DEPARTMENT OF MARINE BIOLOGY 



203 



than those for oxygen, only the latter are given in the following table. The 

 jelly-fish were tested 1 hour without anesthetic as a control. 



It may be seen from the above table that, within the hmits of error of the 

 method, the oxygen consumption was the same with or without ether up to 

 4 per cent ether, in which case death occurred before the end of the experiment. 

 Whether tliis is general for all anesthetics could not be determined, owing to 

 limited time and the fact that some anesthetics interfere with the Winkler 

 method. Carbon dioxid is sometimes considered an anesthetic, and the 

 following experiments were made by adding it to sea-water and then esti- 

 mating the total CO2 content from the alkahne reserve (0.025 N) and the Ph 

 (mean between Ph at beginning and end of experiment). 



From the above table it may be seen that the metabolism is progressively 

 lowered with the addition of CO2 to the sea-water. The question arises 

 whether the CO2 feund as bicarbonates and carbonates is effective. In order 



to study this, another series of experiments was made by adding HCl to 

 decompose these salts, but without addition of CO2 gas to the sea- water, as 

 follows : 



It may be seen from the above table that CO2 hberated from the salts of 

 sea-water lowers the metabolism. In order to test whether the hydrogen-ions 

 derived from hydrolysis of CO2 had the depressant effect, sea-water was de- 

 prived of CO2 after exactly neutralizing the alkahne reserve wdth HCl and 

 then acidified with a few drops of phosphoric acid. In the control the jelly- 

 fish used 2.9 c.c. O2, and in the C02-free sea-water of Ph = 5.9 they used 2.7, 

 which difference is within the limit of error. We may therefore conclude 

 that the Ph is not the controUing factor, but that CO2 lowers the metaboHsm. 



