302 MORGAN. [VOL. II. 



If the same end is again cut off, there develops rarely one or a 

 few roots, but generally two or three vigorous stems. If the 

 operation is repeated a fourth time, one or two stems are with- 

 out exception produced. 



There is no statement made by Driesch as to how these 

 pieces were orientated with regard to gravity, but the results 

 show that another factor than gravity has an influence on the 

 regeneration. Unfortunately nothing is said with regard to 

 what has taken place at the other end of the piece. I shall try 

 to show that it is not improbable that this may be also a factor 

 in the result, and if so it is possible that Driesch's results are 

 due to this rather than to the action of the water on the free 

 basal end, or at least both factors may be present. 



My experiments were primarily undertaken in order to see 

 how pieces would behave when fixed to a revolving wheel, but 

 on account of the apparent disagreement between Loeb's and 

 Driesch's results, it was first necessary to repeat the experi- 

 ment of suspending pieces with two cut ends in order to see 

 how far gravity acted upon them. In one series of experiments 

 pieces were suspended in an aquarium by means of a silk thread. 

 Some of these had the apical end upwards, others the basal 

 end upwards, and still others were suspended horizontally. In 

 nearly all cases roots developed in the course of a few days 

 from both ends. If the ends were cut off, new roots developed 

 again on both ends ; although in one or two cases in which the 

 apical end was uppermost a stem developed at that end. The 

 pieces were from 3 to 5 cm. long. 



By means of another device the experiment can be much more 

 satisfactorily carried out. A small square piece was cut from a 

 sheet of cork and a hole bored in its middle. The end of a glass 

 rod, about 20 cm. long or longer, was pushed through the hole 

 in the cork. If the piece of cork is neither too large nor too 

 small, the glass rod, when put into an aquarium, will sink to the 

 bottom until one end touches, but the other end will be held up 

 in a vertical position owing to the buoyancy of the cork. 



Pieces of the stem of Antennularia were fastened to the 

 sides of the cork by means of two dried cactus spines, that were 

 crossed over the stem and stuck into the cork. 



