22O 



DYNAMICS OF LIVING MATTER 



camel's-hair brush (Fig. 63), and gradually the whole fuses to a more 

 or less shapeless mass which flows back into the periderm, Fig. 64. 

 It follows from this that in this process certain solid constituents of the 

 polyp, e.g. the cell walls, must be liquefied. I pointed out the analogy of 

 these phenomena with Miescher's observations in the salmon. This un- 

 differentiated material formed from the polyp may afterward flow out 

 again, giving rise to a stem or a polyp ; to the former where it comes in 

 contact with a solid body, to the latter where it is surrounded by sea 



FIG. 63. 



water. This observation seems to indicate the possibility that the pro- 

 cesses of organization are reversible, in some cases at least. 



Giard and Caullery have found that a regressive metamorphosis 

 occurs in Synascidians, and that the animals hibernate in this condition. 

 The muscles of the gills of these animals are decomposed in their indi- 

 vidual cells. The result is the formation of a parenchyma which con- 

 sists of single cells and of cell aggregates resembling a morula.* 



Driesch found that when he isolated Clavellina that part of the ani- 

 mal containing the gills underwent a retrogressive transformation simi- 

 lar to that observed by Giard and Caullery, and that afterward these 

 masses gave rise to a new Ascidian.f The phenomena observed by 



* I quote this after Driesch, Archiv fur Entwickelungsmechanik, Vol. 14, p. 247, 1902. 

 t Driesch, loc. cit. 



