514 Dr. Davy’s observations and experiments 
and examined did not exceed ~ of a cubic inch, and I could 
not detect in it any traces of oxygene. 
After the experiments detailed in this Paper were made, 
on the absorption of different kinds of air introduced into 
the pleura, it appeared probable, on reflection, that mucous 
membrane, like serous membrane and the skin, might 
possess the power of absorbing air. In relation to this view, 
I thought it worth while to examine the air contained in 
the antrum maxillare and in the frontal sinus. I chose for 
the experiment the head of the sheep, in which these cavities 
are large, the openings by which they communicate with the 
atmosphere small, and the membrane with which they are 
covered, an active secreting surface. I collected the air by 
perforating the cavities under water about 15 minutes after 
the death of the animal. In two different instances the re- 
sults of the examination of the air were the following : the 
air from the antrum maxillare in one instance consisted of 
4.3 carbonic acid gas, 
13.0 oxygene, 
82.7 azote ; 
from the frontal sinus of 
*3-5 oxygene, 
86.5 azote, 
without any carbonic acid gas, the absence of which may 
have been owing to the presence of a good deal of mucus in 
the cavity, by which it might have been absorbed. In ano- 
ther instance the air from the antrum maxillare consisted of 
4.2 carbonic acid gas, 
13.8 oxygene, 
82.0 azote; 
