ON THE MORBID STATES DENOMINATED PNEUMATOSIS. 109 
foetus of several animals, while as yet in utero, a certain quan- 
tity of gas within the intestines. And M. Baumes (in his Traite 
des Maladies Venteuses), assures us of having made the same 
remark in the human foetus ; whence he concludes gases to be 
a product of exhalation of the intestinal mucous membrane. 
As to the gaseous fluids which find their way from without 
into the gastro-intestinal passages, they necessarily derive their 
source from the atmosphere, or from the food. It is evident 
that every time men and animals eat and drink, they must 
take into their alimentary canals a certain quantity of air min- 
gled wiih the saliva. It is likewise evident, that the aliments 
themselves introduce into the same passages a certain quantity 
of atmospheric air, adhering to the particles of food, or pene- 
trating them while under mastication. Lastly, some aliments 
there are which contain by nature, within their interstices, 
aeriform fluids, as the experiments of Gaspard shew. These 
are especially the vegetables belonging to the family legu- 
mina and crucifera, recognised commonly as being of a ventose 
nature. 
Aliments of this description introduced into the alimentary 
canal, into the vast stomachs of ruminants, and the capacious 
intestines of horses, give escape to such an abundance of gas 
that, through their accumulation and their expansion from the 
heat of the situation, they are capable even of occasioning death 
from the impediment they cause to the respiratory and circula- 
tory functions. The presence of gas, and its accumulation 
within the cavity of the uterus, in human medicine character- 
ized by the name of physomelra, is most rare with domestic 
females. The only cases in which we have been able to trace 
the presence of gaseous fluid in this reservoir are those, mal-a - 
propos named, uterine dropsy. We know that in this sort of 
cases evacuations take place from time to time of muco-puru- 
lent matters, which occasion remarkable sounds, caused by the 
presence of gases found mixed with them, and in which we very 
distinctly detect air-globules after their escape. 
(E.) Of Gases furnished by the Skin . 
The skin is also the seat of the continual exhalation of gas. 
With some animals, the frog especially, it is so abundant, ac- 
cording to Edwards, that it exceeds that which proceeds in the 
same animal from the surface of the lungs. We may be con- 
vinced of this by placing the living animal in water under- 
neath the glass of an air-pump. As soon as exhaustion is 
effected, there escapes a certain quantity of aeriform fluid. 
The body of man placed in a bath and exposed to the solar 
VOL. XXIV. Q 
