Every person is presumed to be sane until the contrary appears. Insanity once being judicially established, is presumed to continue until the contrary is shown. In criminal cases, every person is presumed to be innocent of crime until he is proved guilty beyond a reasonable doubt. Every child born in lawful wedlock is presumed to be legitimate. Every person is presumed to have a natural instinct to self-preservation, and there is a presumption against suicide. An endorsee of a negotiable instrument, who takes it before maturity, for a valuable consideration, in the usual course of business, is presumed to be a bona fide holder. A letter properly directed, stamped and deposited in the mail chute is presumed to have been received by the person to whom addressed in the usual course of business. Seven years' absence unheard from presumes death until overcome. A state of facts once shown to exist is presumed to continue until the contrary appears. Every unmarried woman is presumed to be chaste, and every judgment of a court of record based upon proper averment and proof. A marriage once shown to exist is presumed to continue until its dissolution has been established.

Every man is conclusively presumed to know the law, without proof that he does know it, and no proof to the contrary can be shown.