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fourth stomach. The glands, from which this fluid is secreted, are 

 very distinctly seen in the upper portion of the stomach of the deer ; 

 and in the lower portion are other glands, which secrete a fluid, to 

 complete the process of digestion by forming chyle. 



In the porpoise and whale tribe the two processes of solution and 

 chylification are completely separate, as there can be no doubt of the 

 food being dissolved before it arrives at the third stomach; since the 

 opening leading into that cavity is too small to admit anything but 

 fluids to pass, and the analogy between the second and third cavities 

 of the whale, with the two portions of the fourth of ruminants, is 

 very great. 



In the cod there are only two cavities, one for solution, with a 

 structure that bears a strong resemblance to that of the second ca- 

 vity of the porpoise, and having orifices similar to those in the pli- 

 cated portion of the stomach of the deer. Beyond this first cavity in 

 the cod, the food cannot pass till it is broken down ; so that the 

 analogy between the fish and the porpoise is very strong : in both 

 one and the other, solution is a step previous to the formation of 

 chyle, which is performed by secretions from glands of a different 

 structure, and applied to the food in a different cavity. And in this, 

 the bird, the fish, and the whale tribe, all agree. / 



The animals most nearly allied to the ruminants in their mode of 

 digestion are those which occasionally ruminate, as the hare and the 

 rabbit ; and in these also that part of the stomach nearest to the 

 oesophagus is never emptied, as happens in perfect ruminants. 



The next variety in the process of digestion is that of the beaver 

 and dormouse, in both" of which there is a glandular structure, pecu- 

 liar in quantity, which seems to correspond with the solvent glands 

 of other animals, and renders it probable that an increased secretion 

 of solvent liquor renders rumination unnecessary. 



Next to these follow animals with a cuticular reservoir, in which 

 the food macerates before it is submitted to the process of digestion, 

 as in the water rat, the common rat, and the mouse. In the first 

 there is a permanent division, but in the two last it is only muscular. 



The stomachs of the horse and ass are also very nearly allied to 

 these in their structure, and must be considered of the same kind. 



That of the kanguroo is peculiar, having pouches at its cardiac ex- 

 tremity lined with a glandular membrane. This stomach is, from its 

 unusual length, more capable of subdivision into a number of cavities 

 by muscular contraction ; and Mr. Home thinks this form likely to 

 facilitate regurgitation for the purpose of ruminating, which this 

 animal has been seen to perform. 



The other stomachs that are observed to have pouches at their 

 cardiac extremity are those of the hog, pecan, hippopotamus, and 

 elephant. That of the hog, excepting for a single pouch at its car- 

 diac extremity, would very much resemble those of the horse or rat. 



The stomachs that come next under consideration are those adapted 

 to digest animal food. In these there is little difference observable in 

 the cardiac portion (because animal substances are easily dissolved) ; 



