fresh water sponges (K. Miiller, 

 1911) and in calcareous sponges (Huxley, 1920). 



Twelve years before Wilson's discovery Roux (1895) described 

 a similar phenomenon. He found that the blastomeres of the 

 frog egg, artificially separated at an early stage of segmentation, 

 and placed in water a short distance apart, slowly approached 

 one another until they came into contact. Roux called this 

 phenomenon cytotropism to correspond with other tropisms 

 known in the scientific literature. He regarded cytotropism as a 

 special case of chemotropism. This opinion was based on theoret- 

 ical considerations as no experiments were made to prove it. 



The term cytotropism although not definitely accepted has 

 been used in various text books and scientific papers. - Apparently 

 the sponges with their ability to form the conglomerates from the 

 dissociated cells afford the best opportunity for a study of this 

 phenomenon. 



Wilson and Miiller (I.e.) made their studies on the regenera- 

 tion of sponges after dissociation only after the aggregates began 

 to form. Prior to this they made no exhaustive study, and merely 

 stated that the separated cells coalesce and form aggregates. 

 They did not study the amoeboid movement which leads to the 

 coalescence of cells and which is the main purpose of the present 

 investigation. The work was started in 1920 at the Marine 

 Biological Station at Sebastopol (Black Sea) and continued in 

 1921 at Woods Hole and in the Zoological Laboratory of Columbia 

 University. 



1 Contributions from the Sebastopol Biological Station, Crimea, and the Marine 

 Biological Laboratory, Woods Hole, Mass. 



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