[As there has not been, as far as I am aware, any appropriate name given to this very remarkable part of the stomach of ruminants, I here take the liberty of suggesting the term _Gastro-duct_, by which epithet this muscular channel will be designated in the following pages.]
[Illustration: View of Gastro-duct, after Flourens.
_a._ A portion of the oesophagus cut open, showing the internal folds of the mucous membrane.
_b._ The opening of the oesophagus into the paunch.
_d, d._ Muscular fibres passing completely round the edge of the gastro-duct, and forming a sort of sphincter.
_e._ The opening from the gastro-duct into the third cavity.]
All these parts, namely, the oesophagus, the gastro-duct, and the first three cavities, not only communicate with each other, but they communicate by one common point, and that point is the gastro-duct. At the extremity of the third cavity, opposite to that at which the gastro-duct enters it, is an aperture which communicates immediately with the fourth cavity (_d_).
Such is a very brief description of the complicated stomach of the Ox Tribe. In what manner the food passes through this curious arrangement of cavities is a problem which has engaged the attention of naturalists from a very early period. A host of great men might be cited who have failed to solve it. The French physiologist, M. Flourens, by his recent experiments, has done more than any or all of his predecessors to give clearness and precision to this intricate subject.
The following is an abstract of the most important of his experiments:--
A sheep having been fed on fresh trefoil, was killed and opened immediately,--that is, before the process of rumination had commenced. He (M. Flourens) found the greatest part of this herb (easily recognised by its leaves, which were still almost entire,) in the paunch; but he also found a certain portion (_une partie notable_) of those leaves (in the same unmasticated state) in the honeycomb. In the other two cavities, (the many-plies and the reed,) there was absolutely none.
M. Flourens repeated this experiment a great many times, with herbs of various kinds, and the result was constantly the same: from which it appears, that herbaceous food, on its first deglutition, enters into the honeycomb, as well as into the paunch; the proportion, however, being considerably greater into the paunch than into the honeycomb. It appears equally certain that, in the first swallowing, this kind of food _only_ enters into the first two cavities, and never passes into the many-plies or the reed.