THE THEORY OF ANESTHESIA. 349 



observations were made by Loeb and Wasteneys 1 on the eggs of 

 another sea-urchin (Arbacia). In order to arrest cleavage by 

 cyanide (which directly inhibits oxidations) a concentration suffi- 

 cient to lower the rate of oxidation to one third the normal was 

 needed. The oxidations could be reduced to one half the normal 

 without arresting cleavage. But in solutions of various anaes- 

 thetics (chloral, urethane, chloroform, methyl, ethyl, and propyl 

 alcohols) of concentration sufficient to prevent cleavage entirely, 

 the rate of oxidation was found to be only slightly decreased, 

 on the average by less than 10 per cent. In solutions of urethane, 

 during the complete arrest of cleavage, the rate of oxidation was 98 

 per cent, of the control. When it is considered that oxidations 

 may be decreased by much more than 10 per cent, (by means of 

 cyanide, or by lowering the temperature a few degrees) without 

 arresting cleavage, it seems clear that the slight decrease of 

 oxidation observed in these experiments can stand in no causal 

 relation to narcosis. It is an accessory and apparently an unessen- 

 tial effect. Very similar results were found in experiments with 

 young fish embryos (Fundnlus) at a stage when the musculature 

 was well-developed, so that active contractions could be evoked 

 by external stimulation (e. g., by acidulated sea water). If 

 unstimulated, the embryos lie quiet within the egg-envelope; 

 the disturbing effects of variations in muscular activity are thus 

 absent. It was found that complete chloroform-narcosis had 

 little or no influence on the rate of oxidations; ether and butyl 

 alcohol caused some decrease in oxidations (25 per cent, to 30 

 per cent, at the narcotizing concentrations); but in order to 

 render the animals insensitive by direct inhibition of oxidation 

 through cyanide, it was found necessary to reduce the oxidations 

 to one ninth of their normal rate. In marine medusae (Gonio- 

 nemus) paralysis by cyanide required a decrease in oxidations 

 from three to six times greater than that accompanying urethane 

 narcosis. 



The insensitivity of many cells and tissues to simple abstrac- 

 tion of oxygen or presence of cyanide is in striking contrast to 

 their sensitivity to anaesthetics. Thus nerve-trunks only gradu- 



!Loeb and Wasteneys, Journ. Biol. Chem., 1913, Vol. 14, p. 517; Biochem. 

 Zeitschr., 1913, Vol. 56, p. 295. 



