Mr. Presiding Justice McSurely delivered the opinion of the court.
5. Guaranty, § 7*—when guarantor estopped to deny consideration of guaranty or validity of original undertaking. In an action on a contract of guaranty the guarantor is estopped to deny the consideration of the guaranty or the validity of the original undertaking. 6. Guaranty, § 7*-—when consideration of guaranty may not he determined. In an action on a guaranty founded on a new consideration, independent of the consideration of the original undertaking, the consideration of the original undertaking cannot be inquired into as it forms no part of the consideration of the guaranty, but it is otherwise where the guaranty is made, at the same time as or before the original undertaking, since in such case the consideration of the original undertaking is also the consideration of the guaranty.