440 
EXPERIMENTS ON DIGESTION. 
kind of decomposition, which is accompanied by a disengagement 
of ammoniacal gas. Perhaps the carbonate of soda in the saliva 
acting on the azootic organic materials may assist in accomplishing 
this purpose. A hydro-sulphuric acid gas is almost always dis- 
engaged during the maceration and softening of vegetable matter, 
whether green or dry. We have found a considerable quantity of 
this gas in the paunch of oxen and of sheep that have been fed on 
grass. According to Lemeyron and Fremy, it is found in consi- 
derable abundance with carburetted hydrogen and carbonic acid in 
the stomachs of ruminants that have fed principally on trefoil. It 
is possible that the decomposition of the gluten and albumen, and 
other similar matter contained in the trefoil, and in all other green 
herbs, may be the cause of the development of these gases. 
The aliment is very slowly softened in the paunch, or expelled 
from it. Carminati has never found this reservoir completely 
empty in sheep that have been kept six or eight days without food. 
The result has been the same in our own experiments; for, after 
we have kept sheep without food more than two days, we have 
found the paunch in a maimer filled both with hay and grass. 
The aliment contained in the paunch and mixed with the fluid 
secreted from its parietes, appears to pass, by little and little, into 
the reticulum. It would then appear that, by the contraction of the 
strong muscles of this viscus,the portion of the food already dissolved 
is forced into the maniplus through the narrow passage which forms 
a communication between it and the reticulum. The portion which 
still possesses any degree of consistence is retained in the reticulum, 
and assumes a globular form. This mass must be returned to the 
mouth to undergo a new imbibition of saliva and a more complete 
mastication. This constitutes the act of rumination. 
Rumination . — After the aliment has remained a certain time 
in the paunch, and has been sufficiently macerated in the alkaline 
fluid of that reservoir, rumination commences. Young animals 
who continue to suck, and whose food is derived entirely from the 
mother, do not ruminate; but this process commences with them 
as soon as they begin to eat any kind of solid food. 
During the act of rumination the animals are in a state of compa- 
rative repose. They are generally found lying down and resting 
on the left side. They neither ruminate when they are at work, 
nor when they are travelling, except the motion is exceedingly 
slow, or the work very light. A profound inspiration precedes 
the act of rumination. The pressure which the diaphragm, and 
probably also the abdominal muscles, exercise on the paunch and 
the reticulum, joined to the contraction of the strong muscular 
parietes of these stomachs, cause a globular mass of food to escape 
from them, and that, passing through the opening of which men* 
