Compressed Air; Low Pressures 767 



But the animal consumes oxygen, and consequently there is a 

 tendency towards a diminution of pressure in the apparatus. Now 

 pure oxygen, obtained by decomposition of water by a battery, is 

 contained in the graduated flask O, and by means of an apparatus 

 with constant level H, filled with a concentrated solution of calcium 

 chloride, the oxygen comes bubble by bubble to replace what was 

 removed by respiration. 



When the experiment is over, a simple reading on the graduated 

 bell gives the quantity of oxygen consumed; for the carbonic acid 

 produced, the potash solution is collected, and analyzed in the pres- 

 ence of an acid in the vacuum of the mercury pump. 



Experiment CCCXXVII. Rat weighing 360 gm., accustomed for 

 about ten days to living in the bell under a current of air, with its 

 food and its box. 



1.) December 23, at 3 o'clock, the experiment begins in ordinary 

 air. 



At the end of 24 hours, the experiment is stopped; we find that 

 the animal has consumed 12.360 liters of oxygen, and formed 7.310 

 liters of carbonic acid. 



The temperature of the rat before the experiment was 38.5°; 

 afterwards it was 38°. 



2.) December 25, at 4 o'clock, a current of oxygen is passed 

 through the bell in which the rat is kept and through the apparatus. 

 Then, since the system is closed, the pipettes are operated for a quar- 

 ter of an hour to mix the air of the different receivers. Then a sample 

 is taken which gives 87.5% of oxygen. 



After 24 hours, experiment stopped; the oxygen consumption was 

 11,352 liters; the carbonic acid production was 6.964 liters. 



Temperature of the rat: before, 38°; after, 37.5°. 



3.) January 3, at 3 o'clock, performed the experiment again in 

 ordinary air. 



In 24 hours, the oxygen consumption was 12.840 liters; the pro- 

 duction of carbonic acid 6.820 liters. 



4.) January 5, at 3 o'clock, experiment in air with 48.7% of 

 oxygen. 



In 24 hours, the oxygen consumption was 13.724 liters; the car- 

 bonic acid production 10.320 liters. 



Summarizing, if we change oxygen percentages to their equiva- 

 lents in barometric pressure, we shall say that there were 



At 1 atmosphere, 12.60 liters of oxygen consumed, 7.06 liters of 

 CO, formed. 



At 2.3 atmospheres, 13.72 liters of oxygen consumed, 10.32 liters of 

 CO ; formed. 



At 4.2 atmospheres, 11.35 liters of oxygen consumed, 6.96 liters of 

 C0 2 formed. 



