104 ON THE MORBID STATES DENOMINATED PNEUMATOSES. 
also, it is probable, secrete gas with their habitual fluids ; and 
the cellular tissue itself generates gas in the case of emphy- 
sema, as well as serosity, and so likewise do serous surfaces. 
These general positions established, without stopping to in- 
quire into the distinction prescribed by M. de Blainville, the 
order I propose to observe is this : — 
In the first paragraph I shall exhibit the parts of the body 
in which gases are found, and this paragraph I shall divide 
according as they are met with ; viz. 
(A.) In the Blood. 
(B.) Cellular Tissue. 
(C.) The Serous Membranes. 
(D.) The Mucous Membranes. 
(E.) The Skin. 
In a second paragraph I shall treat of the physical and che- 
mical characters of the gas. 
In a third, of the physiological conditions of the production 
of gases, either as elements of the body, or as products, — 1st, 
of respiration ; 2dly, of nutrition ; 3dly, of digestion ; 4thly, 
of absorption ; 5thly and lastly, of the secretions. 
In a fourth paragraph, of the gases belonging to the diseased 
state ; of the morbid conditions under the influence of which 
gases are generated, and of the nature of the disorders which 
they beget. 
In a fifth and last paragraph, I shall offer some general 
considerations on the therapeutics of flatulent disorders. 
I. Of the Parts of the Body where Gases are found. 
The existence of gas has been demonstrated in the blood, in 
the cellular tissue, in the serous cavities, upon the surfaces of 
the mucous membranes, and upon that of the skin. 
A. Of Gases contained in Vessels, mixed or circulating with 
the Blood. 
Venous blood admits gases, as may be plainly proved, and 
in health too, and we know that they become accidentally intro- 
duced into it. 
Commencing with animals occupying a low station in the 
scale of animal existence, the tench for example, we ascertain, 
by opening the body of the animal under water, that there exists 
in its veins a notable quantity of aeriform fluid. And with- 
out a question, pulmonary absorption, in other animals, intro- 
duces gases into the venous system ; and chemistry has taught 
