64 A CHEMICAL SIGN OF LIFE 
appear first on the barium hydroxide in the right cham- 
ber, containing the normal nerve, but the amount of 
precipitate later is seen to be much greater in this 
chamber than in the other. The narcotized nerve is 
giving off less carbon dioxide than the normal one. 
That the narcotized nerve produces less carbon dioxide 
than the normal is shown more strikingly by quantita- 
tive determinations. The average carbon dioxide output 
for the nerve when treated for ten minutes with a 4 
per cent ethyl urethane solution is less than 50 per cent 
of that of the normal nerve. At 20° to 22° C. the narcot- 
ized nerve gives 3.3X 1077 g. per centigram of tissue for 
ten minutes’ respiration, while the normal nerve, calcu- 
lated for the same units, produces 7.9X1077 g. One 
exception may be noted here—an experiment in which 
the respiration of the narcotized nerve was 4.91077 g. 
—hbut this is partly explained by the fact that the 
particular determination was effected at 25°C. Even 
in this case the decrease of carbon dioxide was marked. 
Qualitative experiments with a 2 per cent ethyl urethane 
solution show that even this concentration produces 
a diminution of carbon dioxide output. 
CHLORAL HYDRATE 
As indicated in Table VIII, a 2 per cent solution of 
chloral hydrate in sea-water partially or wholly para- 
lyzes the nerve in ten minutes and recovery is appar- 
ently perfect. A 3 per cent concentration produces 
complete paralysis and the return of excitability is 
good. Treatment with a 4 per cent chloral hydrate 
solution for the same period of time also produces 
paralysis, but recovery is not always good. In each 
