38 A CHEMICAL SIGN OF LIFE 
platinum wires fused into the side of the apparatus (see 
p. 113), these wires being connected in turn with the 
induction coil. Under this condition, when neither 
nerve is stimulated, the amount of the precipitate is 
equal in the two chambers. However, when one of the 
nerves is electrically stimulated with a weak induction 
current, the distance between the primary and second- 
ary coils being more than 
ro cm., an ordinary dry 
battery being used, not 
only does the precipitate 
appear sooner in the cham- 
ber containing the stimu- 
Fic. 2.—Glass weighing plate. 
A, B, platinum wires fused in the 
rear of the glass plate, with hooks; 
C, the nerve which is stimulated 
at D; G, the plate proper. Another 
piece of glass, exactly counter- 
lated nerve, but the 
quantity of the carbonate 
is much greater. This 
difference in carbon diox- 
balanced with this plate, is used, 
so that any wet tissue can be 
weighed very quickly. 
ide production can be 
brought out better in the 
quantitative estimate made 
in the manner described above. 
As shown in Table V, a stimulated nerve fiber 
of the spider crab gave 16X10 7 g. of carbon dioxide for 
TABLE V 
Amount of CO: Pro- Amount of CO: Pro- Rate of 
Nerve duced by 10 mg. of duced by 10 mg. of Therease 
Resting Nerve in Stimulated Nerve in of CO: 
to Minutes to Minutes 
Non-medullated (spider 
6.7X1077 g. (15°-16°)|16. X10 7 g. (14°-16°)| 2.4 times 
5.51077 g. (19°-20°)|14.2 X10 7 g. (20°-22°)| 2.6 times 
1o mg. of the nerve for ten minutes, while a fresh 
unstimulated nerve of the same animal gave only 
