leviticus 11:3 Whatsoever parteth the hoof, and is clovenfooted, and cheweth the cud, among the beasts, that shall ye eat. - Free Bible Online

      3-7. Whatsoever parteth the hoof, and is cloven-footed, and cheweth the cud--Ruminating animals by the peculiar structure of their stomachs digest their food more fully than others. It is found that in the act of chewing the cud, a large portion of the poisonous properties of noxious plants eaten by them, passes off by the salivary glands. This power of secreting the poisonous effects of vegetables, is said to be particularly remarkable in cows and goats, whose mouths are often sore, and sometimes bleed, in consequence. Their flesh is therefore in a better state for food, as it contains more of the nutritious juices, is more easily digested in the human stomach, and is consequently more easily assimilated. Animals which do not chew the cud, convert their food less perfectly; their flesh is therefore unwholesome, from the gross animal juices with which they abound, and is apt to produce scorbutic and scrofulous disorders. But the animals that may be eaten are those which "part the hoof as well as chew the cud," and this is another means of freeing the flesh of the animal from noxious substances. "In the case of animals with parted hoofs, when feeding in unfavorable situations a prodigious amount of fœtid matter is discharged, and passes off between the toes; while animals with undivided hoofs, feeding on the same ground, become severely affected in the legs, from the poisonous plants among the pasture" [WHITLAW, Code of Health]. All experience attests this, and accordingly the use of ruminating animals (that is, those which both chew the cud and part the hoof) has always obtained in most countries though it was observed most carefully by the people who were favored with the promulgation of God's law.

JFB.