168 



SEPARATION OF FORM AND FUNCTION 



RECORD OF ANESTHESIA TIME IN MS 222 



Time In aeconda for total anesthesia 

 EMBRfOS (Species 



RECORD OF RECOVERY TIME FROM MS 222 



Time In second or minutes for total recovery 

 EMBRfOS (Species 



TOTAL TIME UNDER ANESTHESIA 



DEVELOPMENT OF FORM WITHOUT FUNCTION 



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

 tem 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 la 

 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 

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

 stage to begin narcosis for thla observation is #1^*- for the Anura and #17 for the Urodela, 

 when there are as yet no somites. Place them, five to a finger bowl of 50 cc. total vol- 

 ume, In l/lO,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 anesthetic, 

 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 

 obaervatlons, replace the experimental medium with fresh experimental medium every k-^ days, 

 since there is some loss of potency of the MS 222 in solution. 



Upon returning the embryoa from prolonged narcosis to normal medium, determine the 

 speed of recovery of response but more particularly compare the stage of development with 

 that of the controls. Note any morphological and behavior variations when compared with 

 the untreated contiX5ls. Have the muscles developed normally In spite of total anesthesia? 



