On Respiration. 385 



8 cubic inches ; the air left in the lungs, after complete 

 expiration, would therefore be 108 cubic inches 3 but the 

 mean of our experiments would make it 183. 



Experiment 1. 141 



2, 22.5 



3, 236 



4, 133 



We are then almost compelled to allow that when p^ire 

 oxygen is respired, a portion of azote is given off from the 

 blood. 



We now resolved to perform a series of experiments 

 upon some animal which lived wholly upon vegetable food, 

 and made choice of the Guinea pig as one of the most ma- 

 nageable. 



The apparatus consisted of our two large mercurial gaso- 

 meters, which were made to communicate with a strong 

 trough E, in the middle of which a small mahogany table D 

 was made fast by a screw, for the purpose of supporting the 

 animal under the bell-glass A; twohofe were made through 

 the table for the insertion of tubes to supply and take off 

 the air, each of them communicated with one of the mer- 

 curial gasometers ; the tube B delivered gas towards the 

 upper part of the glass A, in order to bring the supply of 

 fresh air near the head of the animal : the opening of the 

 tube C was placed within half an inch of the table to coti- 

 vey off the respired air; the gasometer connected with this 

 tube was made to communicate with a mercurial bath G, 

 in which portions of the respired air were preserved for ex- 

 amination. Quicksilver being poured into the trough E, 

 so as to rise to a level with the top of the inahogany stand, 

 we placed a Guinea pig upon it, with the bell-glass over 

 him, and as its edges were immersed in quicksilver, the 

 animal was completely confined in atmpsphenc air : we 

 found that his body occupied the space of 39 cubic inches, 

 which deducted from the cubic contents of the glass A, left 

 53 cubic inches for the air confined with the pig, to which 

 must be added 3 more for that contained in the tube C. 



First Experiment with Atmoapheric Air. 

 The pig was placed upon the stand, and the apparatus 

 arrau'^ed as represented in the plate : 250 cubic inches of 

 VoT. 34.No. 139. JVou, J8O9. Bb almospheri9 



