This stomach is nearly spherical, seven inches in diameter, of a
honeycombed appearance and glandular structure. The exit towards
the third stomach is placed very near the entrance from the first, and
is only five eighths of an inch in diameter.
The third cavity is also spherical, and two inches in diameter, with an aperture only three eighths of an inch in diameter, leading to a fourth stomach. This cavity is nearly cylindrical, like an intestine, but rather widest, measuring nearly three inches at its further extremity, and fourteen inches and a half in length.
The pylorus, which is the boundary of this stomach, is only one fourth of an inch in diameter. The dilated cavity into which this opens has been considered by Cuvier and Hunter as belonging also to the stomach; but Mr. Home observes, that it should rather he considered as duodenum, since the common duct of the liver and pancreas opens into it.
The common porpoise, the grampus, and piked whale, have also four cavities constituting the stomach; but in the bottle-nosed whale of Dale there are as many as six: the general structure, however, is the same; and in all the whale tribe there is but one cavity lined with a cuticle, as in the camel and bullock. In all of them the second cavity has a very glandular structure, and in all the third is very small. The fourth stomach also, in each of them, has a smooth internal surface, with orifices of glands opening into its cavity.
The first stomach appears not to be a mere reservoir, since the food undergoes a considerable change in it. The flesh is here entirely separated from the bones, of which several handfuls were found without the smallest remains of the fish to which they belonged; the orifices into the second and third stomachs being too small to admit the bones to pass. The bones must consequently be reduced to a jelly in the first stomach, but require a longer time for the completion of that process than the fleshy parts.
The second cavity is that which Mr. Hunter supposed to be the true digesting stomach; but Mr. Home, notwithstanding his deference for every opinion of Mr. Hunter's, is of a contrary opinion, from consideng that any further cavities would in that case be superfluous, after the complete formation of chyle, and from observing that the last cavity is that which, in its structure, bears the closest analogy to the simple human stomach, in which the process of forming chyle is certainly completed. From a comparison also of these stomachs with the fourth of the camel, it appeared that only the lower portion of that cavity is the stomach, in which the chyle is formed, and that its upper or plicated portion serves only to prepare the food for the process of digestion. [n the same manner also in the bullock, although there is not the slightest contraction or sub-division hetween the upper and lower portions, Mr. Home considers the plicated part as a mere preparatory organ, and the lower as that which secretes the proper gastric juice.
As the stomachs of the camel, bullock, and horse, farm principal links in the gradation from the most complex ruminating stomachs
