344 T. H. Morgan and Abigail C. Dimon. 



(c) One electrode applied to one end, the other to the other 



end of the piece 28.0 



If we disregard the deflections caused by the electrodes, the 

 following are the departures from the normal: (a.) == — 3.6, 

 (b.) = +2.2, (c) = — 0.6. Theoretically, if (c.) were the re- 

 sultant of (a.) and (b.), it would equal — 1.4, but considering 

 how variable the conditions were always found to be, — 0.6 pre- 

 sents a fairly close agreement. In all other cases but one, where 

 similar tests were made, the results agreed in like manner with the 

 theory. 



REGENERATING WORMS. 



In addition to the readings made from worms that had been 

 freshly cut in two, a series of readings were made on worms in 

 which the process of regeneration had proceeded for a number 

 of days. The regenerating worms were divided into four groups : 

 ( I ) those in which a few anterior segments had been cut off and 

 regeneration was taking place at the anterior end of the long 

 piece; (2) those in which the worm had been cut in two in the 

 middle and regeneration was taking place at the posterior end of 

 the anterior piece; (3) those in which the worm had been cut in 

 two in the middle and regeneration was taking place at the an- 

 terior end of the posterior piece; (4) those in which the worm had 

 been cut in two at the fifteenth segment and regeneration was tak- 

 ing place at the anterior end of the posterior piece. They were 

 allowed to regenerate from twenty-five to thirty-two days, and in 

 the course of that time five or six tests were made on most of 

 them at intervals of a few days. One electrode was applied to the 

 regenerating tip, and the other to the old surface a short distance 

 from the tip. In all one hundred and fourteen readings were re- 

 corded, the results of which may be summarized as follows : 



Group (i) 31 cases, end positive ; 9 cases, end negative 



Group (2) 20 " " " 18 " 



Group (3) 15 II 



Group (4) 8 " " " 2 " 



Total 74 " " " 40 " 



