108 ON THE MORBID STATES DENOMINATED PNEUMATOSES. 
sequel of the softening of tubercles in communication with the 
bronchi. In this last state, the air proceeding from the lungs is 
constantly mingled with purulent and other matters. 
(D) Of the Gases of the Mucous Surfaces or internal 
tegumentary Tissues. 
Although we are assured of the existence of gaseous collec- 
tions in all organs lined with mucous membrane, such as the 
Eustachian pouches, the lung, the alimentary canal, the uterus 
and the bladder, it is more particularly within the lungs and ali- 
mentary canal that they are frequently observed. We give the 
name of pulmonary emphysema to the collection of air within 
the lung, to that within the alimentary canal the name of ab- 
dominal pneumatosis or tympanitis. As for the Eustachian 
pouches, it is the same with them as with the air-cells, it being 
only when their orifices are obstructed through some morbid 
condition that gaseous fluids remain in them. We then find 
them mingled with muco-purulent matter, furnished by the 
lining of the reservoir, and commonly collected within the 
reservoir. 
In the normal state, the stomach and intestines contain va- 
riable quantities of aeriform fluids ; and it is their accumulation 
in any considerable quantity that constitutes the flatulent or 
pneumatose condition. 
Gases spring from various sources. Some are the product of 
an exhalation going on from the free surface of the lining mem- 
brane ; others are introduced through deglutition along with the 
food, to which they in a manner adhere ; and there are some 
which are even contained in the alimentary matters, and which 
become disengaged during the process of digestion. 
The fact of the exhalation of gas from the internal surface of 
the intestine has been placed beyond doubt by experimentation. 
Messrs. Majendie and Girardin, having caused a portion of 
the intestinal canal of an animal to protrude from its abdomen, 
containing nothing, and secured it with ligature before and be- 
hind, they have found shortly afterwards the imprisoned por- 
tion of gut filled with gas; and all the while the mucous 
lining perfectly healthy. Bernard Gaspard, who has made 
the same remark, informs us that this gaseous exhalation is 
even more active than at the time of digestion. 
It is generally believed that this fluid is of use in continually 
preserving the form and dimensions of the intestines. If it be 
true, that the body of the foetus prior to birth does not admit 
any gas into the cells of its tissues, as M. De Blainville has 
asserted, it is no less certain that we have witnessed in the 
