244 
PHYSIOLOGY: MEDES AND McCLENDON Proc. N. A. S. 
might live some time after protoplasmic rotation had ceased, but such cessa- 
tion was an index that the lethal dose of anesthetic was approached, and 
it had the advantage of being observable in individual cells. 
If the experiments in which protoplasmic rotation had ceased are omitted 
we may be confident that we are dealing with living cells and may sum- 
marize the data in the following table : 
PERCENTAGE CON- 
CENTRATION 
ABSORPTION OP 02 
ELIMINATION OP CO2 
0 
VI 
0 s 
«s 
0 B 
X 
B 
PROTOPLASMIC ROTA- 
TION 
PHOTOSYNTHESIS 
0 
0 
a 
u 
0 H 
CO 
< 
it 
w 
Water 
100 
100 
100 
100 
100 
100 
Alcohol 
0.05 
100 
94 
100 
1.00 
112 
105 
100 
100 
75 
100 
1.50 
135 
125 
150 
105 
62 
99 
3.00 
189 
140 
500 
135 
44 
79 
6.00 
163 
175 
2000 
71 
00 
52 
Ether 
1.50 
150 
117 
200 
90 
49 
76 
3.00 
186 
133 
1000 
30 
12 
68 
Chloroform 
0.05 
113 
100 
1500 
130 
47 
91 
Chloretone 
0.05 
117 
150 
150 
71 
100 
100 
In the above table the results with 6% alcohol might best be omitted. 
Some shoots of Elodea seem to be injured by the alcohol and it seems 
probable that some dead cells may have been used in each experiment. 
Since rotation did not cease but was only retarded in the cells observed, 
these data are included to avoid criticism. In some cases rotation stopped 
in 3% ether. 
It may be seen from the table that all the anesthetics caused increased 
oxygen consumption and the greater the concentration of the anesthetic 
the more effective it was. There seemed to be some delay in the elimina- 
tion of CO2 as shown by successive time periods in the same experiment. 
This factor and the lesser sensitiveness of the method may be the reason 
cause for the failure of exact agreement between the CO2 and the O2 data. 
With marked increase in respiration there was also marked increase in 
exosmosis of chlorides as determined with the nephelometer. Protoplasmic 
rotation might be increased or decreased by the anesthetic, whereas photo- 
synthesis was always decreased. In higher concentrations of the anesthetic 
the size of the chloroplasts was markedly reduced. 
Since the effect of anesthetics on the conscious and automatic (rh3rthmical) 
centers in the central nervous system has been so thoroughly studied, it 
was decided to omit such data. Cassiopeas of about 15 cm. diameter 
were deprived of their automatic nerve centers by cutting off the margin 
