But one transaction is involved, and the resulting written contracts, all executed and effective simultaneously, should be construed as one. In that view, the guaranty of the defendants was properly construed as a covenant dependent upon those entered into by the State Bank, the real plaintiff here. The latter, having been guilty of a substantial breach, has no cause of action against defendants for their subsequent breach. The substantial nonperformance by plaintiff was, in my judgment, sufficient alone to excuse further performance by defendants. That appears to me to be enough to sustain the judgment.
Because consideration of the point seems unnecessary to our decision, I prefer not to say anything concerning the oral evidence received as a supposed aid to construction. It is clear that the guaranty was not one of payment. The undertaking was to make good only the deficiency. What deficiency? Obviously that remaining after plaintiff's failure to collect in the usual course of banking practice in the community. Plaintiff did not take over the bills receivable of the Farmers Bank as an independent transaction. Rather it bought them for the purpose of integration with its own banking business. To my mind, the conclusion follows without aid from extraneous matter that plaintiff was under the duty to exercise a degree of diligence commensurate with the circumstances. *Page 110
Of course the contractual language relied upon by appellant, if considered in isolation, might lead to a contrary result. But it is not to be considered alone. It must be put under the light of all of the writings and especially their purposes. The main purpose was to enable plaintiff to continue the banking business in Monticello. A subsidiary purpose was that defendants should be liable for the deficiency already mentioned. Such being the purposes, there is no language in the contract susceptible, in any proper view of the case, of the interpretation that plaintiff was relieved from all obligation to effect collection of the paper it took over from the Farmers Bank.