Evidence need not be given in support of a negative allegation, except when such negative allegation is an essential of the statement of the right or title on which the cause of action or defense is founded, nor even in such case when the allegation is a denial of the existence of a document, the cus- tody of which belongs to the opposite party. SOURCE: CCP § 1867. NOTE: Former CCP § 1870 permits the admission of many types of evidence. This subject matter is contained throughout Div. 1 and, therefore, is omitted here. See Gaspard & Co. v. GovGuam, 427 F.2d 276 (1980) regarding a declaration of a litigant as an admission.