Atmospheric Air and Oxygen Gas by Respiration. q6i 
Here was an increase of six parts in 100 of something which 
the tests for oxygen would not take up, and also a loss of six 
per cent, oxygen. This seemed to convince us, that under 
certain circumstances, as during some peculiar alteration in the 
vital functions, gaseous oxide of carbon, carburetted hydrogen, 
or some other gas not absorbabie by lime water or the tests 
for oxygen, might be given off from the lungs, and we accord- 
ingly determined to repeat Cruikshank’s experiments with 
hyperoxygenised muriatic acid gas. 
We procured the gas from hyperoxygenised muriate of 
potash by means of muriatic acid, and mixing it with a known 
portion of gaseous oxide of carbon in a flint stopper bottle, 
the mouth of which was immersed in mercury for twenty- 
four hours, the gaseous oxide of carbon was converted into 
carbonic acid gas, as was proved by its effects upon lime 
water, which, when both the gasses are pure, absorbs them 
entirely after they have remained together for twenty-four 
hours ; it was plain, therefore, that we had the means of 
detecting gaseous oxide of carbon, and doubtless carburretted 
hydrogen, if any should be contained in the expired gas. 
From a conviction of the importance of these experiments we 
were determined to take nothing upon trust. 
Fifteenth Experiment. 
We repeated the 14th experiment with a little variation. 
In this case we employed only one of the mercurial gaso- 
meters, into which exactly 300 cubic inches of atmospheric 
air were admitted. The operator having made an easy ex- 
piration, applied his mouth to the cock at the top of the bell 
glass, and the time being noted, began to breathe ; in less 
