ON THE DIGESTIVE FUNCTION, &c. 



131 



ceases to secrete this fluid, at least in a state of perfect activity ; and that so 

 long as it is itself alive, it is capable, by its living principle, of counteracting 

 the effect of this solvent power. Yet a case has lately been published by Mr. 

 Burns of Glasgow, in which the stomach appears to have been eroded, 

 although the death, instead of being sudden, did not take place till after a long 

 illness and great emaciation of the body. It is possible, however, that even 

 here the stomach did not participate in the disease. That the living princi- 

 ple of the stomach is capable, so long as it continues in the stomach, of re- 

 sisting the action of the gastric juice, can hardly be questioned. And it is to 

 the superior power of this principle of life, that worms and the ova of insects 

 are so often capable of existing in the stomach uninjured, and even of thriving 

 in the midst of so destructible an agency. 



But though the solvent juice of the stomach is the chief agent in the pro- 

 cess of digestion, its muscular power contributes always something, and in 

 many animals a considerable proportion, towards the general result; and 

 hence, the shape and structure of this organ, instead of being uniformly alike, 

 is varied with the most skilful attention to the nature of the mechanism by 

 which it is to operate. 



In its general construction the stomach of different animals may be divided 

 into three kinds ; membranous, muscular, and bony. The first is common to 

 graminivorous quadrupeds, and to carnivorous animals of most kinds ; to 

 sheep, oxen, horses, dogs, and cats ; eagles, falcons, snakes, frogs, newts, and 

 the greater number of fishes, as well as to man himself. The second is 

 common to graminivorous birds ; and to granivorous animals of most kinds ; 

 to fowls, ducks, turkeys, geese, and pigeons. The third, to a few apterous 

 insects, a few soft-bodied worms, and a few zoophytes ; to the cancer-genus, 

 the cuttle-fish, the sea-hedgehog ; tubipores and madrepores. 



Of the membranous stomach we have already taken notice in describing 

 that of man ; and at the bony stomach we took a glance in a late lecture on 

 the teeth and other masticatory organs. It only remains, therefore, that we 

 make a few remarks on that singular variety of the membranous stomach 

 which belongs to ruminant animals, and on the muscular stomach of grani- 

 vorous and graminivorous birds. 



All animals which ruminate must have more stomachs or ventricles than 

 one ; some have two, some three ; and the sheep and ox not less than four. 

 The food is carried down directly into the first, which lies upon the left side, 

 and is the largest of all ; the vulgar name for this is the paunch. There are 

 no wrinkles on its internal surface ; but the food is considerably macerated 

 in it by the force of its muscular coat, and the digestive secretions which are 

 poured into it. Yet, in consequence of the vegetable and unanalogous nature 

 of the food, it requires a much farther comminution ; and is hence forced up 

 by the esophagus into the mouth, and a second time masticated ; and this 

 constitutes the act called rumination, or chewing the cud. After this pro- 

 cess, it is sent down into the second ventricle, for the esophagus opens 

 equally into both, and the animal has a power of directing it to which- 

 soever it pleases. This ventricle is called the bonnet or king's-hood; its 

 internal surface contains a number of cells, and resembles a honey-comb ; it 

 macerates the food still farther ; whicli is then protruded into the third ven- 

 tricle, that, on account of its very numerous folds or wrinkles, is called many' 

 plies, and vulgarly many-plus. It is here still farther elaborated, and is then 

 sent into the fourth ventricle, which, on account of its colour, is called the red^ 

 and by the French le caille, or the curdle, since it is here that the milk sucked 

 by calves first assumes a curdled appearance. It is thus that the process of 

 digestion is completed, and it is this compartment that constitutes the true 

 stomach, to which the others are only vestibules. 



There are some animals, however, which do not ruminate, that have more 

 than one stomach ; thus the hampster has two, the kangaroo three, and the 

 sloth not less than four.* Nor does the conformation terminate even with 



» Wiedemann, Arcbiv, b. I 



