130 A CHEMICAL SIGN OF LIFE 
Description of Apparatus IIT —As shown in Fig. 5, 
the main part of this apparatus consists of only one glass 
bulb A, which serves the combined purposes of respira- 
tory and analytical chambers of the biometer. Its 
capacity is about 30 to 4o c.c., but can become smaller 
by introducing mercury in the same way as we managed 
in the other apparatus. The barium hydroxide tube d 
is inserted through its wall, and the three-way stopcock 4 
is attached to the bottom of the chamber. Just opposite 
the top of the barium hydroxide tube d there is another 
three-way stopcock 2, one arm of which is connected to 
the nitrometer C and the other arm of which is con- 
nected to tube B, into which the respired air is to be 
drawn for a subsequent analysis. This tube B is 
attached to a mercury burette G, by which the pressure 
in the tube and the chamber can be adjusted. The 
similar mercury burette H is attached to the chamber 
proper for the same purpose as well as for the means of 
driving air into the tube B. The remaining parts of the 
apparatus are exactly the same as in the biometer and 
are shown in the figure with dimensions. 
Method for quantitative determination of carbon dioxide 
with apparatus IIT —The detailed method is as follows: 
Open stopcocks 2 and 3 in such a way as to connect the 
chamber A and the tube B only. Fill the tube B with 
mercury by raising the mercury burette G. Close stop- 
cock 2 when a little excess of mercury is pushed over into 
the space in the capillary tube between the chamber A 
and the tube B and when the tube B is known to be 
absolutely free from any bubble of air. The closing of 
the stopcock must be done in such a way that there 
is a connection made between the chamber A and 
