OF THE BRAIN, ETC. 23 



in a graduated measure over quicksilver, with a 

 watery solution of potash. My friend Professor 

 Brande gave me his assistance in this part of the 

 present investigation, as he had done in many of 

 my former experiments. It will be observed, that 

 in estimating the proportion of carbonic acid, no 

 allowance has been made for that contained in 

 the atmospheric air; first, because the quantity is 

 so small that the omission can occasion no mate- 

 rial error; and, secondly, because the object was 

 to ascertain, not so much the absolute, as the 

 relative quantities, of carbonic acid evolved by 

 animals breathing under different circumstances. 

 The experiments which I shall first notice, 

 were made on the respiration of animals in a 

 natural state. 



EXPERIMENT I. 



Thermometer 65, barometer not noted. 



A young rabbit was allowed to remain under 

 the bell-glass during 30 minutes. The respired 

 air at the end of this time was found to contain 

 -Q of carbonic acid. 



It was ascertained that the rabbit occupied the 

 space of 50 cubic inches. 



The capacity of the bell-glass =502 cubic 

 inches. 



That of the gum-bottle 52 cubic inches. 



The air in the tubes and bladder =2 cubic 

 inches. 



Then 502 + 52 + 2-50 506_ 2 - * 



~W~ = 20~ 253 ' The 



c 4 



