RATE OF REGENERATION IN CASSIOPEA 



17 



amount of the reagent present was sufficient to bring about any- 

 noticeable effect upon the activity of the sense organs. 



When medusae are treated with a weak solution of oxalic acid 

 in magnesium-free artificial sea water it is possible to destroy 

 the activity of the sense organs for a considerable time without 



Fig. 7 Curves to show the rate of regeneration of the halves of 40 disks, one- 

 half with and one-half without sense organs regenerating in sea water to which had 

 been added 15 parts of 0.6 m Mgso4. The upper (solid) line shows the regenera- 

 tion of the half disk with sense organs. The lower (broken) line shows regenera- 

 tion of the half disk without sense organs. The divisions along the ordinate 

 represent the amount of regeneration in millimeters. Those along the abscissa 

 the time of regeneration in days. 



seriously injuring the other tissues. In all my experiments, 

 however, recovery of functional activity by the sense organs took 

 place within twenty-four hours if the oxalic acid solution was of 

 such a strength that the ectodermal tissues were not injured. 

 In such experiments there was at first an equal rate of regenera- 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 21, NO. 1 



