SEPARATION OF FORM AND FXJNCTION 



167 



RECORD OF ANESTHESIA TIME IN MS 222 



Time in seconds for total anesthesia 

 EMBRYOS (Species ) 



RECORD OF RECOVERY TIME FROM MS 222 



Time in seconds or minutes for total recovery 

 EMBRYOS (Species ) 



Total Time Under Anesthesia. 



DEVELOPMENT OF FORM WITHOUT FUNCTION 



Anesthetics knock out the normal functioning of the nervous and/or the muscular system 

 but seem to have no effect on ciliary motion. It is instructive to determine to what extent 

 the muscular and the nervous systems can develop (normally) although the embryo is 

 under the continued influence of an anesthetic. 



Select a group of embryos of the same species and at an age and stage prior to the initia- 

 tion of muscular movement (see exercise on "Behavior Patterns"). In fact, the best stage 

 to begin narcosis for this observation is #14 for the Anura and #17 for the Urodela, when 

 there are as yet no soniites. Place them, five to a finger bowl of 50 cc. total volume, in 

 1/10, 000 MS 222 freshly made up in Spring Water for the Anura and Urodele Growing 

 Medium for the Urodela. Keep controls under the same conditions except for the anes- 

 thetic, and allow the embryos to remain undisturbed for periods ranging from 1 day to 2 

 weeks, at appropriate temperatures for the species considered. The Anura will do well 

 at laboratory temperatures but the Urodela should be kept at temperatures below 18°C. 

 For the extended observations, replace the experimental medium with fresh experimental 

 medium every 4-5 days, since there is some loss of potency of the MS 222 in solution. 



