CHYMOSIS, in medicine, the act of making or preparing chyme. The word comes from χυμός, succus, of χίω, fundo, "I melt." Chymosis, according to some, is the second of the concoctions made in the body; being a repeated preparation of the most impure and gross parts of the chyle, which being rejected by the lacteals, is imbibed by the mesenterics, and thence carried to the liver, to be there elaborated, purified, and subtilized as fresh. It is of this, according to Rogers, that the animal spirits are formed.