It has already been shown by the illustration, (p. 4,) that the paunch is the largest of the four cavities; but this is not the case with the stomach of the young calf, which, while it continues to suck, does not ruminate; in this case the reed, which is the true digestive cavity, is actually larger than the other three taken together.
When the calf begins to feed upon solid food, then it begins to ruminate; and as the quantity of solid food is increased, so does the size of the paunch increase, until it attains its full dimensions. In this latter case, the paunch has become considerably larger than the other three cavities taken together.
A curious modification of an organ to adjust itself to the altered condition of the animal is beautifully shown in the instance now under consideration, the nature of which will be easily understood by a reference to the following diagrams, giving the exact relative proportions of the different cavities of the stomach to each other in the young calf and in the full-grown cow.
[I am informed by Professor Symonds, of the Royal Veterinary College, that the two following sketches should be placed in the page so as to be viewed with the œsophagus to the right, and the pylorus to the left, instead of being, as they now are, at the top and the bottom; but as the present object is only to show the relative sizes of the different cavities, the error is not of much consequence.]
The letters refer to the same parts in each figure: a, the paunch; b, the honeycomb bag; c, the many-plies; d, the reed.
Outline of the Stomach of a Calf about a fortnight old.
