Our Humble Helpers: Familiar Talks on the Domestic Animals

by Jean-Henri Fabre

CHAPTER XXXII

RENNET

“In the making of cheese the first step is to cause the milk to curdle. Lemon juice, vinegar, or any other acid would bring about this result, as we have already seen; but it is customary to make use of another and much more efficacious liquid called rennet. Let us learn first what this liquid consists of. That calls for certain explanations apparently foreign to our subject, but nevertheless leading directly to it.

Typical Ruminant Stomach

“Among our domestic animals three, the ox, goat and sheep, are remarkable for their horns and split hoofs. All three have a way of eating very different from that of other kinds of animals. The dog, for example, after masticating its food sufficiently, swallows it once for all and passes it into a single digestive cavity called the stomach, where it becomes a fluid mass suitable for nutrition. On the contrary, the goat, sheep, and ox chew and swallow the same food twice; at two different times, with a rather long interval between, the same fodder is subjected to mastication and passed down the throat. [[312]]

“Animals are characterized as ‘ruminant’ that, after chewing their food once and letting it pass into the digestive cavity, bring it back into the mouth for a more complete trituration. The ox, goat, and sheep are ruminants. Instead of only one stomach they have four, that is to say four membranous pouches where the alimentary matter passes from one to another before being converted into a sort of nutritive soup.

“The first of these pouches is called the paunch. It is a spacious cavity in which the animal accumulates the fodder that has been hastily browsed and not thoroughly chewed. Its inside surface is thickly covered with short flat filaments that give it the appearance of coarse velvet.

“Watch the ox and sheep in the pasture. They crop the grass without stopping, without a moment’s rest; they chew very slightly, very hastily, and then swallow; one mouthful does not wait on another. It is the time for filling the paunch without losing a bite by prolonged chewing. Later, in the hours of repose, there will be leisure for bringing up again the food swallowed and for grinding it to the proper fineness.

“This receptacle known as the paunch having received its due supply of fodder, the animal retires to a quiet spot, lies down in a comfortable position, and takes up at its ease, for hours at a time, the work of chewing. This second stage in the preparation of the food under the millstone of the teeth is called rumination. The ox is then seen patiently chewing, [[313]]with an air of gentle satisfaction, without taking anything from outside. What is it eating thus, when there is apparently no fodder within reach? It is re-eating what has been stored up in the paunch, and which now comes up from the bottom of the stomach in little mouthfuls. Then the motion of the jaws ceases, the mouthful is swallowed, and immediately after something round and bulging is seen making its way upward under the skin of the neck. It is a fresh alimentary ball coming up from the paunch to the mouth to be chewed. Ball by ball, the mass of fodder accumulated in the paunch comes back thus to be ground by the teeth to the right degree of fineness and then swallowed for good.”