17. THE EMBRYO AND NARCOSIS, OR 

 THE SEPARATION OF FORM AND FUNCTION 



PURPOSE: To determine the efficiency of various depressants as embryonic narcotics, 

 and to utilize such narcotics in an attempt to separate the development of form from 

 function. 



MATERIALS: 

 Biological: 



Technical: 



Early Anuran or Urodele embryos through stages of (muscular) motility, 

 (Anura stage #17, Urodela stage #27). 



Various known depressants: (None of these except freezing affect the 

 cilia) 



Acetanilid - 1/1, 000 (lethal at 1/200) Rapid recovery 



Alypin 



Amyl alcohol - 0. 15% 



Barbital sodium - 1/100 (lethal at 1/15) Slow recovery 



Borocaine 



Butyl alcohol - 0. 6% 



Chloral hydrate - 0. 1% or 1/500. Rapid recovery 

 *Chloretone - 0. 2 to 0. 9% or 1/20, 000 (lethal at 1/2000) Rapid re- 

 covery 



Chloroform - 0. 05% Rapid recovery 



CO2 gas 



Cocain 



Diethyl ether - 1.4% 



* Ethyl alcohol - 4. 6% or 1/50 Rapid recovery 

 Ethyl chloride - 0. 046 moles/liter 



* Ethyl urethane - 2. 0% (Not suitable for prolonged exposure unless 



in weaker concentrations, i. e. , 1. 0%. ) 

 Freezing 



Methyl alcohol - 6. 4% 

 *MS 222 (M-Amino-Ethyl-Benzoate) - 1/3000. Can be autoclaved. ** 

 Nembutal - 1/750 Slow recovery 

 Novocaine 

 Panthesine 



Paraldehyde - 1/400 (lethal at 1/100) 

 Propyl alcohol - 1.5% 

 Stovaine 

 Tutocain 



METHOD: 



Precautions: 



1. To function as an anesthetic, a drug must interfere with some physiological 

 process such as respiration or enzyme activity. The action of untested drugs 

 must not be prolonged beyond the stage of total anesthesia unless testing for 

 its persistent effect or lethality. 



2. All depressants are immediately lethal in high concentrations. In very low 

 concentrations, and repeated immersion, the embryo may become increas- 

 ingly resistant to narcosis. 



* Suitable for these experiments. 

 ** Available through M. Sandoz G Co. , 68 Charlton St. , New York City. 



165 



