Vol. 6, 1920 PHYSIOLOGY: MEDES AND McCLENDON 
245 
of the bell. They were also deprived of the manubrium in order to elim- 
inate the numerous mucous glands of that organ. The respiratory quo- 
tient was found to be about 95, and since the CO2 data are less accurate 
than the oxygen data, only the latter are given. It was found that nerve 
conduction in the bell was abolished in one-half per cent ether. The 
jellyfish died at the end of an hour in 3% ether but by limiting the ex- 
periment to one hour, reliable data could be obtained at this concentra- 
tion. Ether concentrations of one-half per cent, one per cent, two per cent 
and three per cent had no effect on the rate of respiration. 
Owing to limited time it was thought best not to run through a long list 
of anesthetics in a hurried manner with no basis for hopes that a change 
in respiration rate might be observed, but to look for one which had been 
reported to change the rate. Carbon dioxide has been considered by many 
biologists as an anesthetic and used to anesthetize lower animals. I 
had previously observed that an increase in hydrogen ion concentration 
of the sea water might lower the respiration rate of Cassiopea, but had not 
determined whether this was due to H ions alone or to an associated 
increase in CO2. The following experiments show that the metabolism 
is affected by CO2 and not by increase in H ions without increase in un- 
dissociated CO2 molecules. 
Although Tortugas sea water contains about 44 cc. CO2 per liter when 
estimated by adding acid and pumping it out, only a small fraction of this 
exists as CO2 molecules in the water, most of it being in the form of HCO3' 
and CO3" ions. If more CO2 is added to the water a large increase in un- 
dissociated CO2 molecules may be obtained. If HCl is added to the water, 
a limited increase in CO2 molecules may be obtained, due to decomposition 
of carbonates and bicarbonates. An increase in H ions without increase 
in CO2 molecules or even with decrease in CO2 molecules may be obtained 
by adding enough HCl to neutralize the alkaline reserve, pumping out the 
CO2 and adjusting the H ion concentration by minute additions of H3PO4. 
The results on relative rates of oxygen consumption after these methods of 
increasing H ions are as follows : 

8.2 
6.6 
6.3 
5.8 
5.7 
5.5 
By adding CO2 . . . 
100 
96 
92 
62 
41 
24 
By adding HCl 
100 
98 
70 
By adding HCl and re- 
100 
95 
In the above table the decrease of 5% in oxygen consumption after 
removing CO2 is well within the limits of error of the method and is strik- 
ingly different from the decrease of 38% on adding CO2 to obtain the same 
without removal of CO2. Therefore, the increased H ions are not re- • 
sponsible for the great fall in respiration after addition of C02- 
In conclusion it seems evident that all anesthetics may not act in ex- 
actly the same way or exactly the same on both plants and animals, and 
