218 STUDIES ON RESPIRATION. V 



It is evident from these experiments that in animals the effect of 

 ether is of two types: (1) the decrease in the output of carbon dioxide, 

 which is reversible; (2) the increase of the output of CO2 which is 

 irreversible. 



It was shown by Loeb and Wasteneys'* that 1 per cent ether pro- 

 duces narcosis in the 1 week old embryos of Fundulus, and there can 

 be little question that this is also the case in embryos used in my 

 experiments. The question arises whether the decrease in the output 

 of carbon dioxide observed in 0.73 per cent ether is sufficient to pro- 

 duce narcosis. In order to test this, experiments were made to deter- 

 mine to what degree the temperature must be lowered in order to 

 reduce carbon dioxide output of 2 day embryos to the same point 

 as in 0.73 per cent ether (that is, to 57 per cent of the normal). It 

 was found that lowering the temperature from 22 to 13°C. pro- 

 duced the desired result. But it was observed that no narcosis was 

 produced by this drop in temperature, for when 8 day embryos were 

 similarly treated, their movements remained practically normal. We 

 must therefore conclude, as did Loeb and Wasteneys* from an ex- 

 periment on sea urchin eggs, that the decrease in respiration is wholly 

 inadequate to produce narcosis. It is therefore evident that the 

 action of anesthetics producing narcosis is due to some other cause 

 than the effect upon respiration. This is in complete agreement with 

 the striking experiments of Loeb and Wasteneys* on Fundulus em- 

 bryos, where they found that oxidation must be reduced to one-four- 

 teenth of the normal in order to produce narcosis. 



A comparison of the data obtained by the writer on the effect of 

 ether on the carbon dioxide production of tadpoles, aquatic insects, 

 frog eggs, and kilhfish eggs with those described in the preceding 

 articles of this series, as well as with those obtained by Haas,^ shows 

 that there exists a difference in plants and animals as regards the 

 effect of ether. With animals, in weaker concentrations, such as 0.73 

 per cent solution of ether, a decrease in the CO2 output takes place, and 

 the effect is reversible, while in stronger concentrations, such as 3.65 



^Loeb, J., and Wasteneys, H., Biochem. Z., 1913, Ivi, 295. 

 ^Loeb and Wasteneys, /. Biol. Chem., 1913, xiv, 517. 

 ^Haas, Science, 1917, xlvi, 462. 



