Summary and General Discussion 367 



indeed, what happens if the cord is cut within three quarters of 

 an hour after the start of asymmetry. But if the asymmetry has 

 been allowed to persist longer than this, and the time discon- 

 tinuity at forty-five minutes is too sharp for comfort, then the 

 asymmetry remains for hours or days after the cord is cut. Clearly, 

 physiological activity has been fixed in cord neurons; and one 

 has an obvious place to look for shifts in DC potentials across the 

 cord, in unit activity of motor neurons, in RNA and enzyme 

 content in various cells in the cord, and the like. Further, we are 

 examining the influence on fixation time of drugs which speed or 

 slow the formation of RNA, and Rothschild is making comparable 

 studies on the learning abilities of rats and mice in various maze 

 and avoidance situations. It does look as if 8-azaguanine, which 

 slows RNA formation, slows learning and prolongs fixation time; 

 and that a malononitrile dimer (Upjohn U9189), which is reported 

 to speed RNA formation, may have the reverse eflfect. But results 

 are still coming in and all this is very preliminary. 



In any event, inany workers are zeroing in on many prepara- 

 tions, including the flatworm, and we are really beginning to come 

 to grips with the problems of information processing" and storing 

 by the nervous system. 



DISCUSSION OF CHAPTER XV 



Ralph W. Gerard (Ann Arbor, Michigan): I would like to 

 invite questions and comments from those who participated in 

 the symposium. All those in the audience will wish to hear the 

 views of the participants on what some other speaker has said. 



Frank Morrell (Palo Alto, California): Dr. Gerard, may we 

 ask you to amplify the details of this beautiful experiment. I 

 would particularly like to know the details of how the operation 

 to produce asymmetry was done, whether drugs influence this, 

 and whether, for exainple, the same relations exist if such an 

 operation is performed using anesthesia. 



Gerard: The preparation is made using anesthesia, and time 

 is from the appearance of asymmetry, not from the time of the cord 

 cut. Anesthesia (ether or nembutal) is light, and the animal is ordin- 



