nant or promise depends) in ever so slight a degree, he can never recover against the defendant, either at law or in equity. The reason is obvious, namely, that by the terms of the contract no performance is due to the plaintiff. And the rule at law is the same, though the condition be implied, so long as no part of the contract has been performed. But if the plaintiff have performed his covenant or promise in part before committing any breach of it, the implied condition is then modified, and only requires the plaintiff to perform his covenant or promise so far as is essential to its main scope and object; and the only effect of a breach by the plaintiff in points not essential will be (not to disable the plaintiff from enforcing the defendant’s covenant or promise, but) to enable the defendant to recover damages against the plaintiff for the breach. In equity, on the other hand, a breach by the plaintiff of his own covenant or promise, if it be only in points not essential, will not disable the plaintiff from enforcing the defendant’s covenant or promise, even though no part of the plaintiff’s covenant or promise have been performed, unless performance by the plaintiff be made by the contract an express condition of performance by the defendant. In justification of this difference between law and equity, it may be said that when a plaintiff, who has broken his own covenant or promise, is permitted to enforce at law the covenant or promise in his favor, no allowance can be made to the defendant for the plaintiff’s breach, but the plaintiff will recover as if he had fully performed on his part, and the defendant must indemnify himself by suing the plaintiff in turn. In equity, on the other hand, the compensation in money to which the defendant is entitled for the plaintiff’s breach will be ascertained in the plaintiff’s suit, and will be deducted from the amount to be paid by the defendant, or added to the amount to be paid by the plaintiff (as the case may be); and this, too (on the principle already explained), without the necessity of the defendant’s filing any cross-bill. If this difference in procedure were the only reason why the common law has a different rule from that which prevails in equity, the justification of equity would be complete; but it may be alleged in support of the common-law rule (with what force the writer will not presume to say) that courts are just as much bound by an implied condition as they are by an express condition, unless some event has happened since the making of the contract which introduces a new element into the case.
