FOOD AND THE NERVE-NET 



147 



TABLE 3. 



TIME IN SECONDS FOR THE TRANSFER BY THE TENTACLES OF METRIDITTM OP 

 SMALL PIECES OF MUSSEL TO THE MOUTH WHEREUPON THEY WERE RE- 

 MOVED AS THEY WERE ABOUT TO BE SWALLOWED. SIXTEEN TRIALS WERE 



MADE ON THE LEFT SIDE AND THEN THE SAME NUMBER ON THE RIGHT. 

 oo INDICATES A DISCHARGE OF THE PIECE OF MEAT AT THE PERIPHERY 

 OF THE ORAL Disc. 



ments, in which the fragments of mussel delivered to the 

 tentacles of the first side were allowed to be swallowed 

 instead of being removed, the tentacles of the opposite 

 side very regularly exhibited a decline in responsiveness. 

 It is, therefore, believed that this change is due to the 

 food introduced into the digestive cavity, and, since the 

 pieces of food were very small, not to the accidental 

 transfer of food juices from the side of the disc stimu- 

 lated to the other, as suggested by Gee (1913). 



To remove any doubt on this point a modification of 

 an experiment tried by Gee (1913) was adopted and by 

 means of a fine glass syringe a considerable amount of 

 mussel juice was injected through the column wall of 

 small specimens of Metridium into their digestive spaces. 

 This operation was easily accomplished, especially if the 

 region through which the puncture was made was pre- 

 viously anesthetized with magnesium sulphate. The in- 

 jected juice apparently did not escape from the mouths 

 of the animals, which, however, took in a considerable 

 amount of seawater and enlarged, much as well-fed ac- 

 tinians do. After an hour or so the tentacles of the in- 

 jected actinians were tested with fragments of mussel and 



