614 FUNCTIONS OF ANIMALS. 



Carbonic acid gas. 



1st day, . 4 '64 per cent. 



2d . 4-70 



3d . 6-07 



4th . 3-27 



5th, . 5-26 



6th . 2-05 



7th . 2-39 



8th . 3-85 



9th . 3-05 



10th . 7-16 



The volume of carbonic acid gas, and, consequently, the con- 

 sumption of oxygen gas on the tenth day, was three and a-half 

 times greater than on the sixth day. The mean of the whole was 

 4*24 per cent. I made ten gentlemen, who were at that time 

 operative chemists in my laboratory, breathe into a glass tube 

 filled with mercury, and analyzed each portion of air thus ob- 

 tained. The trials were made about eleven o'clock of the day. 

 The results were as follows : 



Carbonic acid gas. 



Mr Thomas Thomson, (aged 14), 3-06 per cent 



Ditto, next day, . 3-61 



Mr J. Colquhoun, (aged 18), . 3-09 



Mr Forrest, (aged 18), . 2-10 



Ditto, next day, . . 5*19 



Mr Coverdale, (aged 18), . 2*54 



Ditto, next day, . . 1-71 



Mr Cargill, (aged about 30), . 4-68 



Mr Bruce, (aged about 20) . 5-46 



Dr Duncan, (aged about 21), . 6-17 



Dr Short, (aged about 40), . 6-85 



Mr Frazer, (aged about 30) . 7*08 



Two ladies allowed me to examine the air from their lungs. 



The result was as follows : 



Carbonic acid gas. 



First lady, . 2-85 per cent. 



Second lady, . 4-06 



The diversity in the volume of carbonic acid gas, and^conse- 

 quently of the quantity of oxygen gas consumed by respiration, 

 is fully as great as in my own case. The average of the whole 



