on the Generation of Animal Heat. 407 



circular groove of the wooden stand. In the upper part of 

 the bell-glass is an opening, admitting a tube connected 

 with the bladder C. 



D. Is a bottle of elastic gum, having a brass stop-cock 

 E connected with it. 



F. Is A silver tube, of which one end is adapted to receive 

 the tube of the stop-cock E, while the otiier extremity, 

 making a right angle with the rest of the tube, passes 

 through a hoie in the wooden stand, and projects into the 

 cavity of the bell-glass, where it makes a s^econd turn also 

 at a right angle, and becomes of a smaller diameter. In the 

 upright part of the tube is an opening G. 



The tubes are made perfectly air-tight, where connected 

 with each other, and with the rest of the apparatus, and 

 the circular groove is filled with quicksilver. 



The capacity of the bell-glass, allowance being made for 

 the rim, which is received in the groove with the quick- 

 silver, is found to be 302 cubic inches. The capacity of 

 the gum-bottle is 52 ^ubic inches, and in the calculations 

 after the experiments two cubic inches have been allowed 

 for the air contained in the diftevent tubes, and for the 

 small remains of air in the bladder after being nearly 

 emptied by pressure. 



Mode of using the Apparatus. 



In order to ascertain the quantity of air consumed under 

 ordinary circumstances, the animal w as placed on the stand 

 under the bell-glass, the bladder being emptied by pressure, 

 and the gum-bottle being distended with atmospheric air. 

 During the experiment, by pressing occasionally on the 

 gum bottle, liie air was forced from it into the bell-glass. 

 On removing the pressure, the gum-bottle became filled by 

 its own elasticity with air from the bell-glass. Thus the 

 air was kept in astate of agitation, and thedilatation of the 

 bladder prevented the air being forced through the quick- 

 silver under the edoe of the bell-glass. At the end of the 

 experiment, the gum-bottle was completely emptied by 

 pressure, and allowed to be again filled with air trom the 

 bell glass ; this was repealed two or three times, and the air 

 in the bottle was then preserved for examination. The 

 proportion of carbonic acid being ascertamed, and the 

 capacities of the different parts of the appnratus, and the 

 space occupied by the amm;il being known, the total quan- 

 tity of carbonic acid formed, and consequently of oxygen 

 consumed, was easily estimated. 



When the experiment was made on an animal in whom 

 C c 4 the 



