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174 the leaves of a book. In the sheep there are about forty of these leaves, and in the ox as many as a hundred.

Thence the food passes into the fourth stomach, commonly known as the red (abomasus), which is of considerable size, of a lengthened pear-like form, and having a hairy inner surface, with many large longitudinal wrinkles. This is the seat of digestion, properly so called: in the sucking young, it is the largest of the four.

The mode of acting of this complicated organ, Blumenbach has explained. The first three stomachs are connected with each other, and with a groove-like continuation of the gullet (æsophagus), in a very remarkable way. The latter tube enters just where the paunch and the second and third stomachs approach each other; it is then continued with the groove, which ends in the third stomach. This groove is therefore open to the first stomachs, which lie to its right and left. But the thick prominent lips which form the margin of the groove admit of being drawn together, so as to form a complete canal, which then constitutes a direct continuation of the gullet into the third stomach. The functions of this very singular part will vary according as we consider it in the state of a groove or of a closed canal. In the first case, the grass is passed, after a very slight mastication, into the paunch, as into a reservoir. ‘Thence it goes in small portions into the second stomach, from which, after a further maceration, it is forced into the gullet and thus returned into the mouth. On being again swallowed, the groove is shut, and the morsel of food is thereby conducted into the